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Kupanga magesi kwa adipic acid (chintu chitalikila nylon 66) kuzwa kumafuta aa CA (kusanganya kwa cyclohexanone a cyclohexanol) ninzila iikonzya kuzumanana iikonzya kunjila mubusena bwanzila zyakale ziyandika bukkale bukatazya. Nokuba boobo, kucheya kwanguzu zyamagesi antoomwe akuzundana kwakusanduka kwa oxygen zilalesya kubelesegwa mumafakitali. Mumulimo ooyu, twakachincha nickel double hydroxide antoomwe a vanadium kuti tuyungizye bupati bwa current akubamba faradaic efficiency (>80%) muchiindi chilamfu (1.5–1.9 V vs. reversible hydrogen electrode). Ziiyo zyakusola azyakuyeeyela zyakayubununa milimo yobile mipati ya V modification, ikuswanizya akufwambaana kuyaka catalyst akusumpula cyclohexanone adsorption. Mbuli bumboni bwamuzeezo, twakayaka mbungano ya membrane-electrode yakapanga adipic acid a faradaic efficiency mpati (82%) akupanga (1536 μmol cm-2 h-1) a current density (300 mA cm-2), mpawo katujana kukkalikana >50 h. Mulimu ooyu utondeezya chintu chibotu chakugwasya kupanga magesi aa adipic acid mpawo chikonzya kuchita obotu mumakwebo.
Adipic acid (AA) nimwi ya aliphatic dicarboxylic acids iiyandikana loko alimwi ibelesyegwa kapati mukupanga nylon 66 azimwi polyamides naakuti polymers1. Mumakwebo, AA ilapangwa kwiinda mukusanzya musamu wa cyclohexanol a cyclohexanone (nkokuti, mafuta aa AA) kubelesya 50-60 vol% ya nitric acid mbuli chintu chipa kuti kube muya. Eeyi nzila ilaa ntenda zyabusena zijatikizya kuzwa kwa nitric acid a nitrogen oxides (N2O a NOx) mbuli muya uusofweede2,3. Nikuba kuti H2O2 ilakonzya kubelesegwa mbuli nzila imwi yakugwisya muya mubotu, muulo wayo mupati abukkale bukatazya bwakupanga zipa kuti kakutazya kubelesegwa, mpawo nzila iitaduli alimwi iitamani ilayandika4,5,6.
Muminyaka iilikumi yainda, nzila zyakupanga makemikalu amafuta zyakakwela maanu kapati kuzwa kulibasayaansi akaambo kabubotu bwazyo bwakubelesya manguzu aakonzya kubelesegwa lubo akubeleka muchiimo chitete (nkokuti, kupya kwamukati akutontola kwamukati)7,8,9,10. Muleezi, kuyaambele kwakusandula mafuta aa KA kuya ku AA nchintu chipati loko kuti tujane bubotu buli atala aawa antoomwe akugwisya kubelesya nitric acid a nitrous oxide emissions zijanika mukupanga zintu zyachiindi (Chitondeezyo 1a). Mulimo wakusaanguna wakachitilwa a Petrosyan abamwi, aabo bakaamba kuti nzila ya electrocatalytic oxidation ya cyclohexanone (COR; cyclohexanone naa cyclohexanol yakavwuntauzyigwa kuti yiiminina mafuta aa KA) aa nickel oxyhydroxide (NiOOH), pesi bunji bwa current density (6 cm-A-25%) antoomwe a A (A25%) yakazwa aakati-akati wakajanwa11,12. Kuzwa aawo, kuyaambele kupati kwakachitwa mukupanga zintu zibelesya nickel kuti ziyungizye mulimo wa COR. Mbuli chitondeezyo, copper-doped nickel hydroxide (Cu-Ni(OH)2) catalyst yakapangwa kuti isumpule Cα–Cβ cleavage mu cyclohexanol13. Ino-ino twakaamba Ni(OH)2 catalyst yakacincwa a sodium dodecyl sulfonate (SDS) kuti ipange busena butakwe maanzi buvwubya cyclohexanone14.
a Mapenzi aakupanga AA kwiinda mukubelesya magesi aa KA oil. b Kweezyanisya kwa COR ya electrocatalytic ya Ni-based catalysts yakaambwa musule antoomwe a catalyst yesu munzila yama electrode otatwe anzila ya flow battery11,13,14,16,26. Makani aasalala aatala azyeelelo zyakusanduka akuchita kwasanduka alapegwa muMatebulu Aayungizyidwe 1 a 2. c Kubeleka kwa NiV-LDH-NS catalysts yesu ya COR mu H-cell reactor a MEA, eezyo zibeleka aanguzu zyiingi.
Nikuba kuti nzila zyaambwa atala aawa zyakasumpula mulimo wa COR, zibelesyo zya Ni-based zyaambwa zyakatondezya kubeleka kabotu kwa AA Faraday (FE) (>80%) buyo aawo mpozili aansi, kanjikanji munsi aa 1.6 V kweelanisigwa a reversible hydrogen electrode (RHE, mubufwaafwi VRHE). Aboobo, bunji bwamagesi bwakaambwa (nkokuti, bunji bwamagesi boonse bwavwuzyigwa a FE) bwa AA lyoonse buli munsi aa 60 mA cm−2 (Mufanikisyo 1b a Supplementary Table 1). Bunji bwamagesi busyoonto buli munsi kapati aazyeezyo ziyandika mumafakitali (>200 mA cm−2)15, eezyo zipa kuti kutabi nzila zyakubelesya magesi zyakupanga AA (Chitondeezyo 1a; atala). Kuyungizya nguzu zyamagesi, nguzu zibotu (kunzila yama electrode otatwe) naakuti nguzu zyamagesi zisumpukide (kunzila yama electrode obile) zilakonzya kubelesegwa, eezi ninzila nguba yakusanduka kwamagesi, ikapati kusanduka kwa oxygen (OER). Nokuba boobo, kuli COR aa anodic potentials mpati, OER ilakonzya kuba sikuzundana mupati mukucheesya FE ya AA, aboobo kuchesya kubelesya manguzu (Chitondeezyo 1a; munsi). Mbuli chitondeezyo, mukulanga-langa kuyaambele kwakainda (Mufanikisyo 1b a Supplementary Table 1), twakatyompwa kujana kuti FE ya AA a SDS-modified Ni(OH)2 yakaselemuka kuzwa ku 93% kusika ku 76% akuyungizya nguzu zyakabelesegwa kuzwa ku 1.5 VRHE kusika ku 1.7 VRHE14, mpawo FE ya AA a Cu(OH)-Ni(OH)2 wakaseluka kuzwa ku 1.5 VRHE 93% kusika ku 69% akuyungizya nguzu kuzwa ku 1.52 VRHE kusika ku 1.62 VRHE16. Aboobo, mweelwe wa AA uutegwa partial current density tauyungizyi pe kweendelana aawo mpaali aanguzu zisumpukide, eezyo zipa kuti AA itabeleki kabotu, kakutali kwaambuula akubelesya manguzu manji akaambo ka FE nsyoonto ya AA. Mukuyungizya kuzibelesyo zibelesya nickel, zibelesyo zibelesya cobalt azyalo zyakatondezya nguzu zyakugwasya mu COR17,18,19. Nokuba boobo, kubeleka kabotu kwazyo kulaselemuka aanguzu zipati, mpawo kweelanisigwa a Ni-based catalysts, zilakonzya kulesya kubelesya mumafakitali, mbuli kuchincha kwamiulo kupati antoomwe azintu ziche. Aboobo, nchibotu kupanga Ni-based catalysts zili a current density mpati a FE mu COR kuchitila kuti chikonzyeke kujana AA mpati.
Mumulimo ooyu, twaambilizya vanadium(V)-modified nickel layered double hydroxide nanosheets (NiV-LDH-NS) mbuli magesi aagwasya kapati mukupanga AA kwiinda mu COR, aayo abeleka aanguzu zyiingi a OER yakasinkilidwe, ikuzuzikizya FE mpati a current density muli H-cells antoomwe ama membrane electrode (Chitondeezyo 1AME b). Tusaanguna kutondezya kuti acetylene oxidation efficiency kwiinda Ni(OH)2 nanosheet catalyst (Ni(OH)2-NS) ilaselemuka, mbuli mbokulangilwa, aawo mpaali manguzu manji, kuzwa ku 80% a 1.5 VRHE kusika ku 42% a 1.9 VRHE. Mukwiimpana kupati, nikwakamana kuchincha Ni(OH)2 a V, NiV-LDH-NS yakatondeezya nguzu zyamagesi zisumpukide aawo mpakonzya kuchita obotu, mpawo chakagwasya loko, yakabamba FE mpati muchiindi chilamfu. Mbuli chitondeezyo, a 1.9 VRHE, yakatondezya bupati bwa 170 mA cm−2 antoomwe a FE ya 83%, eeyo njiikonzya kugwasya COR munzila yama electrode otatwe (Fig. 1c a Supplementary Table 1). Data yakusola ayakuyeeyela itondezya kuti kucinca kwa V kusumpula kucesya kuzwa ku Ni(OH)2 kuya ku Ni oxyhydroxides (Ni3+xOOH1-x) iijisi nguzu kapati, eezyo zibeleka mbuli cibeela cibeleka ca COR. Kwiindawo, kuchincha kwa V kwakasumpula kunjila kwa cyclohexanone atala aa catalyst, ooko kwakagwasya kapati mukulesya OER aa anodic potentials mpati. Kutondezya nguzu zya NiV-LDH-NS muchiimo cheenzu, twakabamba MEA flow reactor mpawo twakatondezya FE ya AA (82%) a industrially current density (300 mA cm−2), eeyo iili atala kapati kwiinda mpindu zyesu zyakainda mu membrane flow reactor (Fig. 1b a Supplementary Table 2). Mweelwe wa AA (1536 μmol cm−2 h−1) wakali mupati kwiinda wakajanwa kwiinda mukubelesya nzila ya thermal catalytic (<30 mmol gcatalyst−1 h−1)4. Kuya kunembo, chitondeezyo chakatondezya kukkalikana kubotu aawo notubelesya MEA, akubamba FE >80% AA kwamahola aali 60 a 200 mA cm−2 antoomwe a FE >70% AA kwamahola aali 58 a 300 mA cm−2. Kumamanino, chiiyo chakusaanguna (FEA) chakatondezya kugwasya kwanzila ya electrocatalytic mukupanga AA.
Kweelana amabbuku aakalembwa musule, Ni(OH)2 nchintu chikonzya kugwasya COR, aboobo Ni(OH)2-NS13,14 yakapangwa mchiindi chakusanguna kwiinda mukubelesya nzila ya coprecipitation. Izyakutondezya zyakatondezya bupange bwa β-Ni(OH)2, eezyo zyakasinizyigwa a X-ray diffraction (XRD; Fig. 2a), mpawo ultra-thin nanosheets (bupati: 2–3 nm, bupati bwakumbali: 20–50 nm) zyakabonwa a high-resolution transmission electron microscopy (HRTEM Supplement Fig. 1) alimwi a microscopy ya microscopy . (AFM) zipimyo (Chitondeezyo Chakuyungizya 2). Kuswaangana kwama nanosheets akwalo kwakabonwa akaambo kabube bwawo buteteete loko.
a X-ray diffraction patterns ya Ni(OH)2-NS antoomwe a NiV-LDH-NS. FE, kwiinda, antoomwe a AA current density a b Ni(OH)2-NS antoomwe a c NiV-LDH-NS aanguzu zisiyene. Mibala yakulubizya yiiminina kusiyana kwazyeelelo zyotatwe zitabelesyegwi kubelesya chintu chomwe. d HRTEM mufanikisyo wa NV-LDH-NS. Chipimyo: 20 nm. HAADF-STEM mufanikisyo wa NiV-LDH-NS antoomwe amaapu yazibeela zitondezya kwaabwa kwa Ni (mubala wa sokwe), V (mubala wa mubala wa mubala wa mubala wa mubala wa mubala wa mubala wa mubala wa bbululu). Chipimyo: 100 nm. f Ni 2p3/2, g O 1 s, antoomwe a h V 2p3/2 XPS data ya Ni(OH)2-NS (atala) a NiV-LDH-NS (ansi). i FE a j nzintu zibeleka AA aama catalysts obile muziindi zili 7. Zibeela zyakulubizya ziiminina kusiyana kwazyeelelo zyotatwe zitabelesyegwi kubelesya chintu chomwe mpawo zili mukati ka 10%. Data iitakwe mulimo ya a-c a f-j ilapegwa muma fayila aa data iitakwe mulimo.
Mpawo twakalanga-langa mulimo wa Ni(OH)2-NS a COR. Kubelesya nzila yakubelesya magesi iitacinci, twakajana 80% FE ya AA aanguzu zisyoonto (1.5 VRHE) kakunyina OER (Chitondeezyo 2b), kutondezya kuti COR ilaanguzu kwiinda OER aanguzu zisyoonto zya anodic. Chintu chipati chakajanwa kuti ni glutaric acid (GA) a FE ya 3%. Kubako kwamweelwe wa succinic acid (SA), malonic acid (MA), antoomwe a oxalic acid (OA) akwalo kwakapimwa a HPLC (Langa Supplementary Figure 3 kuti ujane kwaabwa kwazintu). Kunyina asidi yafoomu yakajanwa muchintu eechi, kutondeezya kuti carbonate ilakonzya kupangwa mbuli chintu cha C1. Kusunka muzeezo ooyu, magesi kuzwa kukusanduka kwa 0.4 M cyclohexanone akabikkwa asidi mpawo zintu zyakazwa mumuwo zyakabikkwa mumusamu wa Ca(OH)2. Mukujana mpindu, musamu wakaba mutete, wakasinizya kupangwa kwa carbonate nikwakamana kugwisigwa magesi. Nokuba boobo, akaambo kakuti magesi azwa muchiindi cha electrolysis (Chitondeezyo 2b, c), bunji bwa carbonate buli munsi alimwi bulakatazya kuzyiba. Mukuyungizya, zimwi zintu zya C2-C5 zilakonzya kupangwa, pesi mweelwe wazyo taukonzyi kubalwa pe. Nikuba kuti mweelwe woonse wazintu zyakabambwa ulakatazya kuzyiba, 90% yazyoonse zyeelene aama electrochemical zitondezya kuti bunji bwanzila zya electrochemical zyazyibwa, eezyo zipa ntalisyo yakumvwisisisya kwesu. Akaambo kakucheya kwanguzu zyamagesi (20 mA cm−2), mweelwe wa AA wakali 97 μmol cm−2 h−1 (Mufanikisyo 2b), weelene a 19 mmol h−1 g−1 kweendelanya abulemu bwakubikkwa kwa catalyst (5 mg cm−2), oobo buli munsi a thermal catalytic productivity (~30 mm−1 h−1 g−1) h−1. Eelyo nguzu zyakabelesegwa nizyakatanta kuzwa ku 1.5 kusika ku 1.9 VRHE, nikuba kuti bunji bwamagesi bwakatanta (kuzwa ku 20 kusika ku 114 mA cm−2), kwakaba kuseluka kupati kwa AA FE, kuzwa ku 80% kusika ku 42%. Ikuceya kwa FE aawo mpokugolela zintu zibotu kulachitika akaambo kakuzundana kwa OER. Ikapati a 1.7 VRHE, muzundano wa OER usololela kukucheya kupati kwa AA FE, aboobo kuchesya mbichani kubeleka kwa AA antoomwe akuyungizya bunji bwa current. Aboobo, nikuba kuti bunji bwa AA bwakatanta kuzwa ku 16 kusika ku 48 mA cm−2 mpawo AA yakatanta (kuzwa ku 97 kusika ku 298 μmol cm−2 h−1), nguzu zyiingi zyakabelesegwa (2.5 W h gAA−1 kuzwa ku 1.5 kusika ku 1.9 VRHE), zyakapa kuti kube kuyungizigwa kwakuzwa kwa CO 27 g. gAA−1 (makani aakubala alilembedwe mu Supplementary Note 1). OER yakaambwa musule mbuli sikuzundana a COR reaction aa anodic potentials mpati ileendelana amalipooti aakaindi alimwi itondezya buyumuyumu bwakusumpula AA productivity14,17.
Kuti tupange Ni(OH)2-NS-based COR catalyst iibeleka obotu, twakasaanguna kulanga-langa chiindi chibeleka. Twakabona nsumbu zya 473 cm-1 antoomwe a 553 cm-1 muzintu zyesu zya in situ Raman spectroscopy (Supplementary Fig. 4), kweendelana akugonka akutandabika kwa Ni3+-O bonds mu NiOOH, kweendelana. Kwakalembedwe kuti NiOOH nchintu chiboola akaambo kakucheya kwa Ni(OH)2 akuyoboloka kwa Ni(OH)O kuma anodic potentials, mpawo nchintu chibeleka mu electrocatalytic oxidation20,21. Aboobo, tulangila kuti kufwambaanya nzila yakuyakulula Ni(OH)2 kuya ku NiOOH kulakonzya kuyungizya mulimo wa COR.
Twakasola kuchincha Ni(OH)2 azintu zisiyene-siyene nkaambo kwakabonwa kuti kuchincha kwa heteroatom kusumpula kuyakulula kwachiimo muzibulo zyakucinca zya oxides/hydroxides22,23,24. Izyakutondezya zyakabambwa kwiinda mukubikka antoomwe Ni antoomwe abutale bwabili. Akati kamasampu aasiyene-siyene aakasandulwa abutale, musamu wakasandulwa a V (V:Ni atomic ratio 1:8) (wiitwa kuti NiV-LDH-NS) wakatondezya bunji bwamagesi mu COR (Supplementary Fig. 5) alimwi chiyandikana loko, AA FE mpati kwiinda muchiindi chilamfu. Mubwini, aanguzu ziche (1.5 VRHE), bunji bwa NiV-LDH-NS bwakali 1.9 ziindi kwiinda bwa Ni(OH)2-NS (39 vs. 20 mA cm−2), mpawo AA FE yakalikozyenye kulizyoonse zyobile (83% vs. 80%). Akaambo kakuvwula kwanguzu zyamagesi antoomwe a FE AA iikozyenye, buvwubi bwa NiV-LDH-NS bulisumpukide ziindi zili 2.1 kwiinda bwa Ni(OH)2-NS (204 vs. 97 μmol cm−2 h−1), kutondezya kusumpula kucinca kwa V kubunji bwamagesi aanguzu zisyoonto (Chitondeezyo 2c).
Aakuyungizya nguzu zibelesegwa (nkokuti, 1.9 VRHE), bunji bwamazubaano aa NiV-LDH-NS buli 1.5 ziindi kwiinda bwa Ni(OH)2-NS (170 vs. 114 mA cm−2), mpawo kuyungizigwa ooku kulikozyenye akwaa nguzu zili munsi (1.9 ziindi zyiingi). Chazibinkene, NiV-LDH-NS yakabamba AA FE mpati (83%) mpawo OER yakasinkililwa kapati (O2 FE 4%; Cifwanikiso 2c), kwiinda Ni(OH)2-NS alimwi azyakali kwaambwa musyule zyakali a AA FE nsyoonto kapati aa anodic potentials mpati (Supplementary Table 1). Akaambo ka FE mpati ya AA muwindo lyanguzu (1.5–1.9 VRHE), mweelwe wa AA wakupanga wa 867 μmol cm−2 h−1 (weelene a 174.3 mmol g−1 h−1) wakajanwa a 1.9 VRHE, kutondezya kubeleka kabotu mu electrocatalytic alimwi a thermotatic systems eelyo bupati bwazintu nobwakabikkwa munzila iili kabotu kubikka zintu zya NiV-LDH-NS (Supplementary Figure. 6).
Kuti tumvwisisisye bupati bwanguzu zyamagesi antoomwe a FE mpati muchiindi chilamfu nikwakamana kuchincha Ni(OH)2 a V, twakapandulula bupange bwa NiV-LDH-NS. Izyazwa mu XRD zyakatondezya kuti kucinca a V kwakapa kuti kube kusanduka kuzwa ku β-Ni(OH)2 kuya ku α-Ni(OH)2, mpo taakwe V-related crystalline species yakajanwa (Fig. 2a). Izyazwa mu HRTEM zitondezya kuti NiV-LDH-NS ilakona bupange bwa Ni(OH)2-NS nanosheets ziteteete loko mpawo ilijisi bupati bukozyenye (Fig. 2d). Kupima kwa AFM kwakatondeezya kuti ma nanosheets alakonzya kuswaangana, mpawo kwakapa kuti kube bupati bwa 7 nm (Supplementary Fig. 7), oobo bupati kwiinda bwa Ni(OH)2-NS (bupati: 2-3 nm). Kuvwuntauzya kwa X-ray spectroscopy (EDS) kwakatondeezya kuti V a Ni zyakali kwaabwa kabotu muma nanosheets. Kupandulula bupange bwamagesi bwa V amulimu wayo a Ni, twakabelesya X-ray photoelectron spectroscopy (XPS) (Chitondeezyo 2f-h). Ni(OH)2-NS yakatondezya bube bwakuzungaana kwa Ni2+ (mutwe wamwanakazi a 855.6 eV, mutwe wa satellite a 861.1 eV, Cifwanikiso 2f)25. I O 1 s XPS spectrum ya Ni(OH)2-NS ilakonzya kwaandaanizyigwa muzibeela zyotatwe, akati kazyeezyo zibeela zili a 529.9, 530.9 a 532.8 eV zyeendelezyegwa a lattice oxygen (OL), hydroxyl group (Ni-OH) antoomwe a oxygen iijatikizyidwe atala (OA), kweendelana (Figures 2g)26,27,28,29. Musule akusandulwa a V, V 2p3/2 peak yakaboneka, eeyo iikonzya kubola muzibeela zyotatwe zili a 517.1 eV (V5+), 516.6 eV (V4+) antoomwe a 515.8 eV (V3+), kweendelana, kutondezya kuti musyobo wa V mubupange ujanika kapati muchiimo cha oxidation (Chitondeezyo, 2035, 2035). Mukuyungizya, Ni 2p peak a 855.4 eV mu NiV-LDH-NS yakasanduka munzila iitali kabotu (a 0.2 eV) kweelanisigwa a Ni(OH)2-NS, kutondezya kuti ma electron akagwisigwa kuzwa ku V kuya ku Ni. Chiimo cha Ni chakabonwa musule akusandulwa kwa V chakali kweendelana a Ni K-edge X-ray absorption near-edge spectroscopy (XANES) zyakazwa (Langa "V Modification Promotes Catalyst Reduction" munsi kuti ujane makani manji). NiV-LDH-NS nikwakamana kusilikwa a COR kwawoola lyomwe yakasalwa kuti NiV-LDH-POST mpawo yakajanwa kwiinda mukubelesya transmission electron microscopy, EDS mapping, X-ray diffraction, Raman spectroscopy, antoomwe a XPS measurements (Supplementary Figs. 8 a 9). Zibelesyo zyakasyaala mbuli zintu zyakabungene antoomwe a nanosheet morphology (Supplementary Fig. 8a–c). Bubotu bwama sampuli bwakaceya mpawo bunji bwa V bwakaseluka akaambo kakuvwundauka kwa V akuyakululwa kwa catalyst (Supplementary Fig. 8d–f). I XPS spectra yakatondezya kucheya kwa V peak intensity (Supplementary Fig. 9), eeyo yakajanwa akaambo kakuzwa kwa V. Mukuyungizya, O 1s spectrum analysis (Supplementary Fig. 9d) antoomwe a electron paramagnetic resonance (EPR) measurements (Supplementary Fig. 10) zyakatondezya kuti mweelwe wa oxygen vacancies a NiV-LDH-NS wakatanta musule lya 1 h ya electrolysis, zikonzya kuleta kucinca kutali kabotu mu NiV-LDH-NS spectrum energy ( Supplementary Figs. 9d a Supplementary Figs. 9d. 10 kuti ujane makani manji)26,27,32,33. Aboobo, NiV-LDH-NS yakatondezya kucinca kusyoonto kwachiimo nikwakainda 1 h ya COR.
Kusinizya mulimo mupati wa V mukusumpula COR, twakapanga NiV-LDH catalysts a V:Ni atomic ratios yiindene (1:32, 1:16, a 1:4, zyaambwa kuti NiV-32, NiV-16, antoomwe a NiV-4, kweendelana) kunze lya 1:8 anzila njiyonya ya coprecipitation. Izyazwa mu EDS zitondezya kuti V:Ni atomic ratio mu catalyst ili afwaafwi a precursor (Supplementary Fig. 11a–e). Aawo kuyaambele kwakucinca kwa V, nguzu zya V 2p spectrum zilatanta, mpawo nguzu zyakujata zya Ni 2p zilazumanana kuchincha kuya kulubazu lutali kabotu (Supplementary Fig. 12). Aawo awo, mweelwe wa OL wakatanta asyoonto-asyoonto. Zyakazwa mukusola kwa catalytic zitondezya kuti OER ilakonzya kulesyegwa nikuba kuti V yakacincwa (V:Ni atomic ratio ya 1:32), a O2 FE niyaselemuka kuzwa ku 27% kusika ku 11% a 1.8 VRHE nikwakachinchwa V (Supplementary Fig. 11f). Aawo mweelwe wa V:Ni wakatanta kuzwa ku 1:32 kusika ku 1:8, mulimo wakugwasya wakatanta. Nokuba boobo, akuyungizigwa kwakusanduka kwa V (V:Ni ratio ya 1:4), bunji bwamazubaano bulaselemuka, ooko nkotuyeeyela kuti nkucheya kwabunji bwa Ni active sites (ikapati NiOOH active phase; Supplementary Fig. 11f). Akaambo kakusumpula mulimo wakusanduka kwa V akukwabilila masena aa Ni, chintu chipa kuti kube V:Ni ratio ya 1:8 chakatondezya FE a AA mpati loko mu V:Ni ratio screening test. Kuti tusalazye naa mweelwe wa V:Ni ulazumanana kuba mbubonya musule lyakusanduka kwa magesi, bupange bwazintu zyakabelesegwa bwakaambwa. Zyakazwa muzyaambilizyo zitondezya kuti kuli zibelesyo zyakusaanguna zya V:Ni kuzwa ku 1:16 kusika ku 1:4, V:Ni ratio yakaselemuka kusika ku 1:22 musule lyakusanduka, eezi zilakonzya kuba akaambo kakuzwa kwa V akaambo kakuyakululwa kwa catalyst (Supplementary Fig. 13). Kozyiba kuti AA FEs zyeelene zyakabonwa aawo V:Ni ratio yakusaanguna niyakali kweelana naa kwiinda 1:16 (Supplementary Fig. 11f), eecho chikonzya kupandululwa akuyakululwa kwa catalyst kwakapa kuti kube V:Ni ratios zikozyenye mu catalysts kutondezya kweezyanisya kwa catalytic.
Kuyungizya kusinizya mbociyandika V-modified Ni(OH)2 mukusumpula mulimo wa COR, twakabamba nzila zimbi zyobile zyakupanga zintu zyakunjizya V muzintu zya Ni(OH)2-NS. Imwi ninzila yakusanganya, mpawo musamu wiitwa kuti NiV-MIX; aimbi ninzila yakutobelana, mpawo musamu wiitwa kuti NiV-SP. Twaambo twakusanganya tulapegwa muchibeela chaNzila. Maapu ya SEM-EDS yakatondeezya kuti V yakazwidilila kuchinchululwa a Ni(OH)2-NS atalaa zitondezyo zyoonse zyobile (Supplementary Fig. 14). Izyazwa mu electrolysis zitondezya kuti a 1.8 VRHE, AA efficiency a NiV-MIX antoomwe a NiV-SP electrodes zili 78% antoomwe a 79%, zyoonse zyobile zitondezya bubotu bupati kwiinda Ni(OH)2-NS (51%). Kwiindawo, OER a NiV-MIX antoomwe a NiV-SP ma electrode yakasinkililwa (FE O2: 7% a 2%, kweendelana) kweelanisigwa a Ni(OH)2-NS (FE O2: 27%). Eezyi mpindu zisinizya bubotu bwakucinca kwa V mu Ni(OH)2 mukulesya OER (Supplementary Fig. 14). Nokuba boobo, kukkalikana kwazibelesyo kwakanyonganizyigwa, ooko kwakatondezyegwa akuseluka kwa FE AA a NiV-MIX kusika ku 45% alimwi a NiV-SP kusika ku 35% nokwakainda ziindi zili ciloba zya COR, calo caamba kuti kuyandika kubelesya nzila zyeelede zyakukkazika misyobo ya V, mbuli kucinca kwa V mu Ni(OH)2 latti mu Nice-VNS-VNS, eeco ncecintu ciyandika kapati mumulimo ooyu.
Twakalanga lubo kukkalikana kwa Ni(OH)2-NS antoomwe a NiV-LDH-NS kwiinda mukubikka COR muziindi zyiingi. Ikusanduka kwakachitwa kwawoola lyomwe muchiindi chomwe mpawo electrolyte yakachinchwa musule lyamweelwe umwi awumwi. Musule lya 7th cycle, FE a AA zyakali kubeleka a Ni(OH)2-NS zyakaselemuka a 50% a 60%, kweendelana, mpawo kuyungizigwa kwa OER kwakabonwa (Fig. 2i, j). Nikwakainda kuzyunguluka kuli koonse, twakali kulanga-langa nzila zya voltammetry (CV) zyama catalysts mpawo twakabona kuti oxidation peak ya Ni2+ yakaselemuka asyoonto-asyoonto, kutondezya kucheya kwa redox ability ya Ni (Supplementary Fig. 15a–c). Antoomwe akuyungizya kwa Ni cation mu electrolyte muchiindi cha electrolysis (Supplementary Fig. 15d), tulaamba kuti kumana kwakubeleka (kucheya kwa FE antoomwe a AA) nkuzwa kwa Ni kuzwa ku catalyst, eezi zyakapa kuti Ni foamed substrate itondezye OER activity. Mukwiimpana, NiV-LDH-NS yakacesya kuseluka kwa FE antoomwe a AA kusika ku 10% (Mufanikisyo 2i, j), kutondezya kuti kucinca kwa V kwakasinkila Ni kuzwa (Mufanikisyo Wakuyungizya 15d). Kuti tumvwisisisye kusima kwa V modification, twakachita myeelwe ya theoretical. Kweelana amabbuku aakalembwa musule34,35, kucinca kwa enthalpy munzila yakugwisya nsimbi zyama atomu aabutale atalaa nyika iibeleka ya catalyst kulakonzya kubelesyegwa mbuli bupanduluzi buli kabotu bwakupima kukkalikana kwa catalyst. Aboobo, kucinca kwa enthalpy kwa nzila yakugwisya ma atomu aa Ni atalaa (100) atala aa Ni(OH)2-NS alimwi a NiV-LDH-NS (NiOOH a NiVOOH, kweendelana) kwakayeeyelwa (makani aajatikizya kuyakwa kwacitondezyo alapandululwa mu Supplementary Note 2 alimwi a Supplementary Fig. 16). Nzila yakugwisya Ni kuzwa ku NiOOH a NiVOOH yakatondezyegwa (Supplementary Figure. 17). Muulo wanguzu zyakugwisya Ni a NiVOOH (0.0325 eV) ulisumpukide kwiinda wa NiOOH (0.0005 eV), kutondezya kuti kucinca kwa V kulasumpula kukkalikana kwa NiOOH.
Kusinizya mulimo wakulesya OER ku NiV-LDH-NS, ikapati aawo anodic potentials mpati, differential electrochemical mass spectrometry (DEMS) yakachitwa kuti ivwuntauzye kupangwa kwa O2 kweendelanya anguzu zya O2 mumasampulo aasiyene. Izyazwa zyakatondezya kuti kakunyina cyclohexanone, O2 a NiV-LDH-NS yakaboneka a 1.53 VRHE, eeyo yakali munsi asyoonto kwiinda ya O2 a Ni(OH)2-NS (1.62 VRHE) (Supplementary Fig. 18). Eechi chakazwa chitondeezya kuti kukasya OER kwa NiV-LDH-NS muchiindi cha COR inga tiikwaba akaambo kakubeleka kwa OER kusyoonto, ooko kweendelana abulemu bupati buli mu linear sweep voltammetry (LSV) curves a NiV-LDH-NS kwiinda Ni(OH)2-NS kakunyina cyclohan (Chitondeezyo 19). Musule akubikkwa kwa cyclohexanone, kuchedwa kwakusanduka kwa O2 (ambweni akaambo kabubotu bwa thermodynamic bwa COR) kupandulula FE mpati ya AA mubusena butakwe nguzu. Ichakatazyide loko, OER yakutalisya nguzu zya NiV-LDH-NS (1.73 VRHE) ilachedwa kwiinda Ni(OH)2-NS (1.65 VRHE), eezi zyeendelana a FE mpati ya AA antoomwe a FE nsyoonto ya O2 a NiV-LDH-NS aanguzu zibotu (Chitondeezyo 2c).
Kuti tuyungizye kumvwisisisya kusumpula kucinca kwa V, twakavwuntauzya OER antoomwe a COR zyakuchita a Ni(OH)2-NS antoomwe a NiV-LDH-NS kwiinda mukupima Tafel slopes zyabo. Nchintu chibotu kuzyiba kuti bunji bwazintu ziliwo lino muchisi cha Tafel buli akaambo kakusanduka kwa Ni2+ kuya ku Ni3+ muchiindi chakusunkwa kwa LSV kuzwa ku nguzu ziche kuya ku nguzu zipati. Kuchesya ntenda ya Ni2+ oxidation a COR Tafel slope measurement, twakasaanguna ku oxidation catalyst a 1.8 VRHE kwamaminiti aali kkumi mpawo twakachita LSV tests munzila ya reverse scan mode, nkokuti, kuzwa ku nguzu zipati kuya ku nguzu ziniini (Supplementary Fig. 20). LSV curve yakusaanguna yakalulamikwa a 100% iR compensation kuti kujane Tafel slope. Kakwiina cyclohexanone, Tafel slope ya NiV-LDH-NS (41.6 mV dec−1) yakali munsi kwiinda ya Ni(OH)2-NS (65.5 mV dec−1), kutondezya kuti OER kinetics ilakonzya kusumpulwa a V modification (Supplementary Fig. 20c). Musule akubikkwa kwa cyclohexanone, Tafel slope ya NiV-LDH-NS (37.3 mV dec−1) yakali munsi kwiinda ya Ni(OH)2-NS (127.4 mV dec−1), kutondezya kuti kucinca kwa V kwakajisi nguzu zyakunyanyaasya mubili ku COR kweelanisigwa a OER (Supplementary Fig. 20). Eezyi mpindu zitondezya kuti nikuba kuti kucinca kwa V kusumpula OER kusikila ambali, kufwambaanya kapati kweenda kwa COR, akupa kuti FE ya AA iyungizigwe.
Kuti tumvwisisisye kusumpulwa kwakucinca kwa V aatala akubeleka kwa FE a AA, twakabikkila maanu kukwiiya nzila. Malipooti amwi aakainda atondezya kuti kucinca kwa heteroatomu kulakonzya kucesya bube bwama catalysts akuyungizya busena bwa electrochemically active surface (EAS), aboobo akuyungizya mweelwe wamasena aabeleka aboobo akusumpula mulimo wa catalytic36,37. Kuvwuntauzya kuti eezi zilakonzya kuchitika, twakachita zyeelelo zya ECSA kakutanaba akumana kwakubelesya magesi, mpawo mpindu zyakatondezya kuti ECSA ya Ni(OH)2-NS antoomwe a NiV-LDH-NS zyakali kwelanisigwa (Supplementary Fig. 21), kakutabikkilizyi nsungwaazyo ya active site density nikwakamana V modification ku catalytic enhancement.
Kweelana aluzibo luzuminwa abantu boonse, mu Ni(OH)2-catalyzed electrooxidation of alcohols naa zimwi zintu zijisi nguzu zya nucleophilic, Ni(OH)2 isaanguna kusweekelwa ma electrons ama protons mpawo yacheya kuba NiOOH kwiinda munzila zya electrochemical a anodic potential imwi38,39,40,41. NiOOH yakabambwa mpawo ibelekela mbuli COR iibeleka loko kuti igwisye haayidirojeni ama electron kuzwa kuchintu chiyumu kwiinda mukubelesya nzila zyamakemikalu kuti ipange chintu chili a oxidized20,41. Nokuba boobo, kwakaambwa lino-lino kuti nikuba kuti kucheya kusika ku NiOOH inga kwabeleka mbuli ntaamu yakusala mweelwe (RDS) wa electrooxidation ya bukoko a Ni(OH)2, mbuli mbokwaambidwe mumabbuku aakalembwa ino-ino, oxidation ya Ni3+ alcohols ilakonzya kuba chintu chichitika biyo kwiinda mu non-redox electron transfer kwiinda mu orbitals zitakwe bantu zya Ni(OH)244. Kakusololelwa akuvwuntauzya kwakacitwa mumabbuku ngaonya, twakabelesya dimethylglyoxime disodium salt octahydrate (C4H6N2Na2O2 8H2O) mbuli molecule yakuvwuntauzya kuti tujate kufumbwa Ni2+ kuzwa kukucheya kwa Ni3+ muchiindi cha COR (Supplementary Fig. 22 and Supplementary Note 3). Izyazwa zyakatondezya kupangwa kwa Ni2+, kusinizya kuti kucesya kwamakemikalu kwa NiOOH akusanduka kwa Ni(OH)2 kwakachitika achiindi chomwe muchiindi cha COR. Aboobo, mulimo wa catalytic ulakonzya kuyeeme kapati a kinetics ya Ni(OH)2 kucesya kuba NiOOH. Kwiinda muchiimo eechi, twakavwuntauzya kuti naa kuchincha kwa V inga kwafwambaanya kucheya kwa Ni(OH)2 mpawo akusumpula COR.
Twakasaanguna kubelesya nzila zya Raman kutondezya kuti NiOOH ncecibeela cibeleka ca COR a Ni(OH)2-NS alimwi a NiV-LDH-NS kwiinda mukulanga-langa kupangwa kwa NiOOH muzibeela zibotu alimwi akubelesya kwayo kwakatobela nikwakabikkwa cyclohexanone, kutobela nzila ya “electrochemical” (Figure 3). Kwiindawo, kuchita kwa NiV-LDH-NS yakayakululwa kwakayinda kwa Ni(OH)2-NS, mbuli mbokutondezegwa akufwambaana kuzimaana kwa Ni3+–O Raman signal. Mpawo twakatondezya kuti NiV-LDH-NS yakatondezya nguzu zisyoonto zyakupanga NiOOH kweelanisigwa a Ni(OH)2-NS kakuli naa kakunyina cyclohexanone (Chitondeezyo 3b, c aChitondeezyo Chakuyungizya 4c, d). Chazibinkene, kubeleka kabotu kwa OER kwa NiV-LDH-NS kwapa kuti kube mabbubbu miingi akanamatika kunembo lya Raman measurement objective, eecho chipa kuti Raman peak a 1.55 VRHE imane (Supplementary Fig. 4d). Kweelana azyazwa mu DEMS (Supplementary Fig. 18), bunji bwazintu ziliwo muchiindi chifwiifwi (VRHE < 1.58 kuli Ni(OH)2-NS antoomwe a VRHE < 1.53 kuli NiV-LDH-NS) zilachitika akaambo kakuyakululwa kwa Ni2+ ions kutali OER kakunyina cyclohexone. Aboobo, kutanta kwa Ni2+ mu LSV curve kuli anguzu kwiinda kwa NiV-LDH-NS, kutondezya kuti kucinca kwa V kupa NiV-LDH-NS nguzu zyakubambulula (Langa Supplementary Fig. 19 kuti ujane buvwuntauzi buzulide).
a In situ Raman spectra ya Ni(OH)2-NS (kulumwensyi) antoomwe a NiV-LDH-NS (kululyo) muchiimo cha OCP musule akubikkwa kwa 1.5 VRHE mu 0.5 M KOH antoomwe a 0.4 M cyclohexanone kwa 60 s. b In situ Raman spectra ya Ni(OH)2-NS a c NiV-LDH-NS mu 0.5 M KOH + 0.4 M cyclohexanone aanguzu ziindene. d In situ XANES spectra of Ni(OH)2-NS and NiV-LDH-NS at Ni K-edge in 0.5 M KOH and e 0.5 M KOH and 0.4 M cyclohexanone. Chitondeezyo chitondeezya busena bupati akati ka 8342 a 8446 eV. f Ziimo zya Ni mu Ni(OH)2-NS a NiV-LDH-NS aamanguzu aasiyene. g In situ Ni EXAFS spectra ya NiV-LDH-NS kakutanaba akumana kubikkwa kwa cyclohexanone aamanguzu aasiyene. h Nzila zyakuyeeyela zya Ni(OH)2-NS antoomwe a NiV-LDH-NS. Kujulu: A Ni(OH)2-NS, kusanduka kwakufwambaana kuzwa ku Ni(OH)2-NS kuya ku NiOOH kubeleka mbuli RDS, mpawo cyclohexanone ilagwisya musyobo wa Ni uujisi nguzu kapati kwiinda munzila zyamakemikalu kutegwa uzumanane kuba a Ni uujisi nguzu zisyoonto kutegwa azwe AA. Munsi: A NiV-LDH-NS, ntaamu yakubambulula ilagwasyilizyigwa akusanduka kwa V, eezi zipa kuti RDS izwe kunzila yakubambulula kuya kunzila yamakemikalu. i Nguzu zya Gibbs zyaangulukide zilasanduka aawo Ni(OH)2-NS a NiV-LDH-NS niyakabambululwa. Data iitakwe mulimo ya aj a i ilapegwa mufailo lya data iitakwe mulimo.
Kuvwuntauzya kusanduka kwazibeela zya atomu azyamagesi muchiindi chakucheya kwa catalyst, twakachita in situ X-ray absorption spectroscopy (XAS) experiments, eezyo zyakapa chibelesyo changuzu chakuvwuntauzya kusanduka kwa Ni species munzila zyotatwe zitobelana: OER, cyclohexanone injection, antoomwe a COR at open circuit (OCP). Cifwanikiso chitondeezya K-edge XANES spectra ya Ni akuyungizya nguzu kakutanaba akujaigwa kwa cyclohexanone (Chitondeezyo 3d, e). Aawo mpawo, nguzu zyakunyona zya NiV-LDH-NS zili kabotu kwiinda zya Ni(OH)2-NS (Chitondeezyo 3d, e, mukati). Mweelwe waakati-kati wa Ni mubukkale buli boonse wakayeeyelwa kwiinda mukusanganya kwa XANES spectra akujokela musule kwa Ni K-edge absorption energy shift (Chitondeezyo 3f), antoomwe a spectrum yakatolwa kuzwa mumabbuku aakamwaigwa (Cifwanikiso Cakuyungizya 23)43.
Munzila yakusaanguna (kakutanaba kunjizigwa kwa cyclohexanone, kweendelana anzila ya OER; Cifwanikiso 3f, kulumwensyi), aanguzu zya catalyst iitakabambwa (<1.3 VRHE), chiimo cha Ni mu NiV-LDH-NS (+1.83) chili munsi-munsi a Ni(OH)2-NS (+197), eecho chikonzya kugwisigwa kuzwa ku V kuya ku electron kuya ku V. Ni, kweendelana azintu zyaambwa atala aawa zya XPS (Chitondeezyo 2f). Eelyo nguzu noziinda aawo mpozigolela (1.5 VRHE), chiimo cha Ni mu NiV-LDH-NS (+3.28) chitondezya kuyungizigwa kupati kweelanisigwa a Ni(OH)2-NS (+2.49). Aawo mpokugolela kapati (1.8 VRHE), chiimo cha NiV-LDH-NS (+3.64) chilisumpukide kwiinda Ni(OH)2-NS (+3.47). Kweelana amalipooti alino-lino, eeyi nzila yeendelana akupangwa kwamusyobo wa Ni4+ uujisi nguzu kapati mubupange bwa Ni3+xOOH1-x (Ni3+x nimusyobo uusanganizidwe wa Ni3+ a Ni4+), walo wakatondezya kale mulimo wakugwasya mukugusya maanzi mumubili38,39,44. Aboobo, kubeleka kabotu kwa NiV-LDH-NS mu COR inga kwaba akaambo kakuyungizigwa kwakucheya kwakupanga misyobo ya Ni iibeleka loko.
Munzila yabili (kutalisya cyclohexanone nikwakamana kujalulwa kwa ringi, Cifwanikiso 3f), chiimo cha Ni kulizyoonse zyobile zyakaseluka loko, eezi zyeendelana anzila yakugwisya Ni3+xOOH1-x a cyclohexanone, eezyo zyeendelana azyakazwa mu in situ Raman spectroscopy (Chitondeezyo 3), mpawo chiimo cha Ni chakali afwaafwi kujokela kuchiimo cha Ni3+xOOH1-x (ntaamu yakusaanguna aamanguzu masyoonto), kutondezya kujokoloka kwa nzila ya redox ya Ni kuya ku Ni3+xOOH1-x.
Munzila yatatu (COR process) ku COR potentials (1.5 a 1.8 VRHE; Cifwanikiso 3f, kululyo), chiimo cha Ni mu Ni(OH)2-NS chakatanta mbichani (+2.16 a +2.40), eecho chili munsi kapati kwiinda aanguzu zyomwe muntaamu yakusaanguna (+2.49 a +3.47). Eezyi mpindu zitondezya kuti nikwakamana kujaigwa kwa cyclohexanone, COR ilalesyegwa akusanduka kwa Ni2+ kuya ku Ni3+x (nkokuti, kuyakululwa kwa Ni) kwiinda ntaamu yamakemikalu aakati ka NiOOH a cyclohexanone a Ni(OH)2-NS, eeyo isiya Ni muchiimo cha low-valence. Aboobo, twamanizya kuti kuyakulula Ni kulakonzya kubeleka mbuli RDS munzila ya COR a Ni(OH)2-NS. Mukwiimpana, NiV-LDH-NS yakabamba mweelwe mupati wa Ni species (>3) muchiindi cha COR, mpawo mweelwe wakaselemuka asyoonto (ansi aa 0.2) kweelanisigwa antaamu yakusaanguna aanguzu zyeelene (1.65 a 1.8 VRHE), kutondezya kuti kucinca kwa V kwakasumpula oxidation ya Ni2+ kuya ku Ni2+, akufwambaana kwiinda Ni ntaamu yamakemikalu yakugwisya cyclohexanone. Ikuyungizya kwa X-ray absorption fine structure (EXAFS) yakatondeezya kusanduka koonse kwa Ni-O (kuzwa ku 1.6 kusika ku 1.4 Å) antoomwe a Ni-Ni(V) (kuzwa ku 2.8 kusika ku 2.4 Å) zijatikizyo kakuli cyclohexanone. Eezi zileendelana akuyakululwa kwa Ni(OH)2 phase kuya ku NiOOH phase akucheya kwa NiOOH phase a cyclohexanone (Fig. 3g). Nokuba boobo, cyclohexanone yakasinkila kapati kucesya kwa Ni(OH)2-NS (Langa Supplementary Note 4 a Supplementary Fig. 24 kuti ujane makani manji).
Kuzulilwa antoomwe, a Ni(OH)2-NS (Fig. 3h, atala), ntaamu yakucesya kuzwa ku Ni(OH)2 kuya ku NiOOH ilakonzya kubeleka mbuli RDS ya COR yoonse kutali ntaamu yakupanga AA kuzwa ku cyclohexanone muchiindi chakucheya kwa NiOOH. A NiV-LDH-NS (Mufanikisyo 3h, munsi), kuchincha kwa V kusumpula kweenda kwa Ni2+ kusika ku Ni3+x, aboobo kufwambaanya kupanga kwa NiVOOH (muciindi chakubelesyegwa kwiinda mukucesya misamu), eecho chisandula RDS kuya kunzila yamakkemikalu. Kuti tumvwisisisye kuyakululwa kwa Ni kwakachitwa akusanduka kwa V, twakachita zimwi zyakubala. Mbuli mbokutondezyedwe achifanikisyo 3h, twakakozyanisya nzila yakuyakulula Ni(OH)2-NS antoomwe a NiV-LDH-NS. Tubunga twa lattice hydroxyl tuli a Ni(OH)2-NS antoomwe a NiV-LDH-NS tulagwisyigwa kwiinda mukugwisya OH- mu electrolyte kuti tupange lattice oxygen iitakwe ma electron. Ikusanduka kwamakemikalu kweendelana kuliboobu:
Kuchincha kwanguzu zya Gibbs zyakuyakulula kwakabalilwa (Mufanikisyo 3i), mpawo NiV-LDH-NS (0.81 eV) yakatondezya kucinca kwanguzu zya Gibbs nsyoonto kwiinda Ni(OH)2-NS (1.66 eV), kutondezya kuti kucinca kwa V kwakacesya nguzu zyakali kuyandika mukubamba Ni. Tusyoma kuti kusumpula kuyakulula kulakonzya kucesya nguzu zya COR yoonse (langa chiiyo cha nzila zyakusanduka zili munsi aawa kuti ujane makani woonse), aboobo kufwambaanya kusanduka aawo mpaali manguzu manji.
Buvwuntauzi buli atala aawa butondezya kuti kuchincha kwa V kupa kuti Ni(OH)2 ichinche chakufwambaana, aboobo eezi ziyungizya mweelwe wakusanduka, mpawo, COR current density. Nokuba boobo, masena aa Ni3+x alakonzya kusumpula mulimo wa OER. Kuzwa ku LSV curve kakunyina cyclohexanone, chilisalede kuti bunji bwa NiV-LDH-NS bulisumpukide kwiinda bwa Ni(OH)2-NS (Supplementary Fig. 19), eecho chipa kuti COR a OER zibe nzila zyakuzundana. Aboobo, FE mpati loko ya AA kwiinda ya NiV-LDH-NS taikonzyi kupandululwa pe akusanduka kwa V ikusumpula kubamba zibeela.
Chilizuminwa kuti mubukkale bwa alkaline, nzila zya electrooxidation zya nucleophilic substrates zitobela nzila ya Langmuir-Hinshelwood (LH). Mubwini, substrate antoomwe a OH− anions zilazundana antoomwe atala aa catalyst, mpawo OH− yakayungizigwa ilasanduka kuba tubunga twa hydroxyl (OH*), ooto tubeleka mbuli ma electrophiles mu oxidation ya nucleophiles, nzila yakatondezyegwa kale kwiinda mu data yakusola alimwi/naakuti zyakubala, 4444. Aboobo, bunji bwazintu zipangwa antoomwe amweelwe wazyo (zintu zipona a OH−) zilakonzya kweendelezya kuvwumbililwa kwazintu zipangwa atala aa catalyst, aboobo zilakonzya kugwasya FE akuzyala kwachintu chiyanda kubelesegwa14,48,49,50. Muchiimo chesu, twayeyela kuti kuvwumbililwa kwa cyclohexanone kupati mu NiV-LDH-NS kulagwasya nzila ya COR, mpawo, kuvwumbililwa kwa cyclohexanone kusyoonto mu Ni(OH)2-NS kulagwasya nzila ya OER.
Kusunka muzeezo uuli atala aawa, twakasaanguna kuchita mibandi yobile iijatikizya bunji bwazintu zibeleka (C, cyclohexanone, a COH−). Kusunka kutaanzi kwakachitwa a electrolysis aanguzu zitacinci (1.8 VRHE) a Ni(OH)2-NS a NiV-LDH-NS catalysts a cyclohexanone C yiindene (0.05 ~ 0.45 M) antoomwe a COH− iitacinci (0.5 M). Mpawo, FE antoomwe a AA zyakabalilwa. Ku NiV-LDH-NS catalyst, kujatana aakati ka AA yield a cyclohexanone C kwakatondezya "volcanic type" curve munzila ya LH (Fig. 4a), kutondezya kuti cyclohexanone mpati ilazundana a OH− adsorption. Aawo kuli Ni(OH)2-NS, mweelwe wa AA wakatanta biyo akutanta kwa C ya cyclohexanone kuzwa ku 0.05 kusika ku 0.45 M, kutondezya kuti nikuba kuti bunji bwa cyclohexanone bwakali bupati (0.45 M), busena bwayo bwakali buniini. Mukuyungizya, akuyungizigwa kwa COH− kusika ku 1.5 M, "musyobo wamulilo" wakabonwa a Ni(OH)2-NS kweendelanya a C ya cyclohexanone, mpawo aawo mpokugolela kwakubeleka kwakaceedezyegwa kweelanisigwa a NiV-LDH-NS, kutondezya kuti cyclohexanone tiikwakali kunjila kabotu a NiV-LDH-NS (25). a Note 5). Mukuyungizya, FE ya AA a NiV-LDH-NS yakalikuchiimo cha C-cyclohexanone mpawo yakatanta chakufwambaana kusika ku 80% aawo C-cyclohexanone niyakayungizigwa kuzwa ku 0.05 M kusika ku 0.3 M, kutondezya kuti cyclohexanone yakavwubidwe a NiV-LDH-NS (Mufanikisyo 4b). Mukwiimpana, kuyungizya bunji bwa C-cyclohexanone tiikwakakasya OER a Ni(OH)2-NS, eezi zilakonzya kuba akaambo kakutazula kwa cyclohexanone. Mukukazyanya, kuyanduulisisya kunembo kwakusyoma kwa COH− akubeleka kabotu kwakasinizya kuti kunjila kwa cyclohexanone kwakasumpuka kweelanisigwa a NiV-LDH-NS, eeyo yakali kukonzya kuliyumya COH− mpati muchiindi cha COR kakunyina kucesya FE ya AA (Supplementary Fig. 25b, c and Note 5).
Kuzwidilila kwa AA a EF ya b Ni(OH)2-NS a NiV-LDH-NS a cyclohexanone a C yiindene mu 0.5 M KOH. c Nguzu zyakunjila zya cyclohexanone a NiOOH a NiVOOH. d FE ya AA a Ni(OH)2-NS antoomwe a NiV-LDH-NS mu 0.5 M KOH a 0.4 M cyclohexanone a 1.80 VRHE kubelesya nzila zitazumanani alimwi zitacinci. Mibala yakulubizya yiiminina kusiyana kwazyeelelo zyotatwe zitabelesyegwi kubelesya musamu omwe mpawo zili mukati ka 10%. e Kujulu: A Ni(OH)2-NS, cyclohexanone iijisi busena busyoonto bwa C ilajatikizyigwa a cyclohexanone, eezi zipa kuti kube kuzundana kupati kwa OER. Munsi: A NiV-LDH-NS, busena bupati bwa cyclohexanone C bwakabonwa antoomwe akuyungizya kunjila kwa cyclohexanone, eezi zyakapa kuti OER ilesyegwe. Data iitakwe mulimo ya a-d ilapegwa mufailo lya data iitakwe mulimo.
Kusunka kuyungizigwa kwakunjilila kwa cyclohexanone a NiV-LDH-NS, twakabelesya electrochemical coupled quartz crystal microbalance (E-QCM) kulanga kuchincha kwabunji bwazintu zyakanjililwa muchiindi cheenzu. Izyazwa zyakatondezya kuti nguzu zyakusaanguna zya cyclohexanone a NiV-LDH-NS zyakali zipati ziindi zili 1.6 kwiinda Ni(OH)2-NS muchiimo cha OCP, mpawo ooku kwiimpana kwanguzu zyakunjila kwakayungizyika aawo nguzu nizyakatanta kusika ku 1.5 VRHE (Supplementary Fig. 26). Kubalila kwa Spin-polarized DFT kwakachitwa kuti kuvwuntauzyigwe nzila yakunjila kwa cyclohexanone a NiOOH a NiVOOH (Chitondeezyo 4c). Cyclohexanone ilanjila mu Ni-center a NiOOH anguzu zyakunjilila (Eads) zya -0.57 eV, mpawo cyclohexanone ilakonzya kunjila mu Ni-center naa V-center a NiVOOH, ooko V-center nkoipa Eads nsyoonto kapati (-0.69 eV), kweendelana anguzu zyakunjilila zyabonwa cyclohexanone a NiVOOH.
Kuyungizya kusinizya kuti kuyungizigwa kwa cyclohexanone kulakonzya kusumpula kupanga kwa AA akulesya OER, twakabelesya nzila iitamani yakuyungizya cyclohexanone atala aa catalyst (ku Ni(OH)2-NS a NiV-LDH-NS), eeyo yakasololelwa amalipooti aakaindi. 51, 52 Mubwini, twakabelesya nguzu zya 1.8 VRHE ku COR, mpawo twakachincha kuya kuchiimo cha OCP, mpawo twakachincha alimwi ku 1.8 VRHE. Muchiimo eechi, cyclohexanone ilakonzya kuyoboloka atala aa catalyst muchiimo cha OCP aakati ka electrolyses (Langa nzila zyakubelesya kuti ujane nzila zyiingi). Izyazwa zyakatondezya kuti kuli Ni(OH)2-NS antoomwe a NiV-LDH-NS, kubelesya nguzu zya magesi zitazumanani kwakasumpula mulimo wa catalytic kweelanisigwa akubelesya magesi aatakonzyi kuzumanana (Chitondeezyo 4d). Chazibinkene, Ni(OH)2-NS yakatondezya kusumpuka kupati mu COR (AA FE: kuzwa ku 51% kusika ku 82%) akulesyegwa kwa OER (O2 FE: kuzwa ku 27% kusika ku 4%) kwiinda NiV-LDH-NS, eecho chakachitika akaambo kakuti kuyoboloka kwa cyclohexanone kwakali kukonzya kusumpulwa kapati a cataker, Ni(OH)2-NS) kwiinda mukubelesya nguzu zya magesi.
Kuzulilwa antoomwe, kukasyigwa kwa OER a NiV-LDH-NS kulakonzya kwaambwa kuti kwayungizyigwa kunjila kwa cyclohexanone (Chitondeezyo 4e). Aa Ni(OH)2-NS (Mufanikisyo 4e, atala), kubula nguzu kwa cyclohexanone kwakapa kuti kube kuvwumbilila kwa cyclohexanone kusyoonto alimwi akuvwumbililwa kwa OH* kupati atala aa catalyst. Aboobo, misyobo ya OH* iinda aawo iyoopa kuti kube kuzundana kupati kwa OER akucesya FE ya AA. Mukwiimpana, a NiV-LDH-NS (Mufanikisyo 4e, munsi), kucinca kwa V kwakayungizya nguzu zyakunjila kwa cyclohexanone, aboobo kwakayungizya busena bwa C bwa cyclohexanone akubelesya kabotu musyobo wa OH* wakanjililwa mu COR, kusumpula kupanga AA akulesya OER.
Mukuyungizya mukulanga-langa mpindu yakucinca kwa V mukuyakulula misyobo ya Ni akunjila kwa cyclohexanone, twakavwuntauzya akuti naa V ilachincha nzila yakupanga AA kuzwa ku COR. Nzila zyiingi zya COR zyakaambwa mumabbuku, mpawo twakalanga-langa mbozikonzya kuchitwa munzila yesu yakusandula (Langa Supplementary Fig. 27 a Supplementary Note 6 kuti ujane makani manji)13,14,26. Chakusanguna, kwakaambwa kuti ntaamu yakusaanguna yanzila ya COR ilakonzya kujatikizya kusanguna kwa cyclohexanone kuti ipange 2-hydroxycyclohexanone (2)13,14. Kusinizya nzila, twakabelesya 5,5-dimethyl-1-pyrrolidine N-oxide (DMPO) kujata zintu zili akati-akati zyakajatikizyigwa atala aa catalyst mpawo twakayiya EPR. Izyazwa mu EPR zyakayubununa kubako kwa C-centred radicals (R ) antoomwe a hydroxyl radicals (OH ) kulizyoonse zyobile zyeendelezya muchiindi cha COR, kutondeezya kuti Cα − H dehydrogenation ya cyclohexanone yakapanga enolate radical (1), eeyo yakayungizigwa a OH* kuti ipange 2 (Fig. 5 a Supplement 28). Nikuba kuti zintu zili akati-akati zyakajanika kulizyoonse zyobile, busena bwa R signal a NiV-LDH-NS bwakali bupati kwiinda bwa Ni(OH)2-NS, eezyo zinga zyaba akaambo kakuyungizigwa kwanguzu zya cyclohexanone (Supplementary Table 3 and Note 7). Twakabelesya 2 antoomwe a 1,2-cyclohexanedione (3) mbuli zintu zyakutalisya zyakubelesya magesi kuti tusunke naa V ulakonzya kuchincha ntaamu ya oxidation iitobela. Izyazwa mu electrolysis yazyintu zikonzya kuba akati-kati (2 a 3) a Ni(OH)2-NS a NiV-LDH-NS zyakatondezya kusala kwazintu zyeelene, kutondezya kuti COR reaction a Ni(OH)2-NS naa NiV-LDH-NS yakachitika munzila zikozyenye (Chitondeezyo 5b). Kwiindawo, AA yakali chintu chipati biyo aawo 2 niyakabelesegwa mbuli chintu, kutondeezya kuti AA yakajanwa kwiinda mukubelesya nzila yakugwisya muya kwiinda mukukosolwa kwa Cα − Cβ bond ya 2 kwiinda mukusanduka kuya ku 3 kuli zyoonse zyobile, nkaambo yakasandulwa kuba GA aawo 3 niyakabelesegwa mbuli chintu chakutalika (Sifwanikiso, 29 30).
EPR signal ya NiV-LDH-NS mu 0.5 M KOH + 0.4 M cyclohexanone. b Zyakazwa mukuvwuntauzya kwa 2-hydroxycyclohexanone (2) antoomwe a 1,2-cyclohexanedione (3). Kusanzya magesi kwakachitwa mu 0.5 M KOH a 0.1 M 2 naa 3 a 1.8 VRE kwawoola lyomwe. Mibala yakulubizya yiiminina kusiyana kwazyeelelo zyobile zitabelesyegwi kubelesya chintu chomwe. c Nzila zyakusanduka zya COR zyakayeeyelwa aatala azibelesyo zyobile. d Cifwanikiso cha COR pathway a Ni(OH)2-NS (kulumwensyi) a d NiV-LDH-NS (kululyo). Mivwi iisalala pyu itondezya ntaamu eezyo kucinca kwa V nkwasumpula munzila ya COR. Data iitakwe mulimo ya a a b ilapegwa mufailo lya data iitakwe mulimo.
Kuzulilwa antoomwe, twakatondezya kuti Ni(OH)2-NS antoomwe a NiV-LDH-NS zipa kuti COR ichite kabotu kwiinda munzila iikozyenye: cyclohexanone ilanjililwa atala aa catalyst, ilagwisigwa maanzi mpawo ilasweekelwa ma electron kuti ipange 1, eeyo mpawo yasandulwa a OH* kuti ipange 2, mpawo yakatobelwa akusanduka kwazibeela zyiingi kuti ipange (Figure AAc 5). Nokuba boobo, aawo cyclohexanone niyakabelesegwa mbuli chintu chibeleka, kuzundana kwa OER kwakabonwa buyo a Ni(OH)2-NS, mpawo mweelwe musyoonto wa oxygen wakayobolwa aawo 2 a 3 nibakabelesegwa mbuli chintu chibeleka. Aboobo, kwiimpana kwakabonwa mukubeleka kwa catalytic kulakonzya kuba akaambo kakucinca kwa RDS energy barrier antoomwe a cyclohexanone adsorption capacity yakaletwa akusanduka kwa V kutali kucinca kwanzila yakusanduka. Aboobo twakavwuntauzya RDS yanzila zyakusanduka kuli zyoonse zyobile. Zyakazwa mu X-ray acoustic spectroscopy zyaambwa atala aawa zitondezya kuti kuchincha kwa V kwasandula RDS mu COR kuzwa kuchiimo chakuyakulula kuya kuchiimo chamakemikalu, akubamba NiOOH phase antoomwe a high-valent Ni species kuti kiitakwe ntenda a NiV-LDH-NS (Fig. 3f, Supplementary Fig. 24, Note Note 44). Twakayungizya kulanga-langa nzila zyakusanduka zyakali kwiimininwa abulemu bwamazubaano muchibeela chimwi achimwi chamasena aasiyene-siyene aakonzya kubelesegwa muchiindi chakupima CV (Langa Supplementary Fig. 31 a Note 8 kuti ujane makani woonse) mpawo twakachita H/D kinetic isotope exchange experiments, eezyo zyakatondezya kuti RDS ya COR a NiV-LDH-NS ilabikkilizya H chiimo chamakemikalu kutali chiimo chakucesya (Langa Supplementary Fig. 32 a Note 8 kuti ujane makani manji).
Kwiinda mukulanga-langa kwakacitwa atala aawa, mpindu yoonse yakucinca kwa V itondezyedwe muchifanikisyo 5d. Ni(OH)2-NS antoomwe a NiV-LDH-NS zibelesyo zipa kuti kube kuyakululwa kwaatala aa anodic potentials mpawo zipa kuti COR ibelesegwe munzila iikozyenye. A Ni(OH)2-NS (Mufanikisyo 5d, kulumwensyi), ntaamu yakuyakulula nja RDS muchiindi cha COR; mpawo a NiV-LDH-NS (Mufanikisyo 5d, kululyo), kucinca kwa V kwakafwambaanya nzila yakuyakulula mpawo kwakasandula RDS kuba Cα−H dehydrogenation ya cyclohexanone kuti ibe 1. Mukuyungizya, cyclohexanone yakayungizigwa a NiV-LDH-NS, eeyo yakagwasya mukulesya OER.
Twalanga-langa mulimo mubotu wa NiV-LDH-NS uujisi FE mpati kwiinda mukubelesya nguzu zinji, twakabamba MEA kutegwa tuzumanane kupanga AA. MEA yakabungikwa kubelesya NiV-LDH-NS mbuli anode, PtRu/C yamakwebo mbuli cathode53 antoomwe a anion exchange membrane (musyobo: FAA-3-50) (Chitondeezyo 6a aChitondeezyo Chakuyungizya 33)54. Mbwaanga nguzu zyamaseelo zyakaseluka mpawo FE ya AA yakalikozyenye a 0.5 M KOH muchiiyo chili atala aawa, bunji bwa anolyte bwakasumpulwa kusika ku 1 M KOH (Supplementary Fig. 25c). Ma LSV aalembedwe atondezyedwe mu Supplementary Fig. 34, kutondezya kuti COR efficiency ya NiV-LDH-NS ilisumpukide kwiinda Ni(OH)2-NS. Kutondezya bubotu bwa NiV-LDH-NS, nzila yakubelesya magesi iitacinci yakachitwa a step current density kuzwa ku 50 kusika ku 500 mA cm−2 mpawo nguzu zya cell zyakalembwa. Izyazwa zyakatondezya kuti NiV-LDH-NS yakatondezya nguzu zya 1.76 V a 300 mA cm−2, eezyo zyakali munsi a 16% kwiinda Ni(OH)2-NS (2.09 V), kutondezya kuti zyakali kubelesya manguzu manji mukupanga AA (Fig. 6b).
Cifwanikiso cha bbattery lyakuzuza. b Manguzu aamaseelo kakunyina kuvwola kwa iR a Ni(OH)2-NS a NiV-LDH-NS mu 1 M KOH a 0.4 M cyclohexanone aama current densities aasiyene. c AA a FE zizyala a Ni(OH)2-NS antoomwe a NiV-LDH-NS aamanguzu aasiyene. Mibala yakulubizya yiiminina kusiyana kwazyeelelo zyobile zitabelesyegwi kubelesya chintu chomwe. d Kweezyanisya kwakubeleka kwamulimo wesu azimwi zibelesyo zyamabbattery14,17,19. Izyeelelo zyakusanduka abukkale bwakusanduka zililembedwe mubufwaafwi mu Supplementary Table 2. e Manguzu aamaseelo a FE ya AA a NiV-LDH-NS a 200 a 300 mA cm−2 mukusunkwa kwachiindi chilamfu, kweendelana. Data iitabelesyegwi pe ilapegwa mbuli fayela lya data iitabelesyegwi pe.
Muchiindi eecho, mbuli mbokutondezyedwe muchifanikisyo 6c, NiV-LDH-NS yakabamba FE mbotu (83% kusika ku 61%) aanguzu zyamagesi zisumpukide (200 kusika ku 500 mA cm-2), aboobo yakasumpula mulimo wa AA (1031 kusika ku 1900 μmol cm-2 h-1). Muchiindi eecho, buyo 0.8% ya adipic acid anions yakabonwa muchibeela cha cathode nikwakamana kugwisigwa magesi, kutondezya kuti kucinca kwa cyclohexanone tiikwakali kuyandika pe muchiimo chesu (Supplementary Fig. 35). Mukwiimpana, amweelwe uukozyenye wakuyungizya nguzu zyamagesi, FE ya AA a Ni(OH)2-NS yakaselemuka kuzwa ku 61% kusika ku 34%, eecho chakapa kuti kakutazya kusumpula buvwubi bwa AA (762 kusika ku 1050 μmol cm-2 h-1). Mubwini, kubeleka kwa AA kwakaceya mbichani akaambo kakuzundana kupati kuzwa kuli OER, aboobo FE ya AA yakaselemuka loko akuyungizya kwabunji bwamazubaano (kuzwa ku 200 kusika ku 250 mA cm−2, Supplementary Fig. 5). Kweelana aluzibo ndotujisi, mpindu zyakubelesya MEA a NiV-LDH-NS catalysts zilainda kapati kubeleka kwa flow reactors zyakaambwa musyule a Ni-based catalysts (Supplementary Table 2). Kwiindawo, mbuli mbokutondezyedwe muchifanikisyo 6d, NiV-LDH-NS yakatondezya bubotu bupati mumakani aanguzu zyamagesi, nguzu zyamaselu, antoomwe aFE ya AA kweelanisigwa a Co-based catalyst iibeleka kabotu, nkokuti, graphene-supported Co3O4 (Co3O4/GDY)17. Mukuyungizya, twakalanga-langa kubelesya manguzu mukupanga AA mpawo twakatondezya kuti kubelesya kwa AA kwakali kusyoonto loko, 2.4 W h gAA-1 biyo a 300 mA cm-2 a cell voltage ya 1.76 V (kubala kwakacitwa mu Supplementary Note 1). Kweezyanisya achiimo chibotu cha 4.1 W h gAA-1 ya Co3O4/GDY yakaambwa musule, kubelesya manguzu mukupanga AA mumulimo wesu kwakacheya a 42% mpawo buvwubi bwakayungizigwa ziindi zyone (1536 vs. 319 μmol cm-2 h-1)17.
Kukkalilila kwa NiV-LDH-NS catalyst ya AA yachiindi chilamfu mu MEA kwakali kulinguwe a 200 a 300 mA cm-2, kweendelana (Chitondeezyo 6e). Mbwaanga OH− ilafwambaana kubelesyegwa aawo manguzu manji, mweelwe wakubukulusya magesi a 300 mA cm-2 ulisumpukide kwiinda a 200 mA cm-2 (langa kabeela kaniini "Kupima kwamagesi" kuti ujane makani woonse). Aawo mpoili 200 mA cm-2, mweelwe waakati-kati wa COR wakali 93% mumahola aakusaanguna aali 6, mpawo wakaseluka kusika ku 81% musule lya 60 h, mpawo nguzu zyamaseelo zyakatanta asyoonto a 7% (kuzwa ku 1.62 V kusika ku 1.73 V), kutondezya kukkalikana kubotu. Aawo nguzu zyamagesi nizyakali kuyaa kuyungizyika kusika ku 300 mA cm−2, kubeleka kabotu kwa AA kwakazumanana kutachincha pe (kwakaselemuka kuzwa ku 85% kusika ku 72%), asi nguzu zyamagesi zyakatanta kapati (kuzwa ku 1.71 kusika ku 2.09 V, kweendelana a 22%) muchiindi cha 46-h test (Chitondeezyo 6). Tuyeeyela kuti kaambo kapati kakunyonyooka kwakubeleka nkubola kwa anion exchange membrane (AEM) a cyclohexanone, ooko kuleta kuyungizigwa kwakukazyigwa kwamaseelo anguzu zya electrolyzer cell (Supplementary Fig. 36), antoomwe akuvwundauka kusyoonto kwa electrolyte kuzwa ku anode kuya ku cathode, eezi zipa kuti kucheya kwakuyandika kwa anode kusandula magesi. Mukuyungizya, ikucheya kwa FE ya AA kulakonzya kuba akaambo kakuzwa kwama catalysts, ooko kugwasya kujalulwa kwa Ni foam ya OER. Kutondezya lugwasyo lwa AEM yakabola kukunyonyooka kwakukkalikana a 300 mA cm−2, twakabikka AEM mpya musule lya 46 h ya electrolysis. Mbuli mbukwakalangililwa, kubeleka kabotu kwakajokezyegwa, aawo manguzu aamaseelo akaselemuka kusika aawo mpoakali kumatalikilo (kuzwa ku 2.09 kusika ku 1.71 V) mpawo akuyungizya mbichaani muchiindi cha 12 h cha electrolysis (kuzwa ku 1.71 kusika ku 1.79 V, kuyungizigwa kwa 5%; Cifwanikiso 6e).
Kuzulilwa antoomwe, twakakonzya kuzuzikizya 60 h ya AA iizumanana kukkalwa moyo a 200 mA cm−2, kutondezya kuti FE a cell voltage ya AA zilalanganizigwa obotu. Twakasola alubo kubelesya nguzu zya 300 mA cm−2 mpawo twakajana kukkalikana kwa 58 h, mpawo twabikka AEM mpya musule lya 46 h. Ziiyo zili atala aawa zitondezya kukkalikana kwa catalyst mpawo zitondezya antangalala mbokuyandika kuyaambele kwa AEMs zyanguzu zyiingi kuchitila kuti MEA izumanane kukkalwa moyo muchiindi chilamfu.
Kwiinda mukubeleka kwa MEA yesu, twakakankaizya nzila yakupanga AA iizulide kubikkilizya akulya kwa substrate, electrolysis, neutralization, antoomwe a separation units (Supplementary Fig. 37). Kuvwuntauzya kwakusaanguna kwakachitwa kuti kubone naa nzila eeyi ilakonzya kubeleka kabotu kwiinda mukubelesya nzila yakupanga magesi aajisi busani bwa alkaline electrolyte55. Muchiimo eechi, mali abelesyegwa abikkilizya mali, milimu, azibelesyo (Mufanikisyo 7a aMufanikisyo Uuyungizyidwe 38), mpawo mali azwa mukupanga AA a H2. Izyazwa mu TEA zitondezya kuti muchiimo chesu chakubeleka (kuyuma kwa 300 mA cm-2, manguzu aamaseelo 1.76 V, FE 82%), mali oonse aasangwa a US$2429 antoomwe a US$2564, kweendelana, kusandulula mpindu ya US$135 ku toni lyomwe lya AA lyakapangwa (Langa Supplement Note 9 kuti ujane makani woonse).
a Muulo woonse wa AA electrochemical process muchiimo chakusaanguna a FE ya 82%, current density ya 300 mA cm−2, antoomwe a cell voltage ya 1.76 V. Kuvwuntauzya kwa sensitivity kwa miulo yotatwe kuli b FE a c current density. Mukulanga-langa kwakumvwisisisya, buyo zibeela zyakavwuntauzyigwa zyakasandulwa mpawo zimwi zibeela zyakazumanana kweendelanya a TEA model. d Ikujatikizyigwa kwa FE ziindene-indene abulemu bwamagesi aa AA electrosynthesis alimwi ampindu yakubelesya Ni(OH)2-NS a NiV-LDH-NS, kakuyeeyelwa kuti magesi aaseelo alazumanana kuba a 1.76 V. Data yakunjizya ya a–d ilapegwa mufailo lya data litakwe mulimo.
Kwiinda muchiimo eechi, twakayungizya kuyanduulisisya aatala akugwasya kwa FE a current density mukujana mpindu ya AA electrosynthesis. Twakajana kuti mpindu ilabikkila maano kapati ku FE ya AA, nkaambo kucesya kwa FE kuletela kuyungizigwa kupati kwamali aabelesyegwa, aboobo akuyungizya kapati muulo woonse (Mufanikisyo 7b). Kujatikizya bunji bwamagesi, bupati bwamagesi bupati (>200 mA cm-2) bulagwasya kucesya mali aabelesyegwa alimwi amali aakuyaka ŋanda, ikapati kwiinda mukucesya busena bwamaseelo aabelesya magesi, aboobo akugwasya kuyungizya mpindu (Mufanikisyo 7c). Kweezyanisya abulemu buliwo lino, FE ilaampindu mpati mumpindu. Kwiinda mukulanga-langa lugwasyo lwa FE abulemu bwamazubaano kumpindu, tulabona antangalala mbociyandika kujana FE mpati (>60%) abulemu bwamazubaano bweelede mumakwebo (>200 mA cm-2) kuchitila kuti kube mpindu. Akaambo kakuti FE mpati ya AA, nzila yakusanduka a NiV-LDH-NS mbuli chitondeezyo ilazumanana kuba kabotu aakati ka 100–500 mA cm−2 (madoti aa pentagram; Cifwanikiso 7d). Nokuba boobo, kuli Ni(OH)2-NS, kucesya FE aanguzu zyamagesi zipati (>200 mA cm−2) kwakapa kuti kube mpindu zitali kabotu (zikobela; Cifwanikiso 7d), kutondezya mbociyandika zintu zipa kuti kube FE mpati aanguzu zyamagesi zipati.
Mukuyungizya kukuyandika kwazintu zipa kuti kube kuchita obotu mukucesya mali abelesyegwa, TEA yesu yakuvwuntauzya itondezya kuti mpindu ilakonzya kuyaambele munzila zyobile. Chakusanguna nchakusambala antoomwe potassium sulfate (K2SO4) mumusika mbuli chintu chizwa muchintu chakulesya, pesi amali aakonzya kusika ku US$828/t AA-1 (Supplementary Note 9). Cabili nkuchita kuti nzila zyakuchita zintu zibe kabotu, kubikkilizya akubelesya zintu zyakabelesegwa lubo naakuti kupanga nzila zitayandiki mali manji zyakwaandaanya AA (nzila zimbi zyakugwisya akwaandaanya). Nzila yakugwisya asidi-base iibelesyegwa lino ilakonzya kupa kuti zintu zibelesyegwe kapati (eezyo zipa kuti kube 85.3%), oomo 94% yazwa ku cyclohexanone a KOH ($2069/t AA-1; Cifwanikiso 7a), pele mbuli mbokwaambidwe atala aawa, nzila eeyi icili kugwasya kapati. Tulaamba kuti muulo wazintu ulakonzya kucheya kwiinda mukubelesya nzila zisumpukide zyakujana KOH antoomwe a cyclohexanone iitakwe nsandulo, mbuli electrodialysis kuti KOH14 ibwezegwe (muulo uuyeeyelwa kuti ngu US$1073/t AA-1 kwiinda mukubelesya electrodialysis; Supplementary Note 9).
Muchi chifwiifwi, twakajana kubeleka obotu kwa aluminiyamu atomu electrolysis a current density mpati kwiinda mukunjizya V muma Ni(OH)2 nanosheets. Muchiimo chilamfu cha 1.5-1.9 VRHE antoomwe a 170 mA cm−2, AA FE a NiV-LDH-NS yakasika ku 83-88%, mpawo OER yakasinkililwa kusika ku 3%. Kuchincha kwa V kwakasumpula kucheya kwa Ni2+ kusika ku Ni3+x mpawo kwasumpula kunjila kwa cyclohexanone. Data yakusola ayakuyeeyela itondezya kuti kuyakulula kwakasungwaazigwa kuyungizya bunji bwa cyclohexanone oxidation mpawo kwasandula RDS ya COR kuzwa kukuyakulula kuya ku dehydrogenation kujatikizya Cα − H scission, mpawo kuyungizigwa kwa cyclohexanone kulesya OER. Kusumpuka kwa MEA kwakapa kuti kube kupanga AA kuzumanana a 300 mA cm−2, AA efficiency ya 82%, antoomwe a 1536 μmol cm−2 h−1. Kusunkwa kwamahola aali makumi musanu kwakatondezya kuti NiV-LDH-NS ilakkalilila kabotu nkaambo ilakonzya kubamba AA FE mpati mu MEA (> 80% kwamawoola aali makumi musanu aatatu a 200 mA cm−2; > 70% kwamahola aali makumi musanu atutatwe a 300 mA cm−2). Chileelela kuzyibwa kuti kuyandika kupanga ma AEM manguzu loko kuchitila kuti kube kukkalwa moyo kwachiindi chilamfu aawo mpokugolela. Mukuyungizya, TEA itondezya bubotu bwakuvwola bwanzila zyakuchita zintu mukupanga AA akuyandika kwazibelesyo zibeleka obotu anzila zyakwaandaanya zisumpukide kuchitila kuti kube kuchesya mali.