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Mmepe nke teknụzụ hydrogen dị n'isi akụ na ụba akwụkwọ ndụ akwụkwọ ndụ. Dịka ihe dị mkpa maka imezu nchekwa hydrogen, a chọrọ ihe mkpali na-arụ ọrụ na nke kwụsiri ike maka mmeghachi omume hydrogenation (de) hydrogenation. Ruo ugbu a, ebe a ka ejiri ọla dị oke ọnụ ahịa chịkwaa. N'ebe a, anyị na-atụ aro ihe mkpali ọhụrụ nke dabere na cobalt dị ọnụ ala (Co-SAs/NPs@NC) ebe a na-ejikọta ebe otu metal nke kesara nke ukwuu na obere nanoparticles iji nweta mbelata acid formic dị irè. Site na iji ihe kacha mma nke nkeji CoN2C2 atomiki gbasaara na nanoparticles nke nha 7-8 nm, na-eji propylene carbonate dị ka ihe mgbaze, enwetara mmepụta gas dị mma nke 1403.8 ml g-1 h-1, enweghịkwa mfu ọ bụla mgbe usoro ise gasịrị. ọrụ, nke dị okpukpu 15 ka mma karịa Pd/C azụmahịa. Nnwale nnwale In situ na-egosi na, ma e jiri ya tụnyere atọm metal otu na ihe na-akpali nanoparticle, Co-SAs/NPs@NC na-eme ka adsorption na ọrụ nke isi monodentate intermediate HCOO* dịkwuo mma, si otú a na-akwalite nkewa njikọ CH na-esote. Ngụkọta echiche na-egosi na njikọta nke nanoparticles cobalt na-akwalite mgbanwe nke etiti d-band nke otu atọm Co ka ọ bụrụ ebe na-arụ ọrụ, si otú a na-eme ka njikọ dị n'etiti carbonyl O nke etiti HCOO* na etiti Co dịkwuo mma, si otú a na-ebelata ihe mgbochi ike.
A na-ewere hydrogen dị ka ihe na-ebu ike dị mkpa maka mgbanwe ike zuru ụwa ọnụ ugbu a, ọ pụkwara ịbụ ihe dị mkpa iji nweta nnọpụiche carbon1. N'ihi ihe ndị dị na ya dịka ire ọkụ na obere njupụta, nchekwa na mbufe hydrogen dị mma ma dị irè bụ isi ihe dị mkpa n'imezu akụ na ụba hydrogen2,3,4. Atụpụtala atụmatụ maka ihe ndị na-ebu hydrogen organic mmiri mmiri (LOHCs), bụ́ ndị na-echekwa ma na-ewepụta hydrogen site na mmeghachi omume kemịkalụ. Ma e jiri ya tụnyere hydrogen molecular, ihe ndị dị otú ahụ (methanol, toluene, dibenzyltoluene, wdg) dị mfe ma dịkwa mfe ijikwa5,6,7. N'etiti LOHC ọdịnala dị iche iche, formic acid (FA) nwere obere nsí (LD50: 1.8 g/kg) na ikike H2 nke 53 g/L ma ọ bụ 4.4 wt%. Nke pụtara ìhè bụ na FA bụ naanị LOHC nke nwere ike ịchekwa ma wepụta hydrogen n'okpuru ọnọdụ dị nro n'ihu ihe ndị na-akpali akpali kwesịrị ekwesị, ya mere ọ naghị achọ nnukwu ntinye ike mpụga1,8,9. N'eziokwu, e mepụtala ọtụtụ ihe na-akpali ígwè dị mma maka iwepụ mmiri mmiri nke formic acid, dịka ọmụmaatụ, ihe na-akpali ígwè dabere na palladium na-arụ ọrụ ugboro 50-200 karịa ihe na-akpali ígwè dị ọnụ ala10,11,12. Agbanyeghị, ọ bụrụ na ị tụlee ọnụ ahịa ígwè na-arụ ọrụ, dịka ọmụmaatụ, palladium dị oke ọnụ karịa ugboro 1000.
Cobalt, Nchọgharị maka ihe ndị na-akpali ígwè dị iche iche na-arụ ọrụ nke ọma ma kwụsie ike na-aga n'ihu na-adọta mmasị nke ọtụtụ ndị nchọpụta na agụmakwụkwọ na ụlọ ọrụ 13, 14, 15.
Ọ bụ ezie na ihe ndị na-akpali akpali dị ọnụ ala dabere na Mo na Co, yana nanocatalysts nke e ji ọla edo dị mma/base mee, 14,16 emepụtala maka iwepụ mmiri mmiri na FA, mana mwepụ ha nwayọ nwayọ n'oge mmeghachi omume a bụ ihe a na-apụghị izere ezere n'ihi na ha na-ejide ebe ndị na-arụ ọrụ nke ọla, CO2, na H2O site na protons. ma ọ bụ formate anions (HCOO-), mmetọ FA, nchịkọta ihe na nsi CO nwere ike ime17,18. Anyị na ndị ọzọ gosipụtara n'oge na-adịbeghị anya na ihe ndị na-akpali akpali otu atọm (SACs) nwere ebe CoIINx gbasaara nke ukwuu dị ka ebe ndị na-arụ ọrụ na-eme ka mmeghachi omume na nguzogide acid nke formic acid dehydrogenation dịkwuo mma ma e jiri ya tụnyere nanoparticles17,19,20,21,22,23,24. N'ihe ndị a na-emepụta Co-NC, atọm N na-arụ ọrụ dị ka ebe ndị bụ isi iji kwalite mwepụ mmiri na FA ebe ha na-eme ka nkwụsi ike nhazi dịkwuo mma site na nhazi na atọm Co etiti, ebe atọm Co na-enye ebe H adsorption ma na-akwalite mwepụ mmiri na CH22, 25,26. N'ụzọ dị mwute, ọrụ na nkwụsi ike nke ihe ndị a ka dị anya site na ihe ndị na-eme ka ígwè dị mma dị iche iche nke oge a (Fig. 1) 13.
Enwere ike iji electrolysis nke mmiri mepụta ike karịrị akarị nke sitere na isi mmalite mmeghari ohuru dịka anyanwụ ma ọ bụ ifufe. Enwere ike ịchekwa hydrogen emepụtara site na iji LOHC, mmiri mmiri nke hydrogenation na dehydrogenation ya nwere ike ịgbanwe agbanwe. Na usoro dehydrogenation, naanị ngwaahịa bụ hydrogen, a na-eweghachi mmiri ebuga ya na ọnọdụ mbụ ya ma mee ka hydrogen ghọọ ọzọ. Enwere ike iji hydrogen mee ihe n'ọdụ gas, batrị, ụlọ ọrụ mmepụta ihe, na ihe ndị ọzọ.
N'oge na-adịbeghị anya, a kọrọ na enwere ike ime ka ọrụ dị n'ime nke SACs ụfọdụ dịkwuo mma ma ọ bụrụ na enwere atọm ígwè dị iche iche ma ọ bụ ebe ígwè ndị ọzọ nke nanoparticles (NPs) ma ọ bụ nanoclusters (NCs) na-enye. Nke a na-emepe ohere maka nnabata na ịgbalite ihe nke substrate ahụ ọzọ, yana maka mgbanwe nke geometry na nhazi eletrọnịkị nke ebe monatomic. Ya mere, enwere ike ime ka adsorption/activation nke substrate ka mma, na-enye arụmọrụ ka mma nke catalytic n'ozuzu ya29,30. Nke a na-enye anyị echiche nke ịmepụta ihe catalytic kwesịrị ekwesị yana ebe ngwakọ na-arụ ọrụ. Ọ bụ ezie na SAC ndị ka mma egosila nnukwu ikike n'ọtụtụ ngwa catalytic, ọrụ ha na nchekwa hydrogen, dịka anyị maara, edoghị anya. N'akụkụ a, anyị na-akọ atụmatụ dị iche iche na nke siri ike maka njikọta nke cobalt-based hybrid catalists (Co-SAs/NPs@NCs) nke gụnyere nanoparticles akọwapụtara na ebe metal nke ọ bụla. Ihe ndị Co-SAs/NPs@NC kachasị mma na-egosipụta arụmọrụ dị mma nke formic acid dehydrogenation, nke ka mma karịa ihe ndị na-eme ka mmiri ghara ịdị ọcha (dịka CoNx, atọm cobalt otu, cobalt@NC na γ-Mo2N) na ọbụna ihe ndị na-eme ka mmiri ghara ịdị mma. Nkọwapụta n'ime ebe a na mgbakọ DFT nke ihe ndị na-eme ka mmiri ghara ịdị ọcha na-egosi na ebe ndị na-eme ka mmiri ghara ịdị ọcha na-arụ ọrụ dị ka ebe ndị na-eme ka mmiri ghara ịdị ọcha, na ihe ndị na-eme ka mmiri ghara ịdị ọcha nke ihe mepụtara ugbu a na-eme ka etiti d-band nke atọm Co dịkwuo mma, na-akwalite adsorption na ịgbalite HCOO*, si otú a na-ebelata ihe mgbochi ike nke mmeghachi omume ahụ.
Usoro nhazi imidazolate nke Zeolite (ZIFs) bụ ihe ndị na-ebute ụzọ atọ nke a kọwara nke ọma nke na-enye ihe mkpali maka ihe carbon dị na nitrogen (ihe na-eme ka ígwè na-akpali akpali) iji kwado ụdị ọla dị iche iche37,38. Ya mere, Co(NO3)2 na Zn(NO3)2 na-ejikọta ya na 2-methylimidazole na methanol iji mepụta ihe mgbagwoju anya ígwè ndị kwekọrọ na ngwọta. Mgbe centrifugation na nkụchara, a na-etinye CoZn-ZIF na okpomọkụ dị iche iche (750–950 °C) na ikuku nke 6% H2 na 94% Ar. Dịka egosiri na eserese dị n'okpuru, ihe ndị a na-esi na ya pụta nwere njirimara ebe dị iche iche na-arụ ọrụ ma a na-akpọ ha Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 (Foto 2a). ) . A kọwara ihe ndị a chọpụtara n'ụzọ zuru ezu banyere ụfọdụ usoro dị mkpa na usoro mmepụta ahụ na Foto 1 na 2. C1-C3. E mere ntụ ntụ okpomọkụ dị iche iche X-ray diffraction (VTXRD) iji nyochaa mgbanwe nke ihe mkpali ahụ. Mgbe okpomọkụ pyrolysis ruru 650 °C, ụkpụrụ XRD na-agbanwe nke ukwuu n'ihi ọdịda nke usoro kristal nke ZIF (Foto S4) 39. Ka okpomọkụ na-abawanye, elu abụọ sara mbara na-apụta na ụkpụrụ XRD nke Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 na 20-30 ° na 40-50 °, na-anọchite anya elu nke carbon amorphous (Foto C5). 40. Ọ dị mkpa ịmara na naanị elu atọ a na-ahụ na 44.2 °, 51.5 ° na 75.8 °, nke cobalt metal (JCPDS #15-0806), na 26.2 °, nke carbon graphitic (JCPDS # 41-1487). Usoro X-ray nke Co-SAs/NPs@NC-950 na-egosi ọnụnọ nke nanoparticles cobalt dị ka graphite na catalyst41,42,43,44. Usoro Raman na-egosi na Co-SAs/NPs@NC-950 yiri ka ọ nwere oke D na G siri ike ma dị warara karịa ihe atụ ndị ọzọ, na-egosi ọkwa dị elu nke eserese (Foto S6). Na mgbakwunye, Co-SAs/NPs@NC-950 na-egosipụta mpaghara elu Brunner-Emmett-Taylor (BET) dị elu na olu oghere (1261 m2 g-1 na 0.37 cm3 g-1) karịa ihe atụ ndị ọzọ na ọtụtụ ZIF bụ ihe ndị sitere na NC. ihe (Foto S7 na Tebụl S1). Nnyocha anya nke atom absorption spectroscopy (AAS) na-egosi na ọdịnaya cobalt nke Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@ bụ 2.69 wt%, 2.74% wt. na 2.73% wt. NC-750 n'otu n'otu (Tebụl S2). Ọdịnaya Zn nke Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 na-abawanye nwayọ nwayọ, nke a na-akọwapụta na mmụba nke mbelata na volatilization nke nkeji Zn. Mmụba na okpomọkụ pyrolysis (Zn, ebe esi mmiri = 907 °C) 45.46. Nyocha elemental (EA) gosiri na pasentị nke N na-ebelata ka okpomọkụ pyrolysis na-abawanye, oke ọdịnaya O nwere ike ịbụ n'ihi nnabata nke O2 molekul site na ikpughe na ikuku. (Tebụl S3). N'ihe dị n'ime kọbalt ụfọdụ, nanoparticles na coatoms ndị dịpụrụ adịpụ na-adị n'otu, na-ebute mmụba dị ukwuu na ọrụ mkpali, dịka a tụlere n'okpuru.
Ihe osise eserese nke njikọ nke Co-SA/NPs@NC-T, ebe T bụ okpomọkụ pyrolysis (°C). b Foto TEM. c Foto nke Co-SAs/NPs@NC-950 AC-HAADF-STEM. A na-eji okirikiri uhie akara atọm Co nke ọ bụla. d EDS Template Co-SA/NPs@NC-950.
Ihe pụrụ iche bụ na igwe onyonyo elektrọn nnyefe (TEM) gosiri na e nwere ọtụtụ nanoparticles cobalt (NPs) nke nha ha bụ 7.5 ± 1.7 nm naanị na Co-SA/NPs@NC-950 (Foto 2 b na S8). A na-eji carbon dị ka graphite kpuchie nanoparticles ndị a. Oghere dị n'etiti 0.361 na 0.201 nm kwekọrọ na ihe ndị dị n'ime carbon graphitic (002) na metallic Co (111), n'otu n'otu. Na mgbakwunye, igwe onyonyo elektrọn mgbasa ozi annular nke aberration-corrected annular dark-field scanning transmission (AC-HAADF-STEM) kpughere na Co NPs dị na Co-SAs/NPs@NC-950 gbara ya gburugburu site na ọtụtụ cobalt atom (Foto 2c). Agbanyeghị, naanị atọm cobalt gbasaara n'ime atom ka a hụrụ na nkwado nke ihe atụ abụọ ndị ọzọ (Foto S9). Foto HAADF-STEM nke na-egosi nkesa otu otu nke C, N, Co na Co NPs nkewapụrụ na Co-SAs/NPs@NC-950 (Foto 2d). Nsonaazụ ndị a niile na-egosi na e jikọtara ebe Co nkewapụrụ na ihe ndị dị ka carbon graphite nke a na-etinye n'ime N-doped na substrates NC na Co-SAs/NPs@NC-950 nke ọma, ebe naanị ebe metal dị iche.
E jiri X-ray photoelectron spectroscopy (XPS) mụọ ọnọdụ valence na nhazi kemịkalụ nke ihe ndị e nwetara. Spektra XPS nke ihe mkpali atọ ahụ gosiri ọnụnọ nke ihe Co, N, C na O, mana Zn dị naanị na Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 (Foto 2).). C10). Ka okpomọkụ pyrolysis na-abawanye, ọdịnaya nitrogen zuru oke na-ebelata ka ụdị nitrogen na-aghọ ihe na-adịghị akwụsi ike ma na-agbaze ghọọ gas NH3 na NOx na okpomọkụ dị elu (Tebụl S4) 47. Ya mere, mkpokọta ọdịnaya carbon ji nwayọọ nwayọọ mụbaa site na Co-SAs/NPs@NC-750 gaa na Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-950 (Foto S11 na S12). Ihe nlele pyrolyzed na okpomọkụ dị elu nwere obere akụkụ nke atọm nitrogen, nke pụtara na ọnụọgụ nke ndị na-ebu NC na Co-SAs/NPs@NC-950 kwesịrị ịdị obere karịa nke na ihe nlele ndị ọzọ. Nke a na-eduga n'ịme ka ihe ndị na-adịghị na kobalt sie ike. Ọkwa O1s na-egosi elu abụọ C=O (531.6 eV) na C–O (533.5 eV), n'otu n'otu (Foto S13) 48. Dịka egosiri na Foto 2a, enwere ike idozi spectrum N1s n'ime oke anọ nke pyridine nitrogen N (398.4 eV), pyrrole N (401.1 eV), graphite N (402.3 eV) na Co-N (399.2 eV). Njikọ Co-N dị na ihe atụ atọ niile, na-egosi na ụfọdụ atọm N na-ejikọta na ebe monometallic, mana njirimara dị iche iche nke ukwuu49. Itinye okpomọkụ pyrolysis dị elu nwere ike ibelata ọdịnaya nke ụdị Co-N nke ukwuu site na 43.7% na Co-SA/NPs@NC-750 ruo 27.0% na Co-SAs/NPs@NC-850 na Co 17.6%@ NC-950. na -CA/NPs, nke kwekọrọ na mmụba nke ọdịnaya C (Foto 3a), na-egosi na ọnụọgụ nhazi Co-N ha nwere ike ịgbanwe ma jiri atọm C50 dochie ya. Ụdị Zn 2p na-egosi na ihe a dịkarịsịrị n'ụdị Zn2+. (Foto S14) 51. Ụdị Co 2p na-egosi oke elu abụọ a ma ama na 780.8 na 796.1 eV, nke a na-akpọ Co 2p3/2 na Co 2p1/2, n'otu n'otu (Foto 3b). Ma e jiri ya tụnyere Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750, a na-agbanwe oke Co-N na Co-SAs/NPs@NC-950 gaa n'akụkụ dị mma, na-egosi na otu atọm Co na elu -SAs/NPs@NC-950 nwere oke mbelata elektrọn dị elu, na-ebute ọnọdụ oxidation dị elu. Ọ dị mkpa ịmara na naanị Co-SAs/NPs@NC-950 gosiri oke adịghị ike nke cobalt efu-valent (Co0) na 778.5 eV, nke na-egosi na enwere nanoparticles sitere na nchịkọta nke cobalt SA na oke okpomọkụ dị elu.
a N 1s na b Co 2p spectra nke Co-SA/NPs@NC-T. c XANES na d FT-EXAFS spectra nke Co-K-edge nke Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750. e WT-EXAFS contour plans nke Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850, na Co-SAs/NPs@NC-750. f FT-EXAFS set curve maka Co-SA/NPs@NC-950.
E jiri X-ray absorption spectroscopy (XAS) nke ejiri oge mechie iji nyochaa nhazi eletrọniki na gburugburu nhazi nke ụdị Co dị na ihe nlele akwadoro. Ọnọdụ Cobalt valence na Co-SAs/NPs@NC-950, Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 Edge nke ekpughere site na nnabata X-ray dị nso-ubi nke Co-K edge (XANES) spectrum. Dịka egosiri na Foto 3c, nnabata dị nso na nsọtụ nke ihe atụ atọ ahụ dị n'etiti foils Co na CoO, na-egosi na ọnọdụ valence nke ụdị Co dị site na 0 ruo +253. Na mgbakwunye, a hụrụ mgbanwe gaa na ike dị ala site na Co-SAs/NPs@NC-950 gaa na Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750, na-egosi na Co-SAs/NPs@NC-750 nwere ọnọdụ oxidation dị ala. usoro ntụgharị. Dịka nsonaazụ njikọta ahịrị si dị, a na-eme atụmatụ na ọnọdụ Co-SAs/NPs@NC-950 bụ +0.642, nke dị ala karịa ọnọdụ Co-SAs/NPs@NC-850 (+1.376). Co-SA/NP @NC-750 (+1.402). Nsonaazụ ndị a na-egosi na nkezi ọnọdụ oxidation nke ihe ndị dị na Co-SAs/NPs@NC-950 belatara nke ukwuu, nke kwekọrọ na nsonaazụ XRD na HADF-STEM ma enwere ike ịkọwa ya site na ịdị n'otu nke nanoparticles cobalt na otu cobalt. . Atọm Co 41. Ụdị nhazi ihe eji eme ka ihe dị nro nke Fourier transform X-ray absorption fine structure (FT-EXAFS) nke Co K-edge na-egosi na isi elu dị na 1.32 Å bụ nke Co-N/Co-C shei, ebe ụzọ mgbasa nke Co-Co metallic dị na 2.18 naanị na Co-SAs Å nke achọtara na /NPs@NC-950 (Foto 3d). Ọzọkwa, eserese nhazi wavelet transform (WT) na-egosi ike kachasị na 6.7 Å-1 nke Co-N/Co-C nyere, ebe naanị Co-SAs/NPs@NC-950 na-egosi ike kachasị nke 8.8 nyere. Ike ọzọ kachasị dị na Å−1 na njikọ Co-Co (Foto 3e). Na mgbakwunye, nyocha EXAFS nke onye nwe ụlọ mere gosiri na na okpomọkụ pyrolysis nke 750, 850 na 950 °C, ọnụọgụ nhazi Co-N bụ 3.8, 3.2 na 2.3, n'otu n'otu, ọnụọgụ nhazi Co-C bụ 0. 0.9 na 1.8 (Foto 3f, S15 na Tebụl S1). N'ụzọ pụrụ iche, enwere ike ịkọwa nsonaazụ kachasị ọhụrụ na ọnụnọ nke nkeji CoN2C2 na nanoparticles gbasaara na Co-SAs/NPs@NC-950. N'ụzọ dị iche, na Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750, naanị nkeji CoN3C na CoN4 dị. O doro anya na ka okpomọkụ pyrolysis na-abawanye, a na-eji atọm C dochie atọm N na nkeji CoN4, na ngwakọta cobalt CA iji mepụta nanoparticles.
E jiri ọnọdụ mmeghachi omume nke a mụrụ na mbụ mụọ mmetụta nke ọnọdụ nkwadebe na njirimara nke ihe dị iche iche (Foto S16)17,49. Dịka egosiri na Foto 4 a, ọrụ nke Co-SAs/NPs@NC-950 dị elu nke ukwuu karịa nke Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750. Ihe pụrụ iche bụ na ihe nlele Co atọ niile a kwadebere gosipụtara arụmọrụ ka mma ma e jiri ya tụnyere ihe ndị na-eme ka ígwè dị oké ọnụ ahịa dị na azụmahịa (Pd/C na Pt/C). Na mgbakwunye, ihe nlele Zn-ZIF-8 na Zn-NC anaghị arụ ọrụ na formic acid dehydrogenation, na-egosi na ihe ndị dị na Zn abụghị ebe na-arụ ọrụ, mana mmetụta ha na ọrụ ahụ enweghị atụ. Na mgbakwunye, ọrụ nke Co-SAs/NPs@NC-850 na Co-SAs/NPs@NC-750 nwetara pyrolysis nke abụọ na 950°C maka otu awa, mana ọ dị ala karịa nke Co-SAs/NPs@NC-750. @NC-950 (Foto S17). Nhazi nke ihe ndị a gosiri na e nwere Co nanoparticles na ihe nlele ndị a na-emegharị emegharị, mana obere ala na enweghị carbon dị ka graphite mere ka ọrụ dị ala ma e jiri ya tụnyere Co-SAs/NPs@NC-950 (Foto S18–S20). A tụnyerekwara ọrụ nke ihe nlele nwere ọnụọgụ dị iche iche nke Co precursor, yana ọrụ kachasị elu egosiri na mgbakwunye 3.5 mol (Tebụl S6 na Foto S21). O doro anya na mmepụta nke ebe dị iche iche nke ígwè na-emetụta site na ọdịnaya hydrogen na ikuku pyrolysis na oge pyrolysis. Ya mere, a tụlere ihe Co-SAs/NPs@NC-950 ndị ọzọ maka ọrụ formic acid dehydrogenation. Ihe niile gosiri arụmọrụ dị mma ruo nke ọma; agbanyeghị, ọ dịghị nke ka Co-SAs/NPs@NC-950 mma (Foto S22 na S23). Njimara nhazi nke ihe ahụ gosiri na ka oge pyrolysis na-abawanye, ọdịnaya nke ọnọdụ monoatomic Co-N na-ebelata nwayọ nwayọ n'ihi nchịkọta nke atọm ígwè n'ime nanoparticles, nke na-akọwa ọdịiche dị n'ọrụ dị n'etiti ihe nlele nwere oge pyrolysis nke 100-2000. ọdịiche. 0.5 awa, 1 awa, na 2 awa (Foto S24–S28 na Tebụl S7).
Eserese nke olu gas na oge e nwetara n'oge mwepụ nke ngwakọta mmanụ ọkụ site na iji ihe mkpali dị iche iche. Ọnọdụ mmeghachi omume: FA (10 mmol, 377 μl), ihe mkpali (30 mg), PC (6 ml), ihe mgbaze: 110 °C, Usoro: 98 °C, akụkụ anọ b Co-SAs/NPs@NC-950 (30 mg), ihe mgbaze dị iche iche. c Ntụnyere ọnụego evolushọn gas nke ihe mgbaze dị iche iche na ihe mgbaze organic na 85–110 °C. d Nnyocha imegharị Co-SA/NPs@NC-950. Ọnọdụ mmeghachi omume: FA (10 mmol, 377 µl), Co-SAs/NPs@NC-950 (30 mg), ihe mgbaze (6 ml), Tback: 110 °C, Usoro: 98 °C, okirikiri mmeghachi omume ọ bụla na-ewe otu awa. Ogwe njehie na-anọchite anya ọdịiche ọkọlọtọ agbakọrọ site na ule atọ na-arụ ọrụ.
N'ozuzu, arụmọrụ nke ihe na-akpali mmepụta mmiri mmiri nke FA dabere nke ukwuu na ọnọdụ mmeghachi omume, ọkachasị ihe na-agbaze mmiri ejiri mee ihe8,49. Mgbe ejiri mmiri mee ihe dị ka ihe mgbaze, Co-SAs/NPs@NC-950 gosiri ọnụego mmeghachi omume mbụ kachasị elu, mana mwepụ ọrụ mere, ikekwe n'ihi protons ma ọ bụ H2O18 bi na ebe ndị na-arụ ọrụ. Nnwale nke ihe na-akpali mmepụta mmiri na ihe mgbaze organic dị ka 1,4-dioxane (DXA), n-butyl acetate (BAC), toluene (PhMe), triglyme na cyclohexanone (CYC) egosighikwa ọganihu ọ bụla, na na propylene carbonate (PC) ) (Fig. 4b na Tebụl S8). N'otu aka ahụ, ihe mgbakwunye dị ka triethylamine (NET3) ma ọ bụ sodium formate (HCCONa) enweghị mmetụta dị mma ọzọ na arụmọrụ ihe na-akpali mmepụta mmiri (Foto S29). N'okpuru ọnọdụ mmeghachi omume kacha mma, mmịpụta gas ruru 1403.8 mL g−1 h−1 (Foto S30), nke dị elu karịa ihe niile e kwuru na mbụ na Co catalyst (gụnyere SAC17, 23, 24). N'ọtụtụ nnwale, ewezuga mmeghachi omume na mmiri na ihe mgbakwunye formate, enwetara nhọrọ ruo 99.96% maka dehydrogenation na dehydration (Tebụl S9). Ike mkpali agbakọrọ bụ 88.4 kJ/mol, nke yiri ike mkpali nke ihe na-akpali akpali ọla dị mma (Foto S31 na Tebụl S10).
Na mgbakwunye, anyị tụnyere ọtụtụ ihe ndị ọzọ na-akpali akpali maka mwepu acid formic n'okpuru ọnọdụ ndị yiri ya (Foto 4c, tebụl S11 na S12). Dịka egosiri na Foto 3c, ọnụego mmepụta gas nke Co-SAs/NPs@NC-950 karịrị nke ihe ndị a maara dịka ihe na-akpali akpali ígwè dị iche iche ma dị elu karịa nke 5% Pd/C na 5% Pd/C, n'otu n'otu. otu ugboro. % Pt/C ihe na-akpali akpali.
Otu ihe dị mkpa n'iji ihe ọ bụla bara uru nke ihe na-akpali mmeghachi omume (de) hydrogenation bụ nkwụsi ike ha. Ya mere, e mere usoro nnwale imegharị ihe site na iji Co-SAs/NPs@NC-950. Dịka egosiri na Foto 4 d, ọrụ mbụ na nhọrọ nke ihe ahụ ka na-agbanweghi agbanwe n'ime ọsọ ise na-esochi anya (lee Tebụl S13 kwa). E mere ule ogologo oge ma mmepụta gas mụbara n'usoro n'ime awa 72 (Foto S32). Ọdịnaya cobalt nke Co-SA/NPs@NC-950 ejiri mee ihe bụ 2.5 wt%, nke dị nnọọ nso na nke ihe na-akpali mmeghachi omume ọhụrụ, na-egosi na enweghị ntụpọ doro anya nke cobalt (Tebụl S14). A hụghị mgbanwe agba ma ọ bụ nchịkọta nke ihe ígwè doro anya tupu na mgbe mmeghachi omume gasịrị (Foto S33). AC-HAADF-STEM na EDS nke ihe ndị e tinyere na nnwale ogologo oge gosiri njigide na mgbasa otu nke ebe mgbasa ozi atom na enweghị mgbanwe nhazi dị mkpa (Foto S34 na S35). Ọnụ ọgụgụ kachasị elu nke Co0 na Co-N ka dị na XPS, na-egosi ịdị n'otu nke Co NPs na ebe metal nke ọ bụla, nke na-akwadokwa nkwụsi ike nke Co-SAs/NPs@NC-950 catalyst (Foto S36).
Iji chọpụta ebe kachasị arụ ọrụ na-akpata mwepu acid formic, e mere ihe ndị a họọrọ nwere naanị otu etiti ígwè (CoN2C2) ma ọ bụ Co NP dabere na ọmụmụ ihe ndị gara aga17. Usoro nke ọrụ mwepu acid formic acid hụrụ n'okpuru otu ọnọdụ ahụ bụ Co-SAs/NPs@NC-950 > Co SA > Co NP (Tebụl S15), na-egosi na ebe CoN2C2 gbasaara n'ime atọm na-arụ ọrụ karịa NPs. Mmegharị mmeghachi omume na-egosi na evolushọn hydrogen na-eso usoro mmeghachi omume mbụ, mana mkpọda nke ọtụtụ akụkụ dị iche iche na ọdịnaya cobalt dị iche iche abụghị otu, na-egosi na kinetics dabere na ọ bụghị naanị na formic acid, kamakwa na saịtị na-arụ ọrụ (Fig. 2). C37). Ọmụmụ kinetic ndị ọzọ gosiri na, ebe enweghị oke ọla kọbalt na nyocha diffraction X-ray, a chọpụtara na usoro kinetic nke mmeghachi omume n'ihe gbasara ọdịnaya cobalt bụ 1.02 na ọkwa dị ala (erughị 2.5%), na-egosi nkesa fọrọ nke nta ka ọ bụrụ otu nke ebe cobalt monoatomic. isi. ebe ọrụ (fig. S38 na S39). Mgbe ọdịnaya nke ihe ndị dị na Co ruru 2.7%, r na-abawanye na mberede, na-egosi na ihe ndị dị na nanoparticles na-emekọrịta nke ọma na atọm nke ọ bụla iji nweta ọrụ dị elu. Ka ọdịnaya nke ihe ndị dị na Co na-abawanye, usoro ahụ na-aghọ nke na-abụghị ahịrị, nke jikọtara ya na mmụba na ọnụọgụ nke ihe ndị dị na nanoparticles na mbelata na ọnọdụ monatomic. Ya mere, arụmọrụ LC dehydrogenation ka mma nke Co-SA/NPs@NC-950 na-esite na omume mmekorita nke ebe metal nke ọ bụla na ihe ndị dị na nanoparticles.
E mere nnyocha miri emi site na iji in situ diffuse reflectance Fourier transform (in situ DRIFT) iji chọpụta ihe ndị na-eme ka mmeghachi omume dị n'ime usoro ahụ. Mgbe a kpochara ihe nlele ahụ na okpomọkụ mmeghachi omume dị iche iche mgbe etinyere formic acid, a hụrụ usoro ugboro abụọ (Fig. 5a). Ọnụ ọgụgụ atọ nke HCOOH* pụtara na 1089, 1217 na 1790 cm-1, nke a na-akọwapụta na mkpọtụ CH π (CH) na-apụta n'èzí, mkpọtụ CO ν (CO) na mkpọtụ agbatị C=O ν (C=O) na mkpọtụ agbatị C=O ν (C=O), 54, 55 n'otu n'otu. Otu elu ọzọ dị na 1363 na 1592 cm-1 kwekọrọ na mkpọtụ OCO symmetric νs(OCO) na mkpọtụ agbatị OCO νas(OCO)33.56 HCOO*, n'otu n'otu. Ka mmeghachi omume ahụ na-aga n'ihu, ọnụ ọgụgụ ndị dị na HCOOH* na HCOO* na-ebelata nwayọ. N'ozuzu, mmebi nke formic acid gụnyere usoro atọ dị mkpa: (I) ịmịnye formic acid n'ebe ndị na-arụ ọrụ, (II) iwepụ H site na ụzọ formate ma ọ bụ carboxylate, na (III) njikọta nke H abụọ a na-etinye n'ime mmiri iji mepụta hydrogen. HCOO* na COOH* bụ isi ihe dị mkpa n'ịchọpụta ụzọ formate ma ọ bụ carboxylate, n'otu n'otu57. Na sistemụ catalytic anyị, naanị oke HCOO* a na-ahụkarị pụtara, na-egosi na mmebi nke formic acid na-eme naanị site na ụzọ formic acid58. E mere ihe ndị yiri ya na obere okpomọkụ nke 78 °C na 88 °C (fig. S40).
In situ DRIFT spectra nke HCOOH dehydrogenation na Co-SAs/NPs@NC-950 na b Co SAs. Akụkọ ahụ na-egosi oge mmeghachi omume n'ebe ahụ. c Mgbanwe nke olu gas enwetara site na iji ihe ndị na-eme ka isotope labeling dị iche iche. d Data mmetụta isotope Kinetic.
E mere nnwale DRIFT yiri nke ahụ na ihe ndị metụtara ya Co NP na Co SA iji mụọ mmetụta synergistic na Co-SA/NPs@NC-950 (Foto 5 b na S41). Ihe abụọ a na-egosi usoro yiri nke ahụ, mana elu njirimara nke HCOOH* na HCOO* agbanweela ntakịrị, na-egosi na ntinye nke Co NPs na-agbanwe nhazi eletrọniki nke etiti monoatomic. Oke njirimara νas(OCO) na-apụta na Co-SAs/NPs@NC-950 na Co SA mana ọ bụghị na Co NPs, na-egosikwa na etiti e guzobere mgbe etinyere formic acid bụ monodentate formic acid perpendicular na elu nnu plane. a na-etinyekwa ya na SA dị ka ebe na-arụ ọrụ 59. Ọ dị mkpa ịmara na a hụrụ mmụba dị ukwuu na mkpọtụ nke elu njirimara π(CH) na ν(C = O), nke yiri ka ọ butere mgbagọ nke HCOOH* ma mee ka mmeghachi omume ahụ dị mfe. N'ihi ya, oke njirimara nke HCOOH* na HCOO* na Co-SAs/NPs@NC fọrọ nke nta ka ọ pụọ ​​mgbe nkeji 2 nke mmeghachi omume gasịrị, nke dị ngwa karịa nke monometallic (nkeji 6) na nanoparticle-based catalysts (nkeji 12). Nsonaazụ ndị a niile na-akwado na nanoparticle doping na-eme ka adsorption na ọrụ nke intermediates dịkwuo mma, si otú a na-eme ka mmeghachi omume ndị a tụrụ aro n'elu dịkwuo ngwa ngwa.
Iji nyochaa ụzọ mmeghachi omume ma chọpụta usoro ikpebi ọnụego (RDS), e mere mmetụta KIE n'ihu Co-SAs/NPs@NC-950. N'ebe a, a na-eji isotopes formic acid dị iche iche dị ka HCOOH, HCOOD, DCOOH na DCOOD maka ọmụmụ ihe KIE. Dịka egosiri na Foto 5c, ọnụego dehydrogenation na-ebelata n'usoro ndị a: HCOOH > HCOOD > DCOOH > DCOOD. Na mgbakwunye, uru agbakọrọ nke KHCOOH/KHCOOD, KHCOOH/KDCOOH, KHCOOD/KDCOOD na KDCOOH/KDCOOD bụ 1.14, 1.71, 2.16 na 1.44, n'otu n'otu (Foto 5d). Ya mere, nkewa njikọ CH na HCOO* na-egosi ụkpụrụ kH/kD>>1.5, na-egosi nnukwu mmetụta kinetic60,61, ma yie ka ọ na-anọchite anya RDS nke HCOOH dehydrogenation na Co-SAs/NPs@NC-950.
Tinyere nke ahụ, e mere ngụkọ DFT iji ghọta mmetụta nke nanoparticles doped nwere na ọrụ dị n'ime Co-SA. E wuru ụdị Co-SAs/NPs@NC na Co-SA dabere na nnwale egosiri na ọrụ ndị gara aga (Fig. 6a na S42)52,62. Mgbe emechara nhazi geometric, achọpụtara obere nanoparticles Co6 (CoN2C2) ndị na-ebikọ na unit monoatomic, a chọpụtakwara ogologo njikọ Co-C na Co-N na Co-SA/NPs@NC ka ọ bụrụ 1.87 Å na 1.90 Å, n'otu n'otu. , nke kwekọrọ na nsonaazụ XAFS. Njupụta akụkụ nke steeti agbakọrọ (PDOS) na-egosi na atọm Co metal na nanoparticle composite (Co-SAs/NPs@NC) na-egosipụta njikọta dị elu nso ọkwa Fermi ma e jiri ya tụnyere CoN2C2, nke na-ebute HCOOH. Nnyefe elektrọn gbawara agbawa na-arụ ọrụ nke ọma karịa (Foto 6b na S43). E gbakọrọ ebe d-band nke Co-SAs/NPs@NC na Co-SA ka ha bụrụ -0.67 eV na -0.80 eV, n'otu n'otu, nke gụnyere mmụba nke Co-SAs/NPs@NC bụ 0.13 eV, nke mere ka o kwe omume na mgbe ewebatara NP, ntinye nke ihe ndị dị na HCOO* site na nhazi eletrọnịkị agbanwere nke CoN2C2 na-eme. Ọdịiche dị na njupụta chajị na-egosi nnukwu igwe ojii eletrọn gburugburu ngọngọ CoN2C2 na nanoparticle, na-egosi mmekọrịta siri ike n'etiti ha n'ihi mgbanwe eletrọn. Ejikọtara ya na nyocha chajị Bader, achọpụtara na Co nke a gbasasịrị n'ime atomic tụfuru 1.064e na Co-SA/NPs@NC na 0.796e na Co SA (Foto S44). Nsonaazụ ndị a na-egosi na njikọta nke nanoparticles na-eduga na mbelata eletrọn nke saịtị Co, na-ebute mmụba na Covalence, nke kwekọrọ na nsonaazụ XPS (Foto 6c). A tụlere njirimara mmekọrịta Co-O nke HCOO adsorption na Co-SAs/NPs@NC na Co SA site na ịgbakọ otu Hamiltonian orbital crystalline (COHP)63. Dịka egosiri na Foto 6 d, ụkpụrụ ọjọọ na nke dị mma nke -COHP kwekọrọ na ọnọdụ mgbochi njikọ na ọnọdụ njikọ, n'otu n'otu. A tụlere ike njikọ nke Co-O nke HCOO (Co-carbonylO HCOO*) nabatara site na ijikọta ụkpụrụ -COHP, nke bụ 3.51 na 3.38 maka Co-SAs/NPs@NC na Co-SA, n'otu n'otu. HCOOH adsorption gosikwara nsonaazụ ndị yiri ya: mmụba na uru dị mkpa nke -COHP mgbe doping nanoparticle gosiri mmụba na njikọ Co-O, si otú a na-akwalite mkpali nke HCOO na HCOOH (Foto S45).
Nhazi lattice nke Co-SA/NPs@NC-950. b PDOS Co-SA/NP@NC-950 na Co SA. c 3D isosurface nke ọdịiche dị na njupụta chajị nke HCOOH adsorption na Co-SA/NPs@NC-950 na Co-SA. (d) pCOHP nke Co-O agbụ nke HCOO na-etinye na Co-SA/NPs@NC-950 (aka ekpe) na Co-SA (aka nri). e Ụzọ mmeghachi omume nke HCOOH dehydrogenation na Co-SA/NPs@NC-950 na Co-SA.
Iji ghọta nke ọma arụmọrụ dehydrogenation dị elu nke Co-SA/NPs@NC, e guzobere ụzọ na ike mmeghachi omume. N'ụzọ pụrụ iche, dehydrogenation FA gụnyere usoro ise, gụnyere ntụgharị nke HCOOH ka ọ bụrụ HCOOH*, HCOOH* ka ọ bụrụ HCOO* + H*, HCOO* + H* ka ọ bụrụ 2H* + CO2*, 2H* + CO2* ka ọ bụrụ 2H* + CO2, na 2H* na H2 (Foto 6e). Ike adsorption nke molekul formic acid dị n'elu catalyst site na carboxylic oxygen dị ala karịa site na hydroxyl oxygen (Foto S46 na S47). Mgbe nke ahụ gasịrị, n'ihi ike dị ala, adsorbate na-eme nkewa njikọ OH iji mepụta HCOO* kama nkewa njikọ CH iji mepụta COOH*. N'otu oge ahụ, HCOO* na-eji monodentate adsorption, nke na-akwalite mmebi nke njikọ na nhazi nke CO2 na H2. Nsonaazụ ndị a kwekọrọ na ọnụnọ nke νas(OCO) elu na in situ DRIFT, na-egosikwa na mmebi FA na-eme site na ụzọ nhazi na ọmụmụ ihe anyị. Ọ dị mkpa ịmara na dịka nha KIE si dị, nkewa CH nwere ihe mgbochi ike mmeghachi omume dị elu karịa usoro mmeghachi omume ndị ọzọ ma na-anọchite anya RDS. Ihe mgbochi ike nke sistemụ Co-SAs/NPs@NC kacha mma bụ 0.86 eV dị ala karịa nke Co-SA (1.2 eV), nke na-eme ka arụmọrụ dehydrogenation zuru oke ka mma. Ihe pụrụ iche bụ na ọnụnọ nke nanoparticles na-achịkwa usoro eletrọnịkị nke ebe coactive gbasaara n'ime atomic, nke na-eme ka adsorption na mkpali nke ndị etiti dịkwuo mma, si otú a na-ebelata ihe mgbochi mmeghachi omume ma na-akwalite mmepụta hydrogen.
Na nchịkọta, anyị na-egosi maka oge mbụ na arụmọrụ catalytic nke ihe na-akpali mmepụta hydrogen nwere ike imeziwanye nke ọma site na iji ihe ndị nwere ebe monometallic kesara nke ukwuu na obere nanoparticles. Echiche a egosipụtala site na njikọta nke ihe na-akpali ígwè otu atọm nke cobalt nke ejiri nanoparticles gbanwee (Co-SAs/NPs@NC), yana ihe ndị metụtara ya nwere naanị ebe otu metal (CoN2C2) ma ọ bụ Co NPs. E ji usoro pyrolysis dị mfe otu nzọụkwụ kwadebe ihe niile. Nyocha nhazi na-egosi na ihe na-akpali akpali kacha mma (Co-SAs/NPs@NC-950) nwere nkeji CoN2C2 nke a na-agbasasị na obere nanoparticles (7-8 nm) nke ejiri nitrogen na graphite dị ka carbon mee. O nwere mmepụta gas dị mma ruo 1403.8 ml g-1 h-1 (H2:CO2 = 1.01:1), nhọrọ H2 na CO nke 99.96% ma nwee ike ịnọgide na-arụ ọrụ mgbe niile ruo ọtụtụ ụbọchị. Ọrụ nke ihe mkpali a karịrị ọrụ nke ụfọdụ ihe mkpali Co SA na Pd/C site na ugboro 4 na 15, n'otu n'otu. Nnwale DRIFT dị na ya na-egosi na ma e jiri ya tụnyere Co-SA, Co-SAs/NPs@NC-950 na-egosipụta ike siri ike nke monodentate adsorption nke HCOO*, nke dị mkpa maka ụzọ nhazi, na nanoparticles dopant nwere ike ịkwalite mkpali HCOO* na ọsọ C-H. Achọpụtara nkewa njikọ dị ka RDS. Ngụkọta echiche na-egosi na Co NP doping na-eme ka etiti d-band nke atọm Co otu site na 0.13 eV site na mmekọrịta, na-eme ka adsorption nke HCOOH* na HCOO* dị elu, si otú a na-ebelata ihe mgbochi mmeghachi omume site na 1.20 eV maka Co SA ruo 0 .86 eV. Ọ bụ ya na-ahụ maka arụmọrụ pụrụ iche.
N'ụzọ sara mbara karị, nnyocha a na-enye echiche maka imepụta ihe ọhụrụ na-akpali ígwè atọm ma na-eme ka nghọta dịkwuo mma banyere otu esi eme ka arụmọrụ katalytic ka mma site na mmetụta synergistic nke ebe ígwè dị iche iche nha. Anyị kwenyere na usoro a nwere ike ịgbatị n'ọtụtụ sistemụ katalytic ndị ọzọ ngwa ngwa.
A zụtara Co(NO3)2 6H2O (AR, 99%), Zn(NO3)2 6H2O (AR, 99%), 2-methylimidazole (98%), methanol (99.5%), propylene carbonate (PC, 99%) ethanol (AR, 99.7%) na McLean, China. A zụtara Formic acid (HCOOH, 98%) na Rhawn, China. A na-eji ihe ndị na-emepụta ihe niile ozugbo na-enweghị nhicha ọzọ, a na-ejikwa usoro nhicha ultrapure kwadebe mmiri ultrapure. A zụtara Pt/C (ibu ibu 5%) na Pd/C (ibu ibu 5%) na Sigma-Aldrich.
Emere nhazi nke nanocrystals CoZn-ZIF dabere na usoro ndị gara aga yana ụfọdụ mgbanwe23,64. Nke mbụ, agwakọtara 30 mmol Zn(NO3)2·6H2O (8.925 g) na 3.5 mmol Co(NO3)2·6H2O (1.014 g) ma gbazee na 300 ml nke methanol. Mgbe ahụ, a gbazere 120 mmol nke 2-methylimidazole (9.853 g) na 100 ml nke methanol ma tinye ya na ngwọta dị n'elu. A kpalitere ngwakọta ahụ na okpomọkụ ụlọ ruo awa 24. N'ikpeazụ, e kewara ngwaahịa ahụ site na centrifugation na 6429 g maka nkeji 10 ma saa ya nke ọma na methanol ugboro atọ. A kpọrọ ntụ ntụ ahụ na-esi na vacuum na 60°C n'abalị tupu ejiri ya.
Iji mepụta Co-SAs/NPs@NC-950, a na-etinye ntụ ntụ CoZn-ZIF kpọrọ nkụ na 950 °C ruo otu awa n'ime mmiri gas nke 6% H2 + 94% Ar, yana ọnụego ọkụ nke 5 °C/min. E mesịa, a jụrụ ihe nlele ahụ ka ọ dị jụụ ruo na okpomọkụ ụlọ iji nweta Co-SA/NPs@NC-950. Maka Co-SAs/NPs@NC-850 ma ọ bụ Co-SAs/NPs@NC-750, a gbanwere okpomọkụ pyrolysis gaa na 850 na 750 °C, n'otu n'otu. Enwere ike iji ihe nlele ndị a kwadebere na-enweghị nhazi ọzọ, dị ka ịcha acid.
E mere nha TEM (nkịtị elektrọn nnyefe) na igwe onyonyo Thermo Fisher Titan Themis 60-300 "cube" nke nwere ihe na-edozi ihe maka onyonyo na lensị na-akpụ ihe nyocha 300 kV. E mere nnwale HAADF-STEM site na iji igwe onyonyo FEI Titan G2 na FEI Titan Themis Z nke nwere ihe nyocha na ihe na-edozi onyonyo, yana ihe nchọpụta nkebi anọ nke DF4. E nwetakwara onyonyo maapụ elemental EDS na igwe onyonyo FEI Titan Themis Z. E mere nyocha XPS na igwe onyonyo fotoelectron X-ray (ihe nlereanya Thermo Fisher ESCALAB 250Xi). E jiri tebụl XAFS-500 (China Spectral Instruments Co., Ltd.) chịkọta XANES na spectra EXAFS nke Co K-edge. E jiri atom absorption spectroscopy (AAS) (PinAAcle900T) chọpụta ọdịnaya Co. E dekọrọ spectra X-ray diffractometer (XRD) na X-ray diffractometer (Bruker, Bruker D8 Advance, Germany). E ji ngwa a na-akpọ physical adsorption (Micromeritics, ASAP2020, USA) nweta ihe ndị na-eme ka nitrogen adsorption dị n'ọbara.
E mere mmeghachi omume dehydrogenation n'ime ikuku argon wee wepụ ikuku dịka usoro Schlenk ọkọlọtọ si dị. E wepụrụ arịa mmeghachi omume ahụ ma tinye argon ugboro isii. Gbanye mmiri condenser ahụ ma tinye ihe na-eme ka ihe na-agbaze (30 mg) na ihe mgbaze (6 ml). Kpoo akpa ahụ ruo okpomọkụ achọrọ site na iji thermostat ma kwe ka ọ nhata ruo nkeji iri atọ. E tinyeziri Formic acid (10 mmol, 377 μL) na arịa mmeghachi omume n'okpuru argon. Tụgharịa valvụ burette ụzọ atọ iji belata nrụgide nke reactor ahụ, mechie ya ọzọ, wee malite ịtụ olu gas emepụtara site na iji burette aka (Foto S16). Mgbe oge achọrọ ka mmeghachi omume ahụ mechaa, a chịkọtara ihe nlele gas maka nyocha GC site na iji sirinji gas nke ejiri argon sachaa.
E mere nnwale Insitu drift na Fourier transform infrared (FTIR) spectrometer (Thermo Fisher Scientific, Nicolet iS50) nke nwere ihe nchọpụta mercury cadmium telluride (MCT). E tinyere ntụ ntụ catalyst ahụ na sel reaction (Harrick Scientific Products, Praying Mantis). Mgbe e jiri iyi Ar (50 ml/min) gwọọ catalyst ahụ na okpomọkụ ụlọ, a na-ekpo ọkụ ihe nlele ahụ ruo na okpomọkụ enyere, wee jiri Ar (50 ml/min) fụpụ ya na ngwọta HCOOH wee wụsa ya na sel reaction in-situ. maka mmeghachi omume. Usoro catalytic dị iche iche. E dekọrọ spectra infrared n'oge dị iche iche site na sekọnd 3.0 ruo 1 awa.
A na-eji HCOOH, DCOOH, HCOOD na DCOOD eme ihe dị ka ihe ndị na-eme ka mmiri dị n'ime propylene carbonate. Ọnọdụ ndị ọzọ kwekọrọ na usoro mwepụ mmiri HCOOH.
E jiri usoro ozizi ọrụ njupụta mee ngụkọ mbụ n'ime ngwugwu ihe nlereanya Vienna Ab initio (VASP 5.4.4) 65,66. E jiri mkpụrụ ndụ superunit nwere elu graphene (5 × 5) nwere akụkụ transverse nke ihe dị ka 12.5 Å dị ka ihe ndabere maka CoN2C2 na CoN2C2-Co6. E tinyere anya oghere karịrị 15 Å iji zere mmekọrịta n'etiti oyi akwa substrate dị nso. A kọwara mmekọrịta dị n'etiti ions na electrons site na usoro ebili mmiri amplified (PAW) nke a na-atụ anya ya65,67. E jiri ọrụ Perdue-Burke-Ernzerhoff (PBE) generalized gradient approximation (GGA) nke Grimm tụrụ aro ya na van der Waals correction68,69. Usoro njikọta maka ike na ike zuru oke bụ 10−6 eV/atom na 0.01 eV/Å. E tinyere mbepụ ike na 600 eV site na iji grid isi Monkhorst-Pack 2 × 2 × 1 K. A na-eji nhazi eletrọnịkị arụ ọrụ na ụdị a site na nhazi eletrọnịkị gaa na steeti C 2s22p2, steeti N 2s22p3, steeti Co 3d74s2, steeti H 1 s1, na steeti O 2s22p4. A na-agbakọ ike adsorption na ọdịiche njupụta eletrọn site na iwepụ ike nke usoro gas na ụdị elu site na ike nke sistemụ adsorbed dịka ụdị adsorption ma ọ bụ interface si dị70,71,72,73,74. A na-eji mmezi ike Gibbs free iji gbanwee ike DFT ka ọ bụrụ ike Gibbs free ma na-eburu n'uche onyinye vibration na entropy na ike efu efu75. Ejiri usoro elastic band na-arị elu (CI-NEB) chọọ ọnọdụ mgbanwe nke mmeghachi omume76.
A na-etinye data niile e nwetara ma nyochaa n'oge ọmụmụ ihe a n'isiokwu ahụ na ihe mgbakwunye ma ọ bụ dị n'aka onye dere ya ma ọ bụrụ na ọ rịọ ya. E nyere data isi mmalite maka edemede a.
Koodu niile ejiri mee ihe n'ihe atụ ndị so n'isiokwu a dị n'aka ndị dere ya ma ọ bụrụ na ha rịọ ya.
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