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Ukuklanywa nokuthuthukiswa kwama-catalysts okusebenza okuphezulu sekuthole ukunakwa okukhulu ekuphenduleni okukhethiwe kwe-hydrogenation kodwa kuseyinselelo enkulu.Lapha sibika i-monatomic RuNi alloy (SAA) lapho ama-athomu e-Ru anganyakaziswa khona ebusweni be-Ni nanoparticles ngokusebenzisa i-Ru-Ni coordination, ehambisana nokudluliswa kwe-electron kusuka ku-subsurface i-Ni kuya ku-Ru.Ngolwazi lwethu, i-catalyst ehamba phambili engu-0.4% RuNi SAA ngesikhathi esisodwa ibonise umsebenzi ophezulu (inani le-TOF: 4293 h–1) kanye ne-chemoselectivity ye-hydrogenation ekhethiwe ye-4-nitrostyrene kuya ku-4-aminostyrene (isivuno:> 99%), izinga eliphezulu kakhulu uma kuqhathaniswa nama-catalysts awaziwayo.Ukuhlolwa kwe-in situ kanye nezibalo zethiyori kukhombisa ukuthi amasayithi okuxhumana e-Ru-Ni, njengamasayithi asebenzayo angaphakathi, akhuthaza ukuphulwa okukhethekile kwamabhondi angu-NO ngesivimbeli samandla esiphansi esingu-0.28 eV.Ngaphezu kwalokho, i-synergistic Ru-Ni catalysis ithanda ukwakheka kweziphakathi (C8H7NO* kanye ne-C8H7NOH*) futhi isheshisa isinyathelo sokunquma isilinganiso (hydrogenation of C8H7NOH*).
Ama-amine anephunga elimnandi asebenzayo, izakhi ezibalulekile zamakhemikhali amahle, anemisebenzi ebalulekile yezimboni ekukhiqizeni imithi, amakhemikhali ezolimo, ama-pigments nama-polymers1,2,3.I-catalytic hydrogenation yezinhlanganisela ze-nitroaromatic ezitholakala kalula ngaphezu kwama-catalysts ahlukahlukene kuye kwaheha ukunaka okukhulu njengendlela evumelana nemvelo nengase isetshenziswe kabusha yokuhlanganiswa kwama-amine anevelu eyengeziwe4,5,6,7.Kodwa-ke, ukuncishiswa kwe-chemoselective kwamaqembu -NO2 ngenkathi kugcinwa amanye amaqembu anciphisa njenge-alkenes, alkynes, halogens, noma ama-ketones kuwumsebenzi ofiseleka kakhulu kodwa kunalokho oyinselele8,9,10,11.Ngakho-ke, ukusetshenziswa okunengqondo kwama-catalysts ahlukahlukene ekunciphiseni okuqondile kwamaqembu -NO2 ngaphandle kokuthinta ezinye izibopho ezincishiswayo kufiseleka kakhulu12,13,14.Ama-catalyst amaningi angenansimbi aphenywe ukuze enze i-hydrogenation ye-nitroarenes, kodwa izimo zokusabela ezinzima zivimbela ukusetshenziswa kwazo okubanzi15,16.Nakuba ama-noble metal catalysts (afana ne-Ru17, Pt18, 19, 20 noma Pd21, 22, 23) esebenza ngaphansi kwezimo zokusabela okuthambile, ngokuvamile ahlushwa izindleko eziphakeme, ukukhetha okuncane, kanye nokusetshenziswa okuphansi kwe-athomu.Ngakho-ke, ukuthola ama-catalyst asebenza kakhulu futhi akhetha i-chemoselective ngokuklama okunengqondo nokulungisa kahle isakhiwo esihle kuseyinselelo enkulu24,25,26.
Ama-catalyst e-Monatomic Alloy (SAA) anokusebenza kahle okuphezulu okuphezulu kwensimbi, ukwakheka okukhethekile kwejiyomethri kanye ne-elekthronikhi, ahlinzeka ngeziza ezihlukile ezisebenzayo, futhi anikeze ukusebenza okuvelele kwe-catalytic ngokwephula isici sokuziphatha komugqa wokulinganisa27,28,29,30,31.Ama-athomu awodwa ane-Doped kanye nama-athomu ensimbi abamba e-SAA angasebenza njengezizinda ezimbili ezisebenzayo, enze kube lula ukwenziwa kusebenze kwama-substrates amaningi noma avumele izinyathelo zokusabela eziyisisekelo ezihlukene ukuthi zenzeke kumasayithi ahlukene32,33,34.Ukwengeza, izinhlangano ze-heterometallic phakathi kwama-athomu ensimbi engcolile ehlukanisiwe nezinsimbi zokusingatha zingaholela emiphumeleni ye-idiosyncratic synergistic, nakuba ukuqonda kwemiphumela enjalo ye-synergistic phakathi kwamasethi amabili ezindawo zensimbi ezingeni le-athomu kusalokhu kuyimpikiswano35,36,37,38.Ukuze kusetshenziswe i-hydrogenation ye-nitroarenes esebenzayo, izakhiwo ze-elekthronikhi nezejiyomethri zamasayithi asebenzayo kufanele zakhelwe ngendlela ezosheshisa ukwenziwa kusebenze kwamaqembu e-nitro kuphela.Njengomthetho, amaqembu e-nitro angenayo i-electron adsorbed ikakhulukazi ezindaweni ze-nucleophilic ze-catalyst surface, kuyilapho endleleni elandelayo ye-hydrogenation, i-catalysis yokubambisana yezindawo ezisebenzayo ezingomakhelwane izodlala indima ebalulekile ekulawuleni ukusebenza kabusha kanye ne-chemoselectivity4,25.Lokhu kusishukumisele ukuba sihlole ama-catalyst e-SAA njengekhandidethi elithembisayo lokuthuthukisa ukusebenza kahle kwe-chemoselective hydrogenation ye-nitroaromatic compounds, kanye nokucacisa ngokuqhubekayo ubudlelwano phakathi kwesakhiwo sesizinda esisebenzayo nokusebenza kwe-athomu yesikali sokuvuselela.
Lapha, ama-catalysts asekelwe kuma-alloys e-monatomic RuNi alungiselelwe ngokusekelwe endleleni yokwenziwa yezinyathelo ezimbili, okuhlanganisa ukuguqulwa kwesakhiwo-phezulu se-layer double hydroxide (LDH) elandelwa ukwelashwa kwe-electro-displacement.I-RuNi SAA ibonisa ukusebenza kahle okumangalisayo kwe-catalytic (>99% isivuno) se-chemoselective hydrogenation ye-4-nitrostyrene kuya ku-4-aminostyrene ene-turnover frequency (TOF) efika ku-~4300 mol-mol Ru-1 h-1, ephakeme kakhulu izinga phakathi kwama-catalyst ahlukahlukene abhaliswe ngaphansi kwezimo zokusabela ezifanayo.I-electron microscopy ne-spectroscopic characterization ibonise ukuthi ama-athomu e-Ru ahlukanisiwe ahlakazekile ebusweni be-Ni nanoparticles (~8 nm), akha ukuxhumanisa kwe-Ru-Ni okuzinzile, okuholela kumasayithi we-Ru (Ruδ-) ngenxa yokudluliselwa kwe-electron kusuka ku-subsurface Ni kuya ku-Ru. .Ku-situ FT-IR, izifundo ze-XAFS kanye nezibalo ze-density functional theory (DFT) ziqinisekise ukuthi amasayithi ku-interface ye-Ru-Ni njengamasayithi asebenzayo angaphakathi asiza i-nitro.I-adsorption ecushiwe (0.46 eV) ihlukile kuleyo ye-monometallic nickel catalyst.(0.74 eV).Ngaphezu kwalokho, ukuhlukaniswa kwe-hydrogen kwenzeka ezindaweni ezingomakhelwane ze-Ni, kulandelwa i-hydrogenation of intermediates (C8H7NO* kanye ne-C8H7NOH*) ezikhundleni ze-Ruδ.Umthelela we-synergistic we-doping yokusekela ku-catalyst ye-RuNi SAA iphumela emsebenzini ovelele we-nitroarenes hydrogenation kanye nokukhetha, okunganwetshwa kwamanye ama-catalysts ensimbi angavamile asetshenziswa ekwakheni ukusabela okubucayi.
Ngokusekelwe ekushintsheni kwe-topology yesakhiwo se-layer double hydroxide (LDH) izandulela, silungise i-monometallic Ni efakwe kuma-amorphous Al2O3 substrates.Ngemva kwalokho, isethi yamasampuli e-RuNi/Al2O3 bimetallic anokuqukethwe okuhlukile kwe-Ru (0.1–2 wt %) yahlanganiswa ngokunembile ngokufakwa kwe-electrodisplacement ukuze kufakwe ama-athomu e-Ru ebusweni be-Ni nanoparticles (NPs) (Fig. 1a).Izilinganiso ze-plasma atomic emission spectrometry (ICP-AES) ezihlanganiswe ngendlela engokwemvelo zinikeze ngokusobala ukwakheka okuyisisekelo kwe-Ru ne-Ni kulawa masampuli (Ithebula Lokwengeza 1), eliseduze nokulayishwa kwesitoko sethiyori.Izithombe ze-SEM (Umfanekiso Owengeziwe 1) kanye nemiphumela ye-BET (Izibalo Ezingeziwe 2-9 kanye neThebula Lokwengeza 1) zibonisa ngokucacile ukuthi isakhiwo se-morphological kanye nendawo ethile yendawo yamasampula e-RuNi/Al2O3 ayenzi izinguquko ezisobala ngesikhathi sokwelashwa kwe-electrochemical.– inqubo yokuhamba.Iphethini ye-X-ray (Fig. 1b) ibonisa uchungechunge lwezimpawu zokubonisa ku-2θ 44.3°, 51.6°, kanye no-76.1°, okubonisa izigaba (111), (200), kanye (220) ze-Ni ejwayelekile (JCPDS 004–0850 ).Ngokuphawulekayo, amasampula e-RuNi awabonisi ukuvela kwe-metallic noma i-oxidized Ru, okubonisa ukusakazeka okuphezulu kwezinhlobo ze-Ru.Izilinganiso ze-electron microscopy (TEM) zokudlulisa amasampula e-monometallic Ni ne-RuNi (Fig. 1c1–c8) zibonisa ukuthi ama-nanoparticles e-nickel ahlakazeke kahle futhi awanyakazi ekusekelweni kwe-amorphous Al2O3 enosayizi wezinhlayiyana ezifanayo (7.7–8.3 nm).Izithombe ze-HRTEM (Amakhiwane 1d1-d8) abonisa isikhathi se-lattice esifanayo esingaba ngu-0.203 nm kumasampula e-Ni ne-RuNi, ahambisana nezindiza ze-Ni(111), nokho, imiphetho ye-lattice yezinhlayiya ze-Ru azikho.Lokhu kukhombisa ukuthi ama-athomu e-Ru ahlakazeke kakhulu endaweni yesampula futhi ayithinti isikhathi se-Ni lattice.Phakathi naleso sikhathi, i-2 wt% i-Ru/Al2O3 yahlanganiswa ngendlela ye-deposition-deposition njengendlela yokulawula, lapho amaqoqo e-Ru asakazwa ngokufanayo ebusweni be-substrate ye-Al2O3 (I-Supplementary Figs. 10-12).
i-Scheme yomzila wokuhlanganisa wamasampula e-RuNi/Al2O3, b amaphethini wokuphambuka kwe-X-ray we-Ni/Al2O3 kanye namasampuli ahlukahlukene e-RuNi/Al2O3.c1−c8 TEM kanye ne-d1−d8 HRTEM izithombe zegrayiti ezinokusabalalisa kosayizi wezinhlayiyana ngokulandelana kwe-monometallic Ni, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0, 8% wt., 1 wt.Isithombe esinemigqa.% kanye no-2 wt.% RuNi.“au” kusho amayunithi angenasizathu.
Umsebenzi we-catalytic wamasampuli we-RuNi wafundwa nge-chemoselective hydrogenation ye-4-nitrostyrene (4-NS) kuya ku-4-aminostyrene (4-AS).Ukuguqulwa kwe-4-NS ku-substrate ehlanzekile ye-Al2O3 kwaba ngu-0.6% kuphela ngemva kwamahora angu-3 (Ithebula Elingeziwe 2), okubonisa umphumela omncane we-catalytic we-Al2O3.Njengoba kuboniswe emkhiwaneni.2a, i-nickel catalyst yasekuqaleni ibonise umsebenzi we-catalytic ophansi kakhulu ngokuguqulwa kwe-4-NS kuka-7.1% ngemva kwamahora angu-3, ​​kuyilapho ukuguqulwa okungu-100% kungafinyelelwa phambi kwe-monometallic Ru catalyst ngaphansi kwezimo ezifanayo.Wonke ama-catalysts we-RuNi abonise umsebenzi we-hydrogenation okhuphuke kakhulu (ukuguqulwa: ~ 100%, 3 h) uma kuqhathaniswa namasampula e-monometallic, futhi izinga lokuphendula lalihlotshaniswa kahle nokuqukethwe kwe-Ru.Lokhu kusho ukuthi izinhlayiya ze-Ru zidlala indima ebalulekile enqubweni ye-hydrogenation.Kuyathakazelisa ukuthi ukukhetha komkhiqizo (Fig. 2b) kuyahlukahluka kuye ngokuthi i-catalyst.Nge-catalyst ehlanzekile ye-nickel engasebenzi, umkhiqizo oyinhloko wawuyi-4-nitroethylbenzene (4-NE) (ukukhethwa: 83.6%) kanye nokukhethwa kwe-4-AC kwaba ngu-11.3%.Endabeni ye-Ru monometallic, isibopho se-C=C ku-4-NS singase sibe lula ku-hydrogenation kune-NO2, okuholela ekwakhekeni kwe-4-nitroethylbenzene (4-NE) noma i-4-aminoethyl benzene (4-AE);ukukhetha kwe-4-AC kwaba ngu-15.7% kuphela.Ngokumangalisayo, i-RuNi catalysts enokuqukethwe okuphansi kwe-Ru (0.1-0.4 wt%) ibonise ukukhetha okuhle kakhulu (> 99%) kuya ku-4-aminostyrene (4-AS), okubonisa ukuthi i-NO2 hhayi i-vinyl, i-chemoselective eyingqayizivele.Lapho okuqukethwe kwe-Ru kudlula i-0.6 wt.%, ukukhetha kwe-4-AS kwehle kakhulu ngokulayisha okwandayo kwe-Ru, kuyilapho ukukhethwa kwe-4-AE kwanda esikhundleni.Ku-catalyst equkethe i-2 wt% i-RuNi, amaqembu womabili we-nitro ne-vinyl ayenziwe nge-hydrogenated kakhulu ngokukhetha okuphezulu ku-4-AE ye-98%.Ukutadisha umthelela wesimo sokuhlakazeka kwe-Ru ekuphenduleni kwe-catalytic, amasampuli angu-0.4 wt% Ru/Al2O3 alungiswa (Izibalo Ezingeziwe 10, 13 kanye no-14) lapho izinhlayiya ze-Ru zazihlakazwa khona kakhulu njengama-athomu angawodwana alandelwa amaqoqo ama-Ru ambalwa.(i-quasi-atomic Ru).Ukusebenza kwe-catalytic (Ithebula Le-Supplementary 2) kubonisa ukuthi i-0.4 wt% Ru/Al2O3 ithuthukisa ukukhetha kwe-4-AS (67.5%) uma kuqhathaniswa nesampula ye-2 wt% Ru/Al2O3, kodwa umsebenzi uphansi kakhulu (ukuguqulwa: 12.9).%;3 amahora).Ngokusekelwe enanini eliphelele lezindawo zensimbi endaweni enqunywe izilinganiso ze-CO pulsed chemisorption, imvamisa ye-turnover (TOFmetal) ye-RuNi catalyst itholwe ekuguquleni okuphansi kwe-4-NS (I-Supplementary Fig. 15), ebonise ukuthambekela kokuqala ukwanda bese wehla ngokukhula okwandayo ekulayisheni kwe-Ru (I-Supplementary Fig. 16).Lokhu kuphakamisa ukuthi akuzona zonke izingosi zensimbi ezisebenza njengezindawo ezisebenzayo ze-RuNi catalysts.Ngaphezu kwalokho, i-TOF ye-catalyst ye-RuNi yabalwa kusukela kumasayithi we-Ru ukuze iqhubeke iveze umsebenzi wayo we-catalytic wangaphakathi (Fig. 2c).Njengoba okuqukethwe kwe-Ru kukhuphuka kusuka ku-0.1 wt.% ukuya ku-0.4 wt.% Ama-catalysts we-RuNi abonise amanani we-TOF cishe angashintshi (4271-4293 h–1), okubonisa ukwenziwa kwasendaweni kwezinhlayiya ze-Ru ekuhlakazweni kwe-athomu (mhlawumbe ngokwakhiwa kwe-RuNi SAA).) futhi isebenza njengendawo eyinhloko esebenzayo.Kodwa-ke, ngokunyuka okuqhubekayo kokulayishwa kwe-Ru (ngaphakathi kwe-0.6-2 wt%), inani le-TOF liyancipha kakhulu, okubonisa ukuguqulwa kwesakhiwo sangaphakathi sesikhungo esisebenzayo (kusuka ekuhlakazekeni kwe-athomu kuya ku-Ru nanoclusters).Ngaphezu kwalokho, ngokwazi kwethu, i-TOF ye-0.4 wt% RuNi (SAA) catalyst isezingeni eliphezulu kakhulu phakathi kwama-catalysts ensimbi abikwe ngaphambilini ngaphansi kwezimo zokusabela ezifanayo (Ithebula le-Supplementary Table 3), ebonisa ngokuqhubekayo ukuthi ama-alloys e-monoatomic RuNi ahlinzeka ngezakhiwo ezinhle kakhulu ze-catalytic.umbukwane.Umfanekiso ongeziwe we-17 ubonisa ukusebenza kwe-catalytic kwe-0.4 wt% RuNi (SAA) catalyst ezicindezelweni ezihlukahlukene namazinga okushisa e-H2, lapho ukucindezela kwe-H2 kwe-1 MPa kanye nezinga lokushisa elingu-60 °C lisetshenziswe njengemingcele yokusabela efanele.isampula equkethe i-RuNi 0.4 wt.% (I-Fig. 2d), futhi akukho ukwehla okuphawulekayo komsebenzi kanye nesivuno esibonwe phezu kwemijikelezo emihlanu elandelanayo.Izithombe ze-X-ray ne-TEM ze-0.4 wt% i-RuNi catalyst esetshenziswe ngemva kwemijikelezo ye-5 (Izibalo Ezingeziwe 18 no-19) azizange zibonise izinguquko eziphawulekayo esakhiweni se-crystal, okubonisa ukuzinza okuphezulu kokusabela okukhethiwe kwe-hydrogenation.Ukwengeza, i-catalyst ye-0.4 wt% ye-RuNi (SAA) iphinde inikeze izivuno ezinhle kakhulu zama-amine ze-chemoselective hydrogenation yamanye ama-nitroaromatic compounds aqukethe ama-halogen, ama-aldehydes, namaqembu e-hydroxyl (Ithebula le-Supplementary 4), ekhombisa ukusebenza kahle kwayo.
ukuguqulwa kwe-Catalytic kanye nokusabalalisa b kwemikhiqizo ye-4-nitrostyrene hydrogenation phambi kwe-monometallic Ni, Ru, ne-RuNi catalysts enokuqukethwe okuhlukile kwe-Ru (0.1–2 wt %), c ku-catalytic dynamic range, Turnover frequency (TOF) ku-RuNi ama-catalysts c kuye ngokuthi Ru ngemvukuzane.d Hlola ukuthi kungenzeka yini ukusetshenziswa kabusha kwe-0.4 wt.% I-RuNi catalyst yemijikelezo emihlanu elandelanayo ye-catalytic.I-ln (C0/C) isekelwe esikhathini sokusabela se-hydrogenation ye-e-nitrobenzene ne-f-styrene ngengxube ye-nitrobenzene ne-styrene (1:1).Izimo zokusabela: 1 mmol reagent, 8 ml solvent (ethanol), 0.02 g catalyst, 1 MPa H2, 60°C, amahora angu-3.Amabha amaphutha achazwa njengokuchezuka okujwayelekile kwezimpinda ezintathu.
Ukuze kuqhutshekwe kuphenywe umehluko obalulekile we-chemoselective, i-hydrogenation yengxube ye-styrene ne-nitrobenzene (1:1) nayo yenziwa phambi kwe-monometallic catalysts Ni, Ru, 0.4 wt% RuNi, kanye no-2 wt% RuNi, ngokulandelana (Supplementary Fig. .Nakuba i-chemoselectivity ye-reaction hydrogenation yamaqembu asebenzayo ihambisana, ngempela kukhona umehluko ekukhetheni kwe-intramolecular kanye ne-intermolecular hydrogenation ngenxa yemiphumela ye-allosteric yamangqamuzana.Njengoba kuboniswe emkhiwaneni.2e,f, ijika ln(C0/C) ngokumelene nesikhathi sokusabela kunikeza umugqa oqondile osuka kumvelaphi, okubonisa ukuthi kokubili i-nitrobenzene ne-styrene kuwukusabela kwe-oda lokuqala mbumbulu.I-Monometallic nickel catalysts ibonise isilinganiso esiphansi kakhulu se-hydrogenation rate yakho kokubili i-p-nitrobenzene (0.03 h-1) kanye ne-styrene (0.05 h-1).Ngokuphawulekayo, umsebenzi okhethwayo we-styrene hydrogenation (izinga elilinganayo: 0.89 h-1) wazuzwa ku-Ru monometallic catalyst, ephakeme kakhulu kunomsebenzi we-nitrobenzene hydrogenation (izinga elilinganayo: 0.18 h-1).Endabeni ye-catalyst equkethe i-RuNi(SAA) 0.4 wt.I-% i-nitrobenzene hydrogenation ithandeka kakhulu kune-styrene hydrogenation (izinga elilinganayo: 1.90 h-1 vs. 0.04 h-1), okubonisa okuthandwayo kweqembu -NO2.phezu kwe-C hydrogenation = isibopho C. Ukuze uthole i-catalyst ene-2 ​​wt.% RuNi, izinga elingaguquki le-hydrogenation ye-nitrobenzene (1.65 h-1) lehlile uma liqhathaniswa no-0.4 wt.% I-RuNi (kodwa isephezulu kunaleyo ye-mono-metal catalyst), kuyilapho izinga le-hydrogenation ye-styrene landa kakhulu (izinga elilinganayo: 0.68).h−1).Lokhu futhi kubonisa ukuthi ngomphumela we-synergistic phakathi kwe-Ni ne-Ru, umsebenzi we-catalytic kanye ne-chemoselectivity ukuya kumaqembu we-NO2 akhuphuka kakhulu uma kuqhathaniswa ne-RuNi SAA.
Ukuze unqume ngokubukeka izimo zokuhlakazeka zenhlanganisela ye-Ru kanye ne-Ni, indlela yokucabanga esebenzisa i-electron microscopy ye-engeli ephezulu yokuskena emnyama ngokulungiswa kwe-aberration (AC-HAADF-STEM) kanye nemephu yesici nge-energy dispersive spectroscopy (EDS) yenziwa.Imephu eyisisekelo ye-EMF yesampula enokuqukethwe okungu-0.4 wt% kwe-RuNi (Fig. 3a, b) ibonisa ukuthi i-Ru ihlakazeke kakhulu ngokulinganayo ku-nickel nanoparticles, kodwa hhayi ku-substrate ye-Al2O3, isithombe esihambisanayo se-AC-HAADF-STEM (Fig. 3c) imibukiso, Kungabonakala ukuthi ingaphezulu le-Ni NPs liqukethe izindawo eziningi ezikhanyayo zesayizi ye-athomu yama-athomu e-Ru (amakwe ngemicibisholo eluhlaza okwesibhakabhaka), kuyilapho kungabonwa amaqoqo noma ama-Ru nanoparticles.Fig. 3d), ebonisa ukwakheka kwe-monatomic RuNi alloys.Ukuze uthole isampula equkethe i-RuNi 0.6 wt.I-% (Fig. 3e), ama-athomu e-Ru eyodwa kanye nenani elincane lezinhlayiya ze-Ru eziningi zabonwa kuma-Ni NPs, okubonisa ukuhlanganiswa okuncane kwama-athomu e-Ru ngenxa yomthwalo owandayo.Endabeni yesampula enokuqukethwe kwe-2 wt% ye-RuNi, amaqoqo amaningi ama-Ru amakhulu ku-Ni NPs atholakala esithombeni se-HAADF-STEM (Fig. 3f) kanye ne-EDS elemental mapping (Supplementary Fig. 21), ebonisa ukuqoqwa okukhulu kwe-Ru. .
isithombe se-HAADF-STEM, b isithombe esihambisanayo semephu ye-EDS, c isithombe sokucaca okuphezulu se-AC-HAADF-STEM, d isithombe se-STEM esikhulisiwe nokusabalalisa okuhambisanayo kokuqina kwesampula ye-RuNi engu-0.4 wt%.(e, f) AC–HAADF–STEM izithombe zamasampuli aqukethe 0.6 wt.% I-RuNi kanye ne-2 wt.% I-RuNi, ngokulandelana.
Uma kuqhathaniswa namasampuli e-Ni/Al2O3 kanye ne-Ru/Al2O3, i-spectra ye-DRIFTS ye-CO adsorption in situ yenziwe (Fig. 4a) ukuze kuqhutshekwe kufundwe imininingwane yesakhiwo samasampuli aqukethe i-0.4 wt.%, 0.6 wt.% kanye no-2 wt.% I-RuNi.Ukukhangisa kwe-CO kusampula ye-Ru/Al2O3 kunikeza inani eliphakeme eliphakeme elingu-2060 cm-1 kanye nelinye inani eliphakeme elibanzi elingu-1849 cm-1 okubangelwa umugqa we-CO adsorption ku-Ru kanye nokuhlanganisa ama-athomu amabili e-Ru angomakhelwane, ngokulandelana kwawo i-CO39,40.Kusampula ye-Monometallic Ni, ukuphakama okuqinile kubonakala kuphela ku-2057 cm–1, okubangelwa umugqa we-CO41,42 esifundeni se-nickel.Kusampula ye-RuNi, ngaphezu kwesiqongo esiyinhloko ku-2056 cm-1, kukhona ihlombe elihlukile eligxile ku-~2030 cm-1.Indlela ye-Gaussian yokufaka i-peak fitting yasetshenziswa ukuze kukhishwe ngokunengqondo ukusatshalaliswa kwamasampula e-RuNi ebangeni le-2000-2100 cm-1 kanye nokusatshalaliswa kwe-CO endaweni ye-Ni (2056 cm-1) kanye nesifunda se-Ru (2031-2039 cm).Iziqongo ezimbili zazikhangisiwe ngokulinganayo - 1) (Fig. 4b).Kuyathakazelisa ukuthi kusukela kumasampula e-Ru/Al2O3 (2060 cm–1) kuya kumasampula e-RuNi (2031–2039 cm–1), ukuphakama kwe-CO okuhlobene ngokuqondile esifundeni se-Ru kushintshe kakhulu futhi kuyanda ngokwanda kokuqukethwe kwe-Ru.Lokhu kubonisa ukwanda kwe-electronegativity yezinhlayiya ze-Ru kusampula ye-RuNi, okuwumphumela wokudluliselwa kwama-electron ukusuka ku-Ni kuya ku-Ru, okwandisa impendulo ye-electron ye-d-π isuka ku-Ru iye ku-antibonding CO 2π* orbital.Ukwengeza, kusampula equkethe i-0.4 mass% i-RuNi, akukho ukuphakama kwe-adsorption ye-bridging ebonwe, okubonisa ukuthi izinhlayiya ze-Ru zikhona njengama-athomu e-Ni ahlukene (SAA).Endabeni yamasampula ane-0.6 wt.% I-RuNi kanye ne-2 wt.% I-RuNi, ukuba khona kwe-CO bridging kuqinisekisa ukuba khona kwama-Ru multimers noma amaqoqo, okuvumelana kahle nemiphumela ye-AC-HAADF-STEM.
i-In situ CO-DRIFTS spectra ye-Ni/Al2O3, Ru/Al2O3 kanye ne-0.4 wt.%, 0.6 wt.%, 2 wt.% amasampula e-RuNi anegesi ye-helium egeleza kububanzi obungu-2100–1500 cm-1 imizuzu engu-20.b Isibukeli esilinganisiwe nesifakwe i-Gaussian sesampuli ye-RuNi/Al2O3 enezindawo eziphakeme ezigxilile kanye ne-FWHM.c In situ Ru K-edge XANES spectra kanye ne-d EXAFS Fourier iguqula i-spectra yamasampuli ahlukahlukene.Ukuguqulwa kwe-wavelet enesisindo se-K2 yamasiginali we-XAFS K-edge Ru asuselwa ku-wavelet ye-Morlet yamasampula e-e Ru avela ku-e Ru foil, f 0.4 wt% RuNi kanye ne-g RuO2.“au” kusho amayunithi angenasizathu.
Isakhiwo se-X-ray esijwayelekile sokumuncwa kwesakhiwo se-X-ray (i-XANES) senziwe ukuze kufundwe izakhiwo ze-elekthronikhi nezejiyomethri zamasampula e-RuNi ngamasampula e-Ru foil kanye ne-RuO2.Njengoba kuboniswe emkhiwaneni.4c, njengoba ukulayisha kwe-Ru kuncipha, ukushuba komugqa omhlophe kancane kancane kuncipha ukusuka kumasampuli we-Ru/Al2O3 ukuya kumasampuli we-RuNi.Ngaleso sikhathi, ukushuba komugqa omhlophe we-spectrum ye-XANES ku-K-edge ye-Ni kubonisa ukukhuphuka okuncane ukusuka kusampula ye-Ni yangempela kuya kusampula ye-RuNi (I-Supplementary Fig. 22).Lokhu kukhombisa uguquko kubuningi be-electron kanye nemvelo yokuxhumana yezinhlanganisela ze-Ru.Njengoba kuboniswe ku-spectra ye-X-ray photoelectron spectroscopy (XPS) (I-Supplementary Fig. 23), ukuphakama kwe-Ru0 yesampula ye-RuNi kushintshele kumandla aphansi okubopha futhi ukuphakama kwe-Ni0 kushintshele kumandla aphezulu okubopha uma kuqhathaniswa ne-monometallic Ru ne-Ni., okubonisa ngaphezu kwalokho ukudluliswa kwama-electron ukusuka kuma-athomu e-Ni kuya kuma-athomu e-Ru e-RuNi SAA.Ukuhlaziywa kweshaja ye-Bader yendawo ye-RuNi SAA(111) kubonisa ukuthi ama-athomu e-Ru ahlukanisiwe athwala amashaji angemahle (Ruδ-) adluliswa esuka endaweni engaphansi komhlaba ye-Ni atoms (I-Supplementary Fig. 24), ehambisana ne-in situ DRIFTS nemiphumela ye-XPS.Ukuze sifunde kabanzi ngesakhiwo sokuxhumanisa se-Ru (Fig. 4d), senze i-X-ray enwetshiwe yokumuncwa i-spectroscopy (EXAFS) kuguquko lwe-Fourier.Isampuli equkethe i-RuNi 0.4 wt.I-% inenani eliphakeme elicijile kokuthi ~2.1 Å, elitholakala esifundeni esiphakathi kwamagobolondo e-Ru-O (1.5 Å) kanye ne-Ru-Ru (2.4 Å), okungamalulwe ku-Ru-Ni coordination44, 45. Imiphumela yokulingana kwedatha EXAFS (Ithebula Lokwengeza 5 kanye Nezibalo Ezingeziwe 25-28) zibonisa ukuthi indlela ye-Ru-Ni inenombolo yokuxhumanisa (CN) ye-5.4, kuyilapho kungekho ukuxhumana kwe-Ru-Ru ne-Ru-O ku-0.4 wt.% Isampula ye-RuNi.Lokhu kuqinisekisa ukuthi ama-athomu ama-Ru ayinhloko ahlakazekile nge-athomu futhi azungezwe yi-Ni, enza i-alloy monoatomic.Kufanele kuqashelwe ukuthi ukuqina okuphezulu (~2.4 Å) kokuxhumana kwe-Ru-Ru kubonakala kusampula ye-0.6 wt.% RuNi futhi ithuthukiswa kusampula ngo-2 wt.% I-RuNi.Ikakhulukazi, ukufakwa kwejika kwe-EXAFS kubonise ukuthi izinombolo zokuxhumanisa i-Ru-Ru zikhuphuke kakhulu zisuka ku-0 (0.4 wt.% RuNi) zaya ku-2.2 (0.6 wt.% RuNi) futhi zanda zafinyelela ku-6.7 (2 wt.% .% RuNi), ngokulandelana. , okubonisa ukuthi njengoba umthwalo we-Ru ukhula, ama-athomu akwa-Ru ahlangana kancane kancane.I-K2-weighted wavelet transform (WT) yamasiginali we-Ru K-edge XAFS yaphinde yasetshenziswa ukutadisha indawo yokuxhumanisa yezinhlobo ze-Ru.Njengoba kuboniswe emkhiwaneni.I-4e, i-Ru foil lobes ku-2.3 Å, 9.7 Å-1 ibhekisela kumnikelo we-Ru-Ru.Kusampula equkethe i-RuNi 0.4 wt.% (Fig. 4f) awekho amalobe ku-k = 9.7 Å-1 kanye no-5.3 Å-1, ngaphandle kwebhondi emaphakathi ye-Ru nama-athomu ka-Ru kanye nama-athomu e-O (Fig. 4g);I-Ru-Ni ibhekwa ku-2.1 Å, 7.1 Å-1, okufakazela ukwakheka kwe-SAA.Ngaphezu kwalokho, i-spectra ye-EXAFS ku-K-edge ye-Ni yamasampula ahlukene ayizange ibonise umehluko obalulekile (I-Supplementary Fig. 29), ebonisa ukuthi ukwakheka kokuxhumana kwe-Ni akuthonywa kancane ngama-athomu e-Ru.Ngamafuphi, imiphumela ye-AC-HAADF-STEM, in situ CO-DRIFTS, kanye nokuhlolwa kwe-XAFS ku-situ kuqinisekisile ukulungiswa ngempumelelo kwama-catalysts e-RuNi SAA kanye nokuvela kwezinhlayiya ze-Ru kuma-Ni NPs ukusuka ku-athomu eyodwa kuya kuma-multimers e-Ru ngokwandisa Ru layisha.Ngaphezu kwalokho, izithombe ze-HAADF-STEM (i-Supplementary Fig. 30) kanye ne-EXAFS spectra (Fig. 31) ye-RuNi SAA catalysts esetshenzisiwe ibonise ukuthi isimo sokuhlakazeka kanye nesakhiwo sokuxhumanisa ama-athomu we-Ru akuzange kushintshe kakhulu ngemva kwemijikelezo ye-5, okufakazela. ukuthi i-RuNi SAA catalyst ezinzile.
Izilinganiso ze-H2-TPD zenziwa ukuze kufundwe i-adsorption ye-dissociative ye-hydrogen kuma-catalysts ahlukahlukene futhi imiphumela ibonise ukuthi zonke lezi zici zinamandla okuhlukanisa i-H2 nge-desorption peak ku ~ 100 ° C (Supplementary Fig. 32).Imiphumela yokuhlaziywa kobuningi (I-Supplementary Fig. 33) ayizange ibonise ukuhlobana okucacile komugqa phakathi kokusebenza kabusha kanye nenani le-hydrogen desorption.Ukwengeza, senze izivivinyo nge-D2 isotopes futhi sathola inani le-kinetic isotope effect (KIE) le-1.31 (TOFH/TOFD) (I-Supplementary Fig. 34), esikisela ukuthi ukusebenza nokuhlukaniswa kwe-H2 kubalulekile kodwa hhayi izinyathelo zokukhawulela izinga.Izibalo ze-DFT zenziwa ukuze kuqhutshekwe kuphenywe ngokuziphatha kwe-adsorption nokuhlukaniswa kwe-hydrogen ku-RuNi SAA ngokumelene ne-Metallic Ni yodwa (I-Supplementary Fig. 35).Kumasampuli e-RuNi SAA, ama-molecule e-H2 akhetha i-chemisorb kune-athomu ye-Ru eyodwa enamandla e-adsorption angu- -0.76 eV.Kamuva, i-hydrogen iyahlukana ibe ama-athomu amabili e-H asebenzayo ezindaweni ezingenalutho ze-Ru-Ni RuNi SAA, inqoba umgoqo wamandla ongu-0.02 eV.Ngokungeziwe kumasayithi we-Ru, ama-molecule e-H2 angaphinde afakwe ku-chemisorbed ezindaweni ezingenhla ze-Ni athomu eziseduze ne-Ru (amandla e-adsorption: -0.38 eV) abese ehlukaniswa abe ama-H amabili ezindaweni ezingenalutho ze-Ru-Ni kanye ne-Ni-Ni.Isithiyo se-atomic 0.06 eV.Ngokuphambene, izithiyo zamandla zokukhangisa nokuhlukaniswa kwama-molecule e-H2 endaweni ye-Ni(111) ingu -0.40 eV kanye no-0.09 eV, ngokulandelanayo.Isithiyo samandla esiphansi kakhulu kanye nomehluko ongabalulekile ubonisa ukuthi i-H2 ihlukanisa kalula ebusweni be-Ni ne-RuNi surfactants (i-Ni-site noma i-Ru-site), okungeyona into ebalulekile ethinta umsebenzi wayo we-catalytic.
I-adsorption eyenziwe yasebenza yamaqembu athile asebenzayo ibalulekile ekukhetheni i-hydrogenation yama-substrates.Ngakho-ke, senze izibalo ze-DFT ukuze siphenye ukulungiselelwa okungenzeka kwe-4-NS adsorption namasayithi asebenzayo endaweni ye-RuNi SAA(111), futhi imiphumela yokuthuthukisa iboniswa ku-Supplementary Fig. 36. Ukucushwa okubonakala kufana (Fig. 5a kanye ne-Supplementary Fig. 36e), lapho ama-athomu angu-N atholakala ezindaweni ezingenalutho ze-Ru-Ni futhi ama-athomu amabili e-O ahlanganiswe ku-interface ye-Ru-Ni abonisa izinga eliphansi lamandla e-adsorption (-3.14 eV).Lokhu kuphakamisa isimiso se-adsorption esivumayo ngokwe-thermodynamically uma kuqhathaniswa nokuma okuqondile nokunye ukulungiselelwa okufanayo (I-Supplementary Fig. 36a–d).Ngaphezu kwalokho, ngemva kokukhangiswa kwe-4-HC ku-RuNi SAA(111), ubude bebhondi ye-N-O1 (L(N-O1)) eqenjini le-nitro bukhuphuke baba ngu-1.330 Å (Fig. 5a), okuyinto eningi. ubude kunobude be-gaseous 4- NS (1.244 Å) (I-Supplementary Fig. 37), ngisho nokudlula i-L (N-O1) (1.315 Å) ku-Ni (111).Lokhu kubonisa ukuthi i-adsorption eyenziwe yasebenza yamabhondi e-N–O1 ebusweni be-RuNi PAA ithuthukiswe kakhulu uma iqhathaniswa ne-Ni(111) yokuqala.
ukulungiselelwa kwe-Adsorption ye-4-HC endaweni ye-Ni(111) ne-RuNi SAA(111) (Eads) (ukubuka okuseceleni nokuphezulu).Ru – violet, Ni – green, C – orange, O – red, N – blue, H – white.b In situ FT-IR spectra of gaseous and chemisorbed 4-HC kuma-monometallic surfactants Ni, Ru, RuNi (0.4 wt. %) kanye no-2 wt.% I-RuNi, ngokulandelana.c Ijwayeleke endaweni XANES kanye ne-d-phase-elungiswe i-Fourier EXAFS ku-Ru K-edge ka-0.4 wt % RuNi PAA ngesikhathi se-4-NS adsorption (RuNi SAA–4NS) nezinyathelo ze-hydrogenation (RuNi SAA–4NS–H2) .Isibukeli soguquko ;…e Ukuminyana kwezifundazwe (i-PDOS) yendawo yokuqala ye-RuNi SAA(111), N-O1 ku-4-NS enegesi kanye ne-adsorbed 4-NS ku-RuNi SAA(111).“au” kusho amayunithi angenasizathu.
Ukuze kuqhutshekwe nokuhlola ukuziphatha kwe-adsorption ye-4-NS, ku-situ izilinganiso ze-FT-IR zenziwe ku-Ni monometallic, Ru monometallic, 0.4 wt% RuNi (SAA), kanye ne-2 wt% RuNi catalysts (Fig. 5b).I-spectrum ye-FT-IR ye-gaseous 4-NS ibonise iziqongo zesici ezintathu ku-1603, 1528, kanye ne-1356 cm-1, eyabelwa u-ν(C=C), νas(NO2), kanye ne-νs(NO2)46,47, 48.Lapho kukhona i-Monometallic Ni, ama-redshift awo womathathu amabhendi ayabonwa: v(C=C) (1595 cm–1), νas(NO2) (1520 cm–1), kanye no-νs(NO2) (1351 cm–1) ., okubonisa i-chemisorption yamaqembu e-C=C kanye -NO2 endaweni ye-Ni (okungenzeka kakhulu, ekucushweni kwe-parallel adsorption).Ukuze uthole isampula ye-monometallic Ru, ama-redshift alawa mabhendi amathathu (1591, 1514, kanye no-1348 cm–1, ngokulandelana) ahlobene ne-monometallic Ni atholwe, okubonisa ukukhangisa okuthuthukisiwe kwamaqembu e-nitro namabhondi С=С ku-Ru.Esimweni se-0.4 wt.I-% RuNi (SAA), ibhendi ye-ν(C=C) igxile ku-1596 cm–1, esondelene kakhulu ne-monometallic Ni band (1595 cm–1), okubonisa ukuthi amaqembu e-vinyl ajwayele ukukhangisa u-Ni on the RuNi. Izingosi ze-SAA.Ngaphezu kwalokho, ngokungafani ne-monometallic catalyst, ukuqina okuhlobene kwebhendi ye-νs(NO2) (1347 cm-1) ibuthakathaka kakhulu kunebhendi ye-νas(NO2) (1512 cm-1) ku-0.4 wt.% RuNi (SAA) ) , okuhlotshaniswa nokuqhekeka kwesibopho se-NO ku-NO2 ukuze kwakhiwe i-nitroso ephakathi ngokuvumelana nezifundo zangaphambilini49,50.Kuphinde kwabonwa into efanayo kusampula enokuqukethwe kwe-RuNi okungu-2 wt.%.Imiphumela engenhla iqinisekisa ukuthi umphumela we-synergistic wezikhungo ze-bimetallic ku-PAA RuNi ukhuthaza ukuhlukaniswa nokuhlukaniswa kwamaqembu e-nitro, okuvumelana kahle nokucushwa kwe-adsorption okuphelele okutholwe izibalo ze-DFT.
I-spectroscopy ye-in situ XAFS yenzelwa ukutadisha ukuguquguquka okuguquguqukayo kwesakhiwo se-elekthronikhi nesimo sokuxhumanisa se-RuNi SAA ngesikhathi se-4-NS adsorption kanye ne-catalytic reaction.Njengoba kungabonwa ku-K-edge XANES spectrum ye-Ru (Fig. 5c), ngemva kokukhangiswa kwe-4-HC, 0.4 wt.% I-RuNi PAA, unqenqema lokumuncwa lushintshelwa kakhulu emandleni aphezulu, okuhambisana nokwanda kokuqina komugqa omhlophe, okubonisa ukuthi uhlobo lwe-Ru I-oxidation eyingxenye yenzeke ngenxa yokudluliselwa kwe-electron kusuka ku-Ru kuya ku-4-NS.Ukwengeza, i-Fourier elungiswe ngesigaba iguqule i-EXAFS spectrum ye-adsorbed 4-NS RuNi SAA (Fig. 5d) ibonisa ukuthuthukiswa okucacile kwamasignali kokuthi ~1.7 Å kanye no-~3.2 Å, okuhlotshaniswa nokwakhiwa kokuxhumana kwe-Ru-O.I-spectra ye-XANES ne-EXAFS ye-0.4 wt% RuNi SAA ibuyele esimweni sayo sasekuqaleni ngemva kokujova imizuzu engu-30 yegesi ye-hydrogen.Lezi zenzakalo zibonisa ukuthi amaqembu e-nitro akhangiswa kumasayithi we-Ru ngamabhondi e-Ru-O asekelwe ekusebenzisaneni ngogesi.Ngokuqondene ne-spectra ye-XAFS yonqenqema lwe-Ni-K ku-situ (I-Fig. 38 Eyengeziwe), azikho izinguquko ezisobala eziboniwe, okungenzeka kungenxa yomphumela wokuhlanjululwa kwama-athomu e-Ni esigabeni sobuningi ezinhlayiyeni ze-Ni ezingaphezulu.Ukuminyana okubikezelwe kwezifunda (PDOS) ze-RuNi SAA (Fig. 5e) kukhombisa ukuthi isimo sokungahlali muntu seqembu le-nitro ngaphezu kwezinga le-Femi siyanwebeka futhi sihambe ngaphansi kwezinga le-Femi esimweni se-adsorbed, okubonisa ngaphezu kwalokho ukuthi ama-electron asuka ku-d- isimo se-RuNi SAA sishintshela esimweni esingahlali muntu e-−NO2.Umehluko we-charge density (I-Supplementary Fig. 39) kanye nokuhlaziywa kwe-Bader charge (I-Supplementary Fig. 40) kubonisa ukuthi ukuminyana kwe-electron ehlanganisiwe ye-4-NS iqoqa ngemva kokukhangiswa kwayo ebusweni be-RuNi SAA (111).Ukwengeza, umthamo we-NO2 wokushaja wanda kakhulu uma kuqhathaniswa neqembu le-vinyl ku-4-NS ngenxa yokudluliselwa kwe-electron ku-interface ye-Ru-Ni, okubonisa ukusebenza okuqondile kwe-NO bond eqenjini le-nitro.
I-In situ FT-IR yenzelwe ukuqapha inqubo ye-catalytic ye-4-NS hydrogenation reaction kumasampuli e-catalyst (Fig. 6).Nge-catalyst yokuqala ye-nickel (Fig. 6a), ukwehla okuncane kuphela kwe-nitro (1520 kanye ne-1351 cm-1) namabhendi e-C=C (1595 cm-1) kwabonwa lapho kudlula i-H2 imizuzu engu-12, okuyinto kubonisa ukuthi − I-activation NO2 kanye ne-C=C ibuthakathaka.Ebukhoneni be-monometallic Ru (Fig. 6b), ibhendi ν(C=C) (ku-1591 cm–1) incipha ngokushesha phakathi kwamaminithi angu-0–12, kuyilapho amabhendi u-νs(NO2) kanye ne-νas(NO2) encishiswa kakhulu. .Kancane Lokhu kukhombisa ukwenziwa kusebenze okukhethekile kweqembu le-vinyl le-hydrogenation, okuholela ekwakhekeni kwe-4-nitroethylbenzene (4-NE).Esimweni se-0.4 wt.I-% RuNi (SAA) (Fig. 6c), ibhendi ye-νs(NO2) (1347 cm–1) ishabalala ngokushesha ngokutheleka kwe-hydrogen, ehambisana nokubola kancane kancane kwe-ν(N=O ) ;ibhendi entsha egxile ku-1629 cm-1 nayo yabonwa, okubangelwa ukudlidliza kwe-NH.Ngaphezu kwalokho, ibhendi ye-ν(C=C) (1596 cm–1) ibonisa kuphela ukwehla kancane ngemva kwemizuzu eyi-12.Lolu shintsho oluguquguqukayo luqinisekisa i-polarization kanye ne-hydrogenation ye -NO2 kuya -NH2 ngo-0.4 wt% RuNi (SAA) ngokusekelwe ku-chemoselectivity eyingqayizivele ku-4-aminostyrene.Ngesampula ye-2 wt.% RuNi (Fig. 6d), ngaphezu kokuvela kwebhendi entsha engu-1628 cm–1 okuthiwa i-δ(NH), ibhendi ye-ν(C=C) iyancipha kakhulu futhi inyamalale ngebhendi ekhulayo yeqembu le-nitro (1514 futhi 1348 cm–1).Lokhu kubonisa ukuthi i-C = C kanye -NO2 isebenze ngokuphumelelayo ngenxa yokuba khona kwezikhungo ze-Ru-Ru ne-Ru-Ni interfacial, ngokulandelana, okuhambisana nokwakhiwa kwe-4-NE ne-4-AE ku-2 wt.% I-RuNi catalyst.
I-spectra ye-FT-IR ye-4-NS hydrogenation phambi kwe-monometallic Ni, b monometallic Ru, c 0.4 wt% RuNi SAA, kanye ne-d 2 wt% i-RuNi ekugelezeni kwe-H2 ku-1700-1240 cm- Ibanga 1 laqoshwa njengo igesi yokusabela ngemva kwemizuzu engu-0, 3, 6, 9 neyi-12, ngokulandelana.“au” kusho amayunithi angenasizathu.Ukusatshalaliswa kwamandla okungenzeka kanye nezakhiwo ezihambisanayo ezilungiselelwe ze-C=C hydrogenation kanye NO-scission ku-4-NS endaweni ye-e Ni(111) ne-f RuNi SAA(111).Ru – violet, Ni – green, C – orange, O – red, N – blue, H – white.“izikhangiso”, “IS”, “TS”, kanye ne-“FS” zimelela isimo sesikhangiso, isimo sokuqala, isimo soshintsho, kanye nesimo sokugcina ngokulandelana.
Izindlela ezingaba khona zokuguqulwa kwe-4-NS ku-Ni(111) kanye ne-RuNi SAA(111), okuhlanganisa i-C=C hydrogenation kanye ne-NO cleavage yebhondi, iphenywe ngezibalo ze-DFT ukuze kuqhutshekwe nokucacisa indima ebalulekile ye-4-NS.Izigaba ze-interface ye-Ru-Ni zokukhiqiza okuhlosiwe kwe-4-AS.Ku-Ni(111) surface (Fig. 6e), izithiyo zamandla ze-NO scission kanye ne-hydrogenation yamaqembu e-vinyl esigabeni sokuqala yi-0.74 kanye ne-0.72 eV, ngokulandelana, okubonisa ukuthi i-chemoselective hydrogenation yamaqembu e-nitro ku-4-HC engathandeki.indawo ye-nickel ye-monometallic.Ngokuphambene nalokho, umgoqo wamandla we-NO dissociation yi-0.46 eV kuphela ephakeme kune-RuNi SAA (111), ephansi kakhulu kune-C = C bond hydrogenation (0.76 eV) (Fig. 6f).Lokhu kuqinisekisa ngokungananazi ukuthi izikhungo ze-Ru-Ni interfacial zehlisa ngempumelelo umgoqo wamandla we-NO scission emaqenjini e-nitro, okuholela ekunciphiseni okukhethwa kukho kwe-thermodynamically kwamaqembu e-nitro uma kuqhathaniswa namaqembu e-C=C endaweni ye-RuNi surfactant, evumelana nemiphumela yokuhlola.
Indlela yokusabela kanye namajika wamandla abaliwe we-4-NS hydrogenation ku-RuNi SAA kwaphenywa ngokusekelwe ezibalweni ze-DFT (Fig. 7), futhi ukumiswa kwe-adsorption enemininingwane yezinyathelo eziyinhloko kuboniswa ku-Supplementary Fig. 41. Ukwandisa uhlelo lokubala, izithiyo ezikhiqiza amandla zama-molecule amanzi azifakwanga ekubalweni.amamodeli amapuleti9,17.Njengoba kuboniswe emkhiwaneni.7, ama-molecule e-4-NS aqala ukumuncwa ngokuhambisana ku-surfactant ye-RuNi, futhi ama-athomu amabili ama-O eqenjini le-nitro aboshelwe ezikhungweni ze-Ru-Ni interfacial (S0; isinyathelo I).Kamuva, isibopho se-NO esixhunywe kusayithi le-Ru siphukile, esihambisana nokwakhiwa kwe-nitroso intermediate (C8H7NO *) endaweni ye-interface ye-Ru-Ni kanye ne-O * endaweni engenalutho ye-Ni (S0 → S1 nge-TS1; amandla isithiyo: 0.46 eV, isinyathelo sesibili ).I-O* radicals yenziwa i-hydrogen ngama-athomu e-H asebenzayo ukuze akhe ama-molecule e-H2O ane-exotherm engu-0.99 eV (S1 → S2).Izithiyo zamandla ze-hydrogenation ye-C8H7NO* emaphakathi (Izibalo Ezingeziwe 42 kanye no-43) zibonisa ukuthi ama-athomu angu-H asebenzayo avela ezindaweni ezingenalutho ze-Ru-Ni ahlasela ngokukhethekile ama-athomu angu-O ngaphezu kwama-athomu angu-N, okuholela ku-C8H7NOH* (S2 → S4; isithiyo samandla TS2: 0.84 eV, isinyathelo III).Ama-athomu angu-N ku-C8H7NOH* abe esefakwa i-hydrogen ukuze akhe i-C8H7NHOH* ngemva kokuwela umgoqo we-1.03 eV (S4→S6; isinyathelo IV), okuyisinyathelo esichazayo sakho konke ukusabela.Okulandelayo, ibhondi ye-N–OH ku-C8H7NHOH* yaphulwa kusixhumi esibonakalayo se-Ru-Ni (S6 → S7; umgoqo wamandla: 0.59 eV; isigaba V), okwathi ngemva kwalokho i-OH* yafakwa i-hydrogen yaba ngu-HO (S7 → S8; exotherm: 0.31 eV ) Ngemva kwalokho, ama-athomu angu-N wezindawo ezingenalutho ze-Ru-Ni ku-C8H7NH* aphinde afakwa i-hydrogen ukuze akhe i-C8H7NH2* (4-AS) enomkhawulo wamandla ongu-0.69 eV (S8 → S10; isinyathelo VI).Ekugcineni, ama-molecule e-4-AS kanye ne-HO akhishwa ebusweni be-RuNi-PAA, futhi i-catalyst yabuyela esimweni sayo sokuqala (isinyathelo VII).Lesi sakhiwo esiyingqayizivele esihlanganisa ubuso phakathi kwama-athomu e-Ru eyodwa kanye nama-Ni substrates, ahambisana nomphumela we-synergistic we-doping host ku-RuNi SAA, kubangela umsebenzi ovelele kanye ne-chemoselectivity ye-4-NS hydrogenation.
Ilayisi.4. Umdwebo we-Schematic wendlela yokusabela kwe-hydrogenation ye-NS kuya ku-4-AS endaweni ye-RuNi PAA.Ru – violet, Ni – green, C – orange, O – red, N – blue, H – white.Isethi ibonisa ukusatshalaliswa kwamandla angaba khona e-4-NS hydrogenation endaweni ye-RuNi SAA(111), abalwe ngesisekelo se-DFT.I-“S0″ imele isimo sokuqala, futhi i-“S1-S10” imele uchungechunge lwezifunda ze-adsorption.I-“TS” imele isimo soguquko.Izinombolo ezikubakaki zimelela izithiyo zamandla zezinyathelo eziyinhloko, futhi izinombolo ezisele zimelela amandla e-adsorption wabaphakathi abahambisanayo.
Ngakho, ama-catalysts e-RuNi SAA atholwe kusetshenziswa ukusabela kwe-electrosubstitution phakathi kwe-RuCl3 ne-Ni NPs etholwe kuma-precursors e-LDH.Uma kuqhathaniswa ne-monometallic Ru, i-Ni ebikiwe ngaphambilini, i-RuNi SAA eyaba umphumela yabonisa ukusebenza kahle okuphezulu kwe-catalytic ye-4-NS chemoselective hydrogenation (isivuno se-4-AS: > 99%; inani le-TOF: 4293 h-1).Izinhlamvu ezihlanganisiwe ezihlanganisa i-AC-HAADF-STEM, in situ CO-DRIFTS, kanye ne-XAFS iqinisekise ukuthi ama-athomu e-Ru ayenganyakazi kuma-Ni NPs ezingeni le-athomu eyodwa ngamabhondi e-Ru-Ni, ayehambisana nokudluliswa kwe-electron kusuka ku-Ni kuya ku-Ru.Ku-situ XAFS, ukuhlolwa kwe-FT-IR, kanye nezibalo ze-DFT zibonise ukuthi isayithi lokusebenzelana le-Ru-Ni lisebenza njengendawo esebenzayo yangaphakathi yokwenza kusebenze okukhethekile kwe-NO bond eqenjini le-nitro;ukusebenzisana phakathi kwe-Ru kanye nezingosi ezingomakhelwane ze-Ni kusiza ukusebenza okuphakathi kanye ne-hydrogenation, ngaleyo ndlela kuthuthukisa kakhulu ukusebenza kahle kwe-catalytic.Lo msebenzi unikeza ukuqonda ngobudlelwano phakathi kwezindawo ezisebenza kabili ezisebenzayo kanye nokuziphatha kwe-catalytic kwe-SAA ezingeni le-athomu, okuvula indlela yokuklama okunengqondo kwamanye ama-catalyst anezindlela ezimbili ngokukhetha okufunayo.
Ama-reagents okuhlaziya asetshenziswe ekuhloleni athengwe ku-Sigma Aldrich: Al2(SO4)3 18H2O, sodium tartrate, CO(NH2)2, NH4NO3, Ni(NO3)2 6H2O, RuCl3, ethanol, 4-nitrostyrene (4- NS) , 4-aminostyrene, 4-nitroethylbenzene, 4-aminoethylbenzene kanye ne-nitrostyrene.Amanzi ahlanzekile asetshenziswa kukho konke ukuhlola.
Ama-Hierarchical NiAl LDHs ahlanganiswa njengama-precursors ngokukhula endaweni.Okokuqala, i-urea (3.36 g), i-Al2 (SO4) 3 · 18H2O (9.33 g) ne-sodium tartrate (0.32 g) yachithwa emanzini angenalutho (140 ml).Isixazululo esiwumphumela sidluliselwe ku-autoclave ye-Teflon-coated futhi sishise ku-170 ° C amahora angu-3.I-precipitate ebangelwayo yagezwa ngamanzi a-distilled futhi yomiswa kahle, ngemva kwalokho i-calcined ku-500 ° C (2 ° C min-1; 4 h) ukuze ithole i-amorphous Al2O3.Khona-ke i-Al2O3 (0.2 g), i-Ni(NO3)2 6H2O (5.8 g) kanye ne-NH4NO3 (9.6 g) yahlakazwa emanzini ahlanzekile (200 ml) futhi i-pH yalungiswa ku-~6.5 ngokungeza i-1 mol l -1 amanzi ammonia..Ukumiswa kudluliselwe eflaskini futhi kwagcinwa ku-90°C amahora angu-48 ukuze kutholwe i-NiAl-LDH.Khona-ke i-NiAl-LDH powder (0.3 g) yehliswa emfudlaneni we-H2/N2 (10/90, v/v; 35 ml min–1) ngo-500°C amahora angu-4 (izinga lokushisa: 2°C min -1 ).Ukulungiswa kwamasampula e-monometallic nickel (Ni/Al2O3) afakwe ku-amorphous Al2O3.Amasampula e-bimetallic afakwe e-RuNi ahlanganiswa ngendlela ye-electrodisplacement.Ngokujwayelekile, isampula elisha le-Ni/Al2O3 (0.2 g) lahlakazwa ku-30 ​​ml wamanzi ahlanzekile, bese isixazululo se-RuCl3 (0.07 mmol l-1) sengezwa kancane futhi sanyakaziswa ngamandla imizuzu engama-60 ngaphansi kokuvikelwa komkhathi we-N2. .Imvula ewumphumela yayiyi-centrifuged, igezwe ngamanzi ahlanzekile, futhi yomiswa kuhhavini we-vacuum ku-50 ° C amahora angu-24, ithola isampula equkethe i-0.1% RuNi.Ngaphambi kokuhlolwa kwe-catalytic, amasampuli asanda kuhlanganiswa ancishiswa ekuqaleni ekugelezeni kwe-H2/N2 (10/90, v/v) ku-300°C (izinga lokushisa: 2°C min–1) ihora elingu-1, bese lishiselwa ngaphakathi. I-N2 Ipholile ekamelweni lokushisa.Ukuze uthole ireferensi: amasampula anokuqukethwe kwe-Ru/Al2O3 okungu-0.4% no-2% ngesisindo, nokuqukethwe kwe-Ru yangempela okungu-0.36% ngesisindo kanye no-2.3% ngobuningi, alungiselwe imvula ngemvula futhi ashiselwe ku-300 °C (ukusetshenziswa kwe-H2/ N2 : 10/90, v/v, izinga lokushisa: 2 °C min–1) amahora angu-3.
Ukuhlolwa kwe-X-ray diffraction (XRD) kwenziwa ku-Bruker DAVINCI D8 ADVANCE diffractometer enomthombo wemisebe we-Cu Kα (40 kV kanye no-40 mA).I-Shimadzu ICPS-7500 Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) yasetshenziswa ukuze kutholwe inala yangempela yezinto kumasampuli ahlukahlukene.Izithombe ze-electron microscopy (SEM) ezithwetshulwa kusetshenziswa isibonakhulu se-electron ye-Zeiss Supra 55.Ukuhlolwa kwe-adsorption-desorption ye-N2 kwenziwa kudivayisi ye-Micromeritics ASAP 2020 futhi indawo ethile yabalwa kusetshenziswa indlela ye-Brunauer-Emmett-Teller (BET) yamaphoyinti amaningi.Izici ze-Transmission electron microscopy (TEM) zenziwe ngesibonakhulu se-JEOL JEM-2010 yokudlulisa isinqumo esiphezulu.I-Engle Aberration Elungile Yokudlulisa Iskena I-Electron Microscope Dark Field (AC-HAADF) – STEM ene-FEI Titan Cube Themis G2 300 ene-spherical aberration corrector kanye nesistimu ye-Energy Dispersive X-ray Spectroscopy (EDS) kanye ne-JEOL JEM-ARM200F izilinganiso) nezikali zemephu ze-EDS .Isakhiwo esihle i-X-ray absorption spectroscopy (XAFS) ku-situ K-edge ye-Ru ne-Ni K-edge ikalwe eziteshini 1W1B kanye ne-1W2B ye-Beijing Synchrotron Radiation Facility (BSRF) ye-Institute of High Energy Physics (IHEP), China .I-Academy of Sciences (KAN).Ukuhlolwa kwe-pulsed CO chemisorption kanye ne-thermal-programmed hydrogen desorption (H2-TPD) kwenziwa ethuluzini le-Micromeritics Autochem II 2920 kusetshenziswa umtshina wokushisa oshisayo (TCD).Ukuhlolwa kwe-in situ DRIFTS kanye ne-FT-IR kwenziwa ku-spectrometer ye-infrared ye-Bruker TENSOR II efakwe iseli yokusabela eguquliwe e-situ kanye nomtshina we-MCT ozwela kakhulu.Izindlela zezinhlamvu ezinemininingwane zichazwe olwazini Olwengeziwe.
Okokuqala, i-substrate (4-NS, 1 mmol), i-solvent (ethanol, 8 ml) kanye ne-catalyst (0.02 g) yengezwe ngokucophelela ku-autoclave yensimbi engagqwali engu-25 ml.I-reactor yabe isihlanzwa ngokuphelele nge-2.0 MPa (>99.999%) i-hydrogen izikhathi ezi-5, yabe isicindezelwa futhi yavalwa ku-1.0 MPa nge-H2.Ukusabela kwenziwa ku-60 ° C ngesivinini esishukumisayo esingaguquki esingu-700 rpm.Ngemva kokusabela, imikhiqizo ewumphumela ikhonjwe yi-GC-MS futhi yahlaziywa ngokomthamo kusetshenziswa isistimu ye-gas chromatography ye-Shimadzu GC-2014C efakwe ikholomu ye-capillary ye-GSBP-INOWAX (30 m×0.25 mm×0.25 mm) nomtshina we-FID.Ukuguqulwa kwe-4-nitrostyrene nokukhetha komkhiqizo kunqunywe kanje:
Amanani we-turnover frequency (TOF) abalwe njenge-mol 4-NS eguqulelwe kumasayithi ensimbi ye-mol ngehora (mol4-NS mol-1 h-1) ngokusekelwe ekuguquleni okuphansi kwe-4-NS (~15%).Ngokuqondene nenani lama-ru node, ama-interface node we-Ru-Ni kanye nenani eliphelele lama-athomu ensimbi angaphezulu.Ukuze kuhlolwe ukuphinda kusetshenziswe kabusha, i-catalyst yaqoqwa nge-centrifugation ngemva kokusabela, yawashwa kathathu nge-ethanol, yabe isiphinde yethulwa ku-autoclave ngomjikelezo olandelayo we-catalytic.
Zonke izibalo ze-density functional theory (DFT) zenziwe kusetshenziswa iphakheji ye-Vienna ab initio simulation (VASP 5.4.1).Umsebenzi we-Generalized Gradient Approximation (GGA) PBE usetshenziselwa ukuchaza ukushintshaniswa kwama-electron nezimo zokuhlobana.Indlela ye-Projector Augmented Wave (PAW) isetshenziselwa ukuchaza ukusebenzisana phakathi kwama-nuclei e-athomu nama-electron.Indlela ye-Grimm DFT-D3 ichaza umthelela wokusebenzelana kwe-van der Waals phakathi kwe-substrate nesixhumi esibonakalayo.Ukubalwa Kwezithiyo Zamandla Ngokukhuphuka Amabhendi Elastic Nge-Image Boost (CI-NEB) kanye Nezindlela ze-Dimer.Ukuhlaziywa kwemvamisa ye-oscillations kwenziwa, okuqinisekisa ukuba khona kwemvamisa eyodwa kuphela ecatshangwayo esimweni ngasinye soguquko (Izibalo Ezingeziwe 44-51).Izibalo ezinemininingwane eyengeziwe zichazwe olwazini olwengeziwe.
Idatha eyinhloko esekela iziqephu kulesi sihloko inikezwe kumafayela edatha yomthombo.Eminye imininingwane ehlobene nalolu cwaningo iyatholakala kubabhali abafanele uma kunesicelo esifanele.Lesi sihloko sinikeza idatha yoqobo.
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