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Moralo le nts'etsopele ea li-catalysts tsa ts'ebetso e phahameng li fumane tlhokomelo e kholo mekhoeng e khethiloeng ea hydrogenation empa e ntse e le phephetso e kholo.Mona re tlaleha monatomic RuNi motsoako (SAA) eo ho eona motho ka mong Ru liathomo immobilized holim 'a Ni nanoparticles ka Ru-Ni coordination, e leng e tsamaea le elektrone fetisa ho tloha subsurface Ni ho Ru.Ho ea ka tsebo ea rona, catalyst e ntle ka ho fetisisa 0.4% RuNi SAA ka nako e le 'ngoe e bontšitse mosebetsi o phahameng (tekanyo ea TOF: 4293 h-1) le chemoselectivity bakeng sa khetho ea hydrogenation ea 4-nitrostyrene ho 4-aminostyrene (ka lihlahisoa:> 99%), boemo bo phahameng ka ho fetisisa ka ha e bapisoa le li-catalyst tse tsebahalang.Liteko tsa in situ le lipalo tsa theoretical li bonts'a hore libaka tsa marang-rang tsa Ru-Ni, e le libaka tse sebetsang ka hare, li khothalletsa ho robeha ka mokhoa o khethehileng oa NO bonds ka mokoallo o fokolang oa matla a 0.28 eV.Ho phaella moo, synergistic Ru-Ni catalysis e rata ho thehoa ha li-intermediates (C8H7NO * le C8H7NOH *) le ho potlakisa mohato oa ho khetholla sekhahla (hydrogenation ea C8H7NOH *).
Li-amine tse nkhang hamonate tse sebetsang hantle, meaho ea bohlokoa ea lik'hemik'hale tse ntle, li na le ts'ebeliso ea bohlokoa ea indasteri tlhahisong ea meriana, lik'hemik'hale tsa temo, li-pigments le li-polymers1,2,3.The catalytic hydrogenation ea lik'hemik'hale tsa nitroaromatic tse fumanehang habonolo holim'a li-catalyst tse sa tšoaneng li hohetse tlhokomelo e kholo e le mokhoa oa ho boloka tikoloho le o ka sebelisoang hape bakeng sa motsoako oa li-amine tse nang le bohlokoa bo eketsehileng4,5,6,7.Leha ho le joalo, ho fokotseha ha chemoselective ea lihlopha tsa -NO2 ha ho ntse ho boloka lihlopha tse ling tse fokolang tse kang alkenes, alkynes, halogens, kapa ketone ke mosebetsi o lakatsehang haholo empa ho e-na le phephetso8,9,10,11.Ka hona, tšebeliso e utloahalang ea li-catalysts tse fapaneng bakeng sa ho fokotseha ho itseng ha lihlopha tsa -NO2 ntle le ho ama litlamo tse ling tse fokolang ke tse lakatsehang haholo12,13,14.Li-catalyst tse ngata tse se nang tšepe li 'nile tsa batlisisoa ho etsa hore ho be le hydrogenation ea nitroarenes, empa maemo a thata a karabelo a thibela tšebeliso ea bona e pharaletseng15,16.Leha li-catalyst tsa tšepe tse ntle (tse kang Ru17, Pt18, 19, 20 kapa Pd21, 22, 23) li sebetsa tlas'a maemo a bonolo a karabelo, hangata li na le litšenyehelo tse phahameng, khetho e tlase, le tšebeliso e tlase ea athomo.Ka hona, ho fumana li-catalyst tse sebetsang haholo le tse khethollang lik'hemik'hale ka moralo o utloahalang le ho lokisa sebopeho se setle e ntse e le phephetso e kholo24,25,26.
Li-catalyst tsa Monatomic Alloy (SAA) li na le ts'ebetso e phahameng ka ho fetesisa ea tšepe, sebopeho se ikhethileng sa jiometri le elektroniki, li fana ka libaka tse ikhethang tse sebetsang, 'me li fana ka ts'ebetso e ikhethang ka ho tlola sebopeho sa linear scaling27,28,29,30,31.Liathomo tse nang le metsi a le mong le liathomo tsa tšepe tse amohelang SAA li ka sebetsa e le libaka tse peli tse sebetsang, tse nolofatsang ts'ebetso ea li-substrates tse ngata kapa tsa lumella mehato e fapaneng ea motheo ea ho arabela libakeng tse fapaneng32,33,34.Ho phaella moo, litloaelano tsa heterometallic pakeng tsa liathomo tsa tšepe tse sa hloekang tse ka thōko le lisebelisoa tsa tšepe li ka lebisa liphellong tsa idiosyncratic synergistic, le hoja kutloisiso ea liphello tse joalo tsa synergistic pakeng tsa lihlopha tse peli tsa libaka tsa tšepe boemong ba athomo e ntse e le tsekisano35,36,37,38.Bakeng sa hydrogenation ea nitroarenes e sebetsang, meaho ea elektronike le ea geometri ea libaka tse sebetsang li tlameha ho etsoa ka tsela e tla potlakisa ts'ebetso ea lihlopha tsa nitro feela.Ha e le molao, lihlopha tsa nitro tse haelloang ke elektronike li adsorbed haholo libakeng tsa nucleophilic tsa catalyst surface, ha tseleng e latelang ea hydrogenation, cooperative catalysis ea libaka tsa boahelani tse sebetsang li tla phetha karolo ea bohlokoa ho laola reactivity le chemoselectivity4,25.Sena se ile sa re susumelletsa ho hlahloba li-catalysts tsa SAA e le mokhethoa ea tšepisang bakeng sa ho ntlafatsa katleho ea chemoselective hydrogenation ea metsoako ea nitroaromatic, hammoho le ho tsoela pele ho hlakisa kamano pakeng tsa sebopeho sa sebaka se sebetsang le ts'ebetso ea atomic scale catalytic.
Mona, li-catalysts tse thehiloeng ho li-alloys tsa RuNi tsa monatomic li ne li lokiselitsoe ho latela mokhoa oa maiketsetso oa mekhahlelo e 'meli, ho kenyelletsa le phetoho ea sebopeho-topological ea layered double hydroxide (LDH) e lateloang ke phekolo ea electro-displacement.RuNi SAA e bonts'a katleho e ikhethang ea catalytic (> 99% chai) bakeng sa chemoselective hydrogenation ea 4-nitrostyrene ho 4-aminostyrene e nang le turnover frequency (TOF) ea ho fihla ho ~ 4300 mol-mol Ru-1 h-1, e leng eona e phahameng ka ho fetisisa. boemo har'a li-catalyst tse fapaneng tse ngolisitsoeng tlas'a maemo a ts'oanang a karabelo.Electron microscopy le spectroscopic characterization li bontšitse hore liathomo tsa Ru tse arohaneng li qhalakantsoeng holim'a Ni nanoparticles (~ 8 nm), ho etsa tšebelisano e tsitsitseng ea Ru-Ni, e hlahisang libaka tse mpe tsa Ru (Ruδ-) ka lebaka la ho fetisoa ha elektronike ho tloha ka tlas'a lefatše Ni ho Ru. .In situ FT-IR, lithuto tsa XAFS le lipalo tsa density functional theory (DFT) li netefalitse hore libaka tsa sebopeho sa Ru-Ni joalo ka libaka tse sebetsang ka hare li thusa nitro.Activated adsorption (0.46 eV) e fapane le ea monometallic nickel catalyst.(0.74 eV).Ho phaella moo, ho arohana ha hydrogen ho etsahala libakeng tsa boahelani tsa Ni, ho lateloa ke hydrogenation ea li-intermediates (C8H7NO * le C8H7NOH *) libakeng tsa Ruδ.Tšusumetso ea synergistic ea ts'ehetso ea doping ho "ruNi SAA catalyst" e fella ka ts'ebetso e ikhethang ea nitroarenes hydrogenation le selectivity, e ka fetisetsoang ho li-catalyst tse ling tse sa tloaelehang tsa tšepe tse sebelisoang molemong oa karabelo e hlokolosi.
Ho ipapisitsoe le phetoho ea sebopeho sa topology ea li-precursors tsa layered double hydroxide (LDH), re lokisitse monometallic Ni e kentsoeng ho li-amorphous Al2O3 substrates.Ka mor'a moo, sete ea RuNi / Al2O3 bimetallic disampole tse fapaneng Ru content (0.1-2 wt %) ne ka nepo synthesized ke electrodisplacement ho beha Ru liathomo holim 'a Ni nanoparticles (NPs) (Fig. 1a).Litekanyo tsa plasma atomic emission spectrometry (ICP-AES) tse kopantsoeng ka mokhoa o hlakileng li fane ka sebopeho sa mantlha sa Ru le Ni lisampole tsena (Letlapa la Tlatsetso la 1), le haufi le theoretical feedstock loading.Litšoantšo tsa SEM (Setšoantšo sa Tlatsetso 1) le liphetho tsa BET (Lipalo tsa Tlatsetso 2-9 le Letlapa la Tlatsetso la 1) li bonts'a ka ho hlaka hore sebopeho sa morphological le sebaka se ikhethileng sa lisampole tsa RuNi/Al2O3 ha se fetohe liphetoho tse hlakileng nakong ea kalafo ea electrochemical.- mokhoa oa ho falla.Sebopeho sa X-ray (setšoantšo sa 1b) se bontša letoto la litšoantšiso tsa sebopeho ho 2θ 44.3 °, 51.6 °, le 76.1 °, e bontšang mekhahlelo (111), (200), le (220) ea Ni (JCPDS 004-0850). ).Haholo-holo, lisampole tsa RuNi ha li bonts'e litšoantšo tsa Ru ea tšepe kapa e nang le oxidized, e leng se bontšang ho hasana ho hoholo ha mefuta ea Ru.Transmission electron microscopy (TEM) litekanyo tsa monometallic Ni le RuNi disampole (Fig. 1c1-c8) bontša hore nickel nanoparticles hantle qhalakantsoeng le immobilized ka amorphous Al2O3 tshehetso e nang le likaroloana boholo bo tšoanang (7.7-8.3 nm).Litšoantšo tsa HRTEM (Litšoantšo tsa 1d1-d8) li bonts'a nako e lekanang ea lattice e ka bang 0.203 nm ka lisampole tsa Ni le RuNi, tse lumellanang le lifofane tsa Ni (111), leha ho le joalo, likhahla tsa lattice tsa likaroloana tsa Ru ha li eo.Sena se bontša hore liathomo tsa Ru li hasane haholo holim'a sampuli mme ha li ame nako ea Ni lattice.Ho sa le joalo, 2 wt% Ru / Al2O3 e ne e entsoe ka mokhoa oa ho beha-deposition e le taolo, moo lihlopha tsa Ru li neng li ajoa ka mokhoa o ts'oanang holim'a substrate ea Al2O3 (Supplementary Figs. 10-12).
a Scheme ea mokhoa oa ho kopanya bakeng sa lisampole tsa RuNi/Al2O3, b mekhoa ea ho fapana ha X-ray ea Ni/Al2O3 le disampole tse fapaneng tsa RuNi/Al2O3.c1−c8 TEM le d1−d8 HRTEM litšoantšo tsa grating tse nang le kabo ea boholo ba likaroloana tsa monometallic Ni, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0, 8% wt., 1 wt.Setšoantšo se metsero.% le 2 wt.% RuNi.“au” e bolela diyuniti tse sa tshwaneng.
Mosebetsi oa catalytic oa mehlala ea RuNi e ile ea ithutoa ke chemoselective hydrogenation ea 4-nitrostyrene (4-NS) ho 4-aminostyrene (4-AS).Phetoho ea 4-NS ho substrate e hloekileng ea Al2O3 e ne e le 0.6% feela ka mor'a lihora tsa 3 (Supplementary Table 2), e bontšang phello e nyenyane ea catalytic ea Al2O3.Joalokaha ho bontšitsoe feiga.2a, mokelikeli oa nickel oa pele o bontšitse ts'ebetso e tlase haholo ea ts'ebetso e nang le phetoho ea 4-NS ea 7.1% ka mor'a lihora tsa 3, ha phetoho ea 100% e ka finyelloa boteng ba monometallic Ru catalyst tlas'a maemo a tšoanang.Li-catalysts tsohle tsa RuNi li bontšitse ts'ebetso e eketsehileng ea hydrogenation (phetoho: ~ 100%, 3 h) ha e bapisoa le mehlala ea monometallic, 'me sekhahla sa karabelo se ne se amana hantle le litaba tsa Ru.Sena se bolela hore likaroloana tsa Ru li phetha karolo ea bohlokoa ts'ebetsong ea hydrogenation.Hoa thahasellisa hore khetho ea sehlahisoa (setšoantšo sa 2b) se fapana haholo ho itšetlehile ka se susumetsang.Bakeng sa sesebelisoa sa nickel se sa sebetseng hantle, sehlahisoa se seholo e ne e le 4-nitroethylbenzene (4-NE) (khetho: 83.6%) le khetho ea 4-AC e ne e le 11.3%.Tabeng ea monometallic Ru, C = C bond ho 4-NS e ka hlaseloa habonolo ke hydrogenation ho feta -NO2, e lebisang ho thehoeng ha 4-nitroethylbenzene (4-NE) kapa 4-aminoethyl benzene (4-AE);khetho ea 4-AC e ne e le 15.7% feela.Hoa makatsa hore ebe li-catalysts tsa RuNi tse nang le boitsebiso bo fokolang ba Ru (0.1-0.4 wt%) li bontšitse khetho e babatsehang (> 99%) ho 4-aminostyrene (4-AS), e bontšang hore ke NO2 eseng vinyl, ke chemoselective e ikhethang.Ha litaba tsa Ru li feta 0.6 wt.%, khetho ea 4-AS e fokotsehile haholo ka ho eketseha ha Ru, ha khetho ea 4-AE e ntse e eketseha ho e-na le hoo.Bakeng sa mokelikeli o nang le 2 wt% RuNi, lihlopha tsa nitro le vinyl li ne li e-na le hydrogenated haholo ka khetho e phahameng ho 4-AE ea 98%.Ho ithuta phello ea boemo ba ho hasana ha Ru ka karabelo ea catalytic, 0.4 wt% Ru/Al2O3 disampole li ile tsa lokisoa (Supplementary Figures 10, 13 le 14) moo likaroloana tsa Ru li neng li qhalakanngoa haholo e le liathomo ka bomong tse lateloang ke lihlopha tse 'maloa tsa Ru.(quasi-atomic Ru).Ts'ebetso ea catalytic (Supplementary Table 2) e bontša hore 0.4 wt% Ru / Al2O3 e ntlafatsa khetho ea 4-AS (67.5%) ha e bapisoa le sampuli ea 2 wt% Ru / Al2O3, empa mosebetsi o tlaase haholo (phetoho: 12.9).%;Lihora tse 3).Ho itšetlehile ka palo eohle ea libaka tsa tšepe tse holim'a metsi tse khethiloeng ke CO pulsed chemisorption litekanyo, lebelo la phetoho (TOFmetal) ea RuNi catalyst e ile ea fumanoa ka tlaase ho 4-NS phetoho (Supplementary Fig. 15), e ileng ea bontša mokhoa oa pele oa ho eketseha. 'me joale e fokotsehe ka keketseho e ntseng e eketseha ea Ru loading (Supplementary Fig. 16).Sena se fana ka maikutlo a hore ha se libaka tsohle tsa tšepe tse holim'a metsi tse sebetsang e le libaka tsa tlhaho tse sebetsang bakeng sa li-catalysts tsa RuNi.Ho phaella moo, TOF ea RuNi catalyst e ne e baloa ho tloha libakeng tsa Ru ho tsoela pele ho senola mosebetsi oa eona oa tlhaho oa ho kenya letsoho (setšoantšo sa 2c).Ha litaba tsa Ru li ntse li eketseha ho tloha ho 0,1 wt.% ho isa ho 0.4 wt.% Li-catalysts tsa RuNi li bontšitse hoo e batlang e le litekanyetso tsa TOF (4271-4293 h-1), tse bontšang ho fumaneha ha likaroloana tsa Ru ka ho hasana ha athomo (mohlomong ka ho thehoa ha RuNi SAA).) mme e sebetsa joalo ka sebaka sa mantlha se sebetsang.Leha ho le joalo, ka keketseho e 'ngoe ea ho laela Ru (ka hare ho 0.6-2 wt%), boleng ba TOF bo fokotseha haholo, e leng se bontšang phetoho ea sebopeho sa kahare sa setsi se sebetsang (ho tloha ho qhalakanngoa ha athomo ho ea ho Ru nanoclusters).Ho phaella moo, ho tsebo ea rona, TOF ea 0.4 wt% RuNi (SAA) catalyst e boemong bo phahameng ka ho fetisisa har'a li-catalyst tsa tšepe tse tlalehiloeng pele tlas'a maemo a ts'oanang a ts'ebetso (Supplementary Table 3), e bontšang hape hore li-alloys tsa RuNi tsa monoatomic li fana ka thepa e babatsehang ea catalytic.sebono.Setšoantšo sa Tlatsetso 17 se bonts'a ts'ebetso ea ts'ebetso ea 0.4 wt% RuNi (SAA) ka likhatello tse fapaneng le mocheso oa H2, moo khatello ea H2 ea 1 MPa le mocheso oa karabelo oa 60 ° C o sebelisitsoeng e le litekanyetso tse nepahetseng tsa ho itšoara.sampole e nang le RuNi 0,4 wt.% (setšoantšo sa 2d), 'me ha ho na ho fokotseha ho hoholo ha mosebetsi le lihlahisoa ho ile ha hlokomeloa ho feta lipotoloho tse hlano tse latellanang.Litšoantšo tsa X-ray le TEM tsa 0.4 wt% RuNi catalyst e sebelisitsoeng ka mor'a lipotoloho tsa 5 (Supplementary Figures 18 le 19) ha e bontše liphetoho tse kholo mohahong oa kristale, e bontšang botsitso bo phahameng ba khetho ea hydrogenation e khethiloeng.Ho phaella moo, 0.4 wt% RuNi (SAA) catalyst e boetse e fana ka lihlahisoa tse babatsehang tsa amine bakeng sa chemoselective hydrogenation ea metsoako e meng ea nitroaromatic e nang le lihlopha tsa halogens, aldehydes, le hydroxyl (Supplementary Table 4), e bontšang hore e sebetsa hantle.
Phetoho ea Catalytic le b kabo ea lihlahisoa tsa 4-nitrostyrene hydrogenation ka pel'a monometallic Ni, Ru, le RuNi li-catalysts tse nang le litaba tse fapaneng tsa Ru (0.1-2 wt %), c ka har'a catalytic dynamic range, Turnover frequency (TOF) ho RuNi li-catalysts c ho itšetlehile ka Ru ka mole.d Teko ea monyetla oa ho sebelisoa hape ha 0.4 wt.% RuNi catalyst bakeng sa lipotoloho tse hlano tse latellanang tsa catalytic.ln (C0/C) e ipapisitse le nako ea karabelo ea hydrogenation ea e-nitrobenzene le f-styrene ka motsoako oa nitrobenzene le styrene (1:1).Maemo a ho itšoara: 1 mmol ea reagent, 8 ml solvent (ethanol), 0.02 g catalyst, 1 MPa H2, 60 ° C, lihora tse 3.Li-barbar tsa liphoso li hlalosoa e le ho kheloha ho tloaelehileng ha likopi tse tharo.
Ho tsoela pele ho etsa lipatlisiso ka phapang e kholo ea chemoselective, hydrogenation ea motsoako oa styrene le nitrobenzene (1: 1) e ile ea boela ea etsoa ka pel'a monometallic catalysts Ni, Ru, 0.4 wt% RuNi, le 2 wt% RuNi, ka ho latellana (Supplementary Fig. 20).Le hoja chemoselectivity ea likarabo tsa hydrogenation ea lihlopha tse sebetsang li lumellana, ka sebele ho na le phapang pakeng tsa khetho ea intramolecular le intermolecular hydrogenation ka lebaka la liphello tsa molecular allosteric.Joalokaha ho bontšitsoe feiga.2e,f, curve ln(C0/C) khahlano le nako ea karabelo e fana ka mola o otlolohileng ho tloha qalong, e bonts'a hore nitrobenzene le styrene ka bobeli ke tatellano ea pseudo-first order.Monometallic nickel catalysts e bonts'itse maemo a tlase haholo a hydrogenation rate bakeng sa bobeli p-nitrobenzene (0.03 h-1) le styrene (0.05 h-1).Haholo-holo, mosebetsi o khethehileng oa styrene hydrogenation (sekhahla se sa fetoheng: 0.89 h-1) se fihletsoe ho Ru monometallic catalyst, e leng holimo haholo ho ts'ebetso ea nitrobenzene hydrogenation (sekhahla sa kamehla: 0.18 h-1).Tabeng ea catalyst e nang le RuNi(SAA) 0.4 wt.% nitrobenzene hydrogenation e molemo ka matla ho feta styrene hydrogenation (tekanyo e tsitsitseng: 1.90 h-1 vs. 0.04 h-1), e bontšang khetho bakeng sa sehlopha sa -NO2.ho feta C hydrogenation = bond C. Bakeng sa mokelikeli o nang le 2 wt.% RuNi, tekanyo e sa fetoheng ea hydrogenation ea nitrobenzene (1.65 h-1) e fokotsehile ha e bapisoa le 0.4 wt.% RuNi (empa e ntse e phahame ho feta ea mono-metal catalyst), ha tekanyo ea hydrogenation ea styrene e eketseha haholo (tekanyo e tsitsitseng: 0,68).h−1).Sena se boetse se bontša hore ka phello ea synergistic pakeng tsa Ni le Ru, ts'ebetso ea catalytic le chemoselectivity ho ea -NO2 lihlopha li eketsehile haholo ha li bapisoa le RuNi SAA.
Ho bona hore na boemo ba ho qhalakana ha metsoako ea Ru le Ni ke bofe, ho ile ha etsoa mokhoa oa ho nka litšoantšo o sebelisang lesale le lefifi la electron microscopy e nang le aberration correction (AC-HAADF-STEM) le 'mapa oa lintho ka matla a li-dispersive spectroscopy (EDS).'Mapa oa motheo oa EMF oa sampuli o nang le 0,4 wt% RuNi content (setšoantšo sa 3a, b) se bontša hore Ru e arotsoe ka mokhoa o ts'oanang ka mokhoa o ts'oanang ho nanoparticles ea nickel, empa eseng ka substrate ea Al2O3, setšoantšo se lumellanang sa AC-HAADF-STEM (Fig. 3c) e bonts'a, Ho ka bonoa hore bokaholimo ba Ni NPs bo na le matheba a mangata a khanyang a boholo ba athomo ea liathomo tsa Ru (tse tšoailoeng ka metsu e putsoa), athe ha ho na lihlopha kapa li-nanoparticles tsa Ru.Setšoantšo sa 3d), ho bontša ho thehoa ha li-alloys tsa RuNi tsa monatomic.Bakeng sa mohlala o nang le RuNi 0,6 wt.% (setšoantšo sa 3e), liathomo tsa Ru e le 'ngoe le palo e nyenyane ea likaroloana tsa Ru li ile tsa hlokomeloa ho Ni NPs, e leng se bontšang ho bokellana ha liathomo tse nyenyane tsa Ru ka lebaka la mojaro o eketsehileng.Tabeng ea sampuli e nang le 2 wt% RuNi content, lihlopha tse ngata tse kholo tsa Ru ka Ni NPs li fumanoe setšoantšong sa HAADF-STEM (Fig. 3f) le 'mapa oa motheo oa EDS (Supplementary Fig. 21), e bontšang ho bokellana ho hoholo ha Ru. .
setšoantšo sa HAADF-STEM, b setšoantšo sa 'mapa sa EDS se lumellanang, c setšoantšo se phahameng sa AC-HAADF-STEM, d setšoantšo sa STEM se hōlisitsoeng le kabo e lumellanang ea matla a 0.4 wt% RuNi sampole.(e, f) AC–HAADF–STEM litšoantšo tsa lisampole tse nang le 0.6 wt.% RuNi le 2 wt.% RuNi, ka ho latellana.
Ha ho bapisoa le li-sampuli tsa Ni / Al2O3 le Ru / Al2O3, setšoantšo sa DRIFTS sa CO adsorption in situ se ile sa etsoa (setšoantšo sa 4a) ho tsoela pele ho ithuta lintlha tsa sebopeho sa mehlala e nang le 0.4 wt.%, 0.6 wt.% le 2 wt.% RuNi.Phatlalatso ea CO ho sampole ea Ru/Al2O3 e fana ka tlhoro e kholo ho 2060 cm-1 le tlhoro e 'ngoe e pharaletseng ho 1849 cm-1 e hlahisoang ke linear CO adsorption ho Ru le ho hokahanya liathomo tse peli tsa boahelani tsa Ru, ka ho latellana CO39,40.Bakeng sa mohlala oa monometallic Ni, tlhōrō e matla e bonoa feela ho 2057 cm-1, e hlahisoang ke linear CO41,42 sebakeng sa nickel.Bakeng sa sampuli ea RuNi, ho phaella tlhōrōng e kholo ea 2056 cm-1, ho na le lehetla le ikhethileng le shebaneng le ~ 2030 cm-1.Mokhoa oa ho lokisa tlhōrō ea Gaussian o ne o sebelisetsoa ho senya ka mokhoa o utloahalang ho ajoa ha mehlala ea RuNi sebakeng sa 2000-2100 cm-1 le ho ajoa ha CO sebakeng sa Ni (2056 cm-1) le sebaka sa Ru (2031-2039 cm).Litlhōrō tse peli li ne li adsorbed ka ho toba - 1) (setšoantšo sa 4b).Hoa thahasellisa hore ho tloha lisampole tsa Ru/Al2O3 (2060 cm–1) ho ea ho mehlala ea RuNi (2031-2039 cm–1), tlhōrō ea CO e amanang le linearly sebakeng sa Ru e ba le redshift e kholo mme e eketseha ka litaba tse ntseng li eketseha tsa Ru.Sena se bontša ho eketseha ha elektronegativity ea likaroloana tsa Ru ka har'a sampole ea RuNi, e leng phello ea phetisetso ea elektronike ho tloha ho Ni ho ea ho Ru, ho eketsa maikutlo a d-π electron ho tloha ho Ru ho ea ho CO 2π * orbital ea antibonding.Ho phaella moo, bakeng sa sampuli e nang le 0.4 mass% RuNi, ha ho tlhōrō ea adsorption ea bridging e ileng ea hlokomeloa, e bontšang hore likaroloana tsa Ru li teng e le liathomo tse ka thōko tsa Ni (SAA).Tabeng ea mehlala e nang le 0,6 wt.% RuNi le 2 wt.% RuNi, ho ba teng ha bridging CO ho tiisa hore ho na le li-multimers kapa lihlopha tsa Ru, tse lumellanang hantle le liphello tsa AC-HAADF-STEM.
a In situ CO-DRIFTS spectra ea Ni/Al2O3, Ru/Al2O3 le 0.4 wt.%, 0.6 wt.%, 2 wt.% RuNi disampole tse nang le phallo ea khase ea helium sebakeng sa 2100-1500 cm-1 bakeng sa 20 min.b Pontšo e lekantsoeng le ea Gaussian ea sampole ea RuNi/Al2O3 e nang le maemo a tsitsitseng a tlhoro le FWHM.c In situ Ru K-edge XANES spectra le d EXAFS Fourier fetola ponahalo ea lisampole tse fapaneng.Phetoho ea maqhubu a boima ba K2 ea XAFS K-edge Ru e thehiloeng holim'a maqhubu a Morlet bakeng sa mehlala ea e Ru e tsoang ho e Ru foil, f 0.4 wt% RuNi le g RuO2.“au” e bolela diyuniti tse sa tshwaneng.
Mokhoa o tloaelehileng oa sebopeho sa X-ray absorption sebopeho sa X-ray (XANES) se ile sa etsoa ho ithuta mekhoa ea elektronike le ea geometri ea lisampole tsa RuNi ka lisampole tsa Ru le RuO2.Joalokaha ho bontšitsoe feiga.4c, ha ho roala ha Ru ho fokotseha, matla a mohala o mosoeu a fokotseha butle-butle ho tloha ho mehlala ea Ru / Al2O3 ho ea ho mehlala ea RuNi.Ho sa le joalo, matla a mohala o mosoeu oa XANES spectrum ho K-edge ea Ni o bontša keketseho e fokolang ho tloha ho sampuli ea Ni ea pele ho ea ho mohlala oa RuNi (Supplementary Fig. 22).Sena se bontša phetoho tikolohong ea electron density le coordination ea metsoako ea Ru.Joalokaha ho bontšitsoe setšoantšong sa X-ray photoelectron spectroscopy (XPS) (Supplementary Fig. 23), tlhōrō ea Ru0 ea sampole ea RuNi e ile ea fetela ho matla a tlaase a tlamang 'me tlhōrō ea Ni0 e fetela ho matla a holimo a tlamang ha a bapisoa le monometallic Ru le Ni., e leng ho phaella moo e bontšang phetisetso ea elektronike ho tloha ho liathomo tsa Ni ho ea ho liathomo tsa Ru ho RuNi SAA.The Bader charge analysis of the RuNi SAA(111) surface e bonts'a hore liathomo tsa Ru tse ka thōko li jara liqoso tse mpe (Ruδ-) tse fetisitsoeng ho tloha ka tlas'a metsi a Ni atoms (Supplementary Fig. 24), e lumellanang le in situ DRIFTS le XPS liphello.Ho ithuta ka mokhoa o qaqileng oa ho hokahanya ha Ru (setšoantšo sa 4d), re ile ra etsa mokhoa o atolositsoeng oa X-ray absorption fine-grained spectroscopy (EXAFS) phetohong ea Fourier.Mohlala o nang le RuNi 0.4 wt.% e na le tlhōrō e bohale ho ~ 2.1 Å, e sebakeng se pakeng tsa likhetla tsa Ru-O (1.5 Å) le Ru-Ru (2.4 Å), tse ka amahanngoa le Ru-Ni coordination44, 45. Liphetho tse loketseng tsa data EXAFS (Tlhaloso ea Tlatsetso ea 5 le Lipalo tsa Tlatsetso 25-28) li bontša hore tsela ea Ru-Ni e na le nomoro ea ho hokahanya (CN) ea 5.4, ha ho se na khokahanyo ea Ru-Ru le Ru-O ho 0,4 wt.% Mohlala oa RuNi.Sena se tiisa hore liathomo tse ka sehloohong tsa Ru li qhalakanngoe ka athomo 'me li pota-potiloe ke Ni, li etsa motsoako oa monoatomic.Re lokela ho hlokomela hore tlhōrō ea tlhōrō (~ 2.4 Å) ea ho hokahanya ha Ru-Ru e hlaha ka mohlala oa 0,6 wt.% RuNi mme e ntlafatsoa ka sampuli ka 2 wt.% RuNi.Ka ho khetheha, EXAFS curve fitting e bontšitse hore linomoro tsa ho hokahanya ha Ru-Ru li eketsehile haholo ho tloha ho 0 (0.4 wt.% RuNi) ho ea ho 2.2 (0.6 wt.% RuNi) 'me ea eketseha ho ea ho 6.7 (2 wt.% .% RuNi), ka ho latellana. , e leng se bontšang hore ha boima ba Ru bo ntse bo eketseha, liathomo tsa Ru lia bokellana butle-butle.K2-weighted wave wave transform (WT) ea matshwao a Ru K-edge XAFS a ile a boela a sebediswa ho ithuta tikoloho ya kgokahanyo ya mefuta ya Ru.Joalokaha ho bontšitsoe feiga.4e, Ru foil lobes ho 2.3 Å, 9.7 Å-1 e bua ka monehelo oa Ru-Ru.Ka mohlala o nang le RuNi 0,4 wt.% (setšoantšo sa 4f) ha ho na li-lobe ho k = 9.7 Å-1 le 5.3 Å-1, ntle le tlamahano e bohareng ea Ru le liathomo tsa Ru le O (Fig. 4g);Ru-Ni li hlokomeloa ho 2.1 Å, 7.1 Å-1, e bontšang ho thehoa ha SAA.Ho phaella moo, EXAFS spectra ka K-bohale ba Ni bakeng sa disampole fapaneng ile a bontša ha ho na phapang e khōlō (Supplementary Fig. 29), e bontšang hore tšebelisano sebopeho sa Ni ke ka tlaase ho moo susumetsoa ke holim Ru liathomo.Ka bokhutšoanyane, liphetho tsa AC-HAADF-STEM, in situ CO-DRIFTS, le litekong tsa XAFS tsa situ li netefalitse ho lokisoa ka katleho ha li-catalyst tsa RuNi SAA le ho fetoha ha likaroloana tsa Ru ho Ni NPs ho tloha ho athomo e le 'ngoe ho ea ho li-multimers tsa Ru ka ho eketsa Ru mojaro.Ho phaella moo, litšoantšo tsa HAADF-STEM (Supplementary Fig. 30) le EXAFS spectra (Supplementary Fig. 31) ea li-catalysts tsa RuNi SAA tse sebelisitsoeng li bontšitse hore boemo ba ho qhalakanngoa le mokhoa oa ho hokahanya oa liathomo tsa Ru ha lia ka tsa fetoha haholo ka mor'a ho potoloha ha 5, ho paka. hore e tsitsitseng RuNi SAA catalyst .
Litekanyo tsa H2-TPD li ile tsa etsoa ho ithuta adsorption ea dissociative ea hydrogen ka li-catalysts tse fapa-fapaneng 'me liphello li bontšitse hore li-catalyst tsena kaofela li na le matla a matla a ho arohana a H2 ka tlhōrō ea desorption ho ~ 100 ° C (Supplementary Fig. 32).Liphello tsa tlhahlobo ea bongata (Supplementary Fig. 33) ha ea ka ea bontša kamano e hlakileng ea linear pakeng tsa reactivity le palo ea hydrogen desorption.Ho phaella moo, re ile ra etsa liteko ka li-isotopes tsa D2 'me ra fumana boleng ba kinetic isotope effect (KIE) ea 1.31 (TOFH / TOFD) (Supplementary Fig. 34), e fana ka maikutlo a hore ts'ebetso le ho arohana ha H2 ke tsa bohlokoa empa e se mehato e fokotsang tekanyo.Lipalo tsa DFT li ile tsa etsoa ho tsoela pele ho batlisisa ka boitšoaro ba adsorption le dissociation ea hydrogen ho RuNi SAA khahlanong le metallic Ni feela (Supplementary Fig. 35).Bakeng sa lisampole tsa RuNi SAA, limolek'hule tsa H2 li khetha chemisorb ho feta liathomo tsa Ru e le 'ngoe tse nang le matla a adsorption a -0.76 eV.Ka mor'a moo, haedrojene e ikarola ho ba liathomo tse peli tse sebetsang tsa H libakeng tse se nang letho tsa Ru-Ni RuNi SAA, e hlōlang mokoallo oa matla oa 0.02 eV.Ho phaella ho libaka tsa Ru, limolek'hule tsa H2 li ka boela tsa behoa ka chemisorbed libakeng tse ka holimo tsa liathomo tsa Ni tse haufi le Ru (adsorption energy: -0.38 eV) ebe li aroloa ho li-H tse peli sebakeng sa Ru-Ni le Ni-Ni sekoti.Tšitiso ea atomic 0.06 eV.Ho e-na le hoo, litšitiso tsa matla bakeng sa adsorption le dissociation ea limolek'hule tsa H2 holim'a Ni(111) holim'a -0.40 eV le 0.09 eV, ka ho latellana.Tšitiso e tlase haholo ea matla le liphapang tse sa reng letho li bonts'a hore H2 e ikarola habonolo holim'a li-surfactants tsa Ni le RuNi (Ni-site kapa Ru-site), e seng ntho ea bohlokoa e amang ts'ebetso ea eona ea matla.
Phatlalatso e sebetsang ea lihlopha tse itseng tse sebetsang e bohlokoa bakeng sa khetho ea hydrogenation ea li-substrates.Ka hona, re ile ra etsa lipalo tsa DFT ho batlisisa litlhophiso tse ka khonehang tsa 4-NS adsorption le libaka tse sebetsang sebakeng sa RuNi SAA (111), 'me liphello tsa ho ntlafatsa li bontšoa ho Supplementary Fig. 36e), moo liathomo tsa N li fumanehang libakeng tse sekoti tsa Ru-Ni le liathomo tse peli tsa O li kopantsoeng le sebopeho sa Ru-Ni se bonts'a boemo bo tlase ba matla a adsorption (-3.14 eV).Sena se fana ka maikutlo a puso ea adsorption e ntle ea thermodynamically ha e bapisoa le litlhophiso tse otlolohileng le tse ling tse tšoanang (Supplementary Fig. 36a-d).Ho phaella moo, ka mor'a ho phatlalatsoa ha 4-HC ho RuNi SAA (111), bolelele ba tlamo ea N-O1 (L (N-O1)) sehlopheng sa nitro bo eketsehile ho 1.330 Å (Fig. 5a), e leng ngata haholo. nako e telele ho feta bolelele ba gaseous 4- NS (1.244 Å) (Supplementary Fig. 37), esita le ho feta L (N-O1) (1.315 Å) ka Ni (111).Sena se bontša hore adsorption e kentsoeng ea li-bond tsa N-O1 holim'a RuNi PAA e matlafalitsoe haholo ha e bapisoa le Ni(111) ea pele.
Litlhophiso tsa Adsorption tsa 4-HC ho Ni(111) le RuNi SAA (111) (Eads) libaka (mahlakoreng le holimo).Ru – violet, Ni – tala, C – lamunu, O – khubelu, N – blue, H – tšoeu.b In situ FT-IR spectra of gaseous and chemisorbed 4-HC on monometallic surfactants Ni, Ru, RuNi (0.4 wt. %) le 2 wt.% RuNi, ka ho latellana.c Normalized in situ XANES and d-phase-corred Fourier EXAFS at the Ru K-edge of 0.4 wt % RuNi PAA during 4-NS adsorption (RuNi SAA–4NS) and hydrogenation steps (RuNi SAA–4NS–H2) .Transformation spectra ;…e Projection density of states (PDOS) ea sebaka sa pele sa RuNi SAA(111), N-O1 ka gaseous 4-NS and adsorbed 4-NS on RuNi SAA(111).“au” e bolela diyuniti tse sa tshwaneng.
Ho tsoela pele ho hlahloba boitšoaro ba adsorption ea 4-NS, in situ FT-IR litekanyo li ile tsa etsoa ho Ni monometallic, Ru monometallic, 0.4 wt% RuNi (SAA), le 2 wt% RuNi catalysts (Fig. 5b).The FT-IR spectrum ea gaseous 4-NS e bonts'itse litlhoro tse tharo tse ikhethang ho 1603, 1528, le 1356 cm-1, tse abetsoeng ν(C=C), νas(NO2), le νs(NO2)46,47, 48.Ka pel'a Ni monometallic, li-redshifts tsa lihlopha tse tharo kaofela lia hlokomeloa: v(C=C) (1595 cm–1), νas(NO2) (1520 cm–1), le νs(NO2) (1351 cm–1) ., e bonts'ang chemisorption ea lihlopha tsa C = C le -NO2 holim'a Ni holim'a Ni (mohlomong, ka ho hlophisoa ha adsorption e tšoanang).Bakeng sa sampole ea monometallic Ru, li-redshifts tsa lihlopha tsena tse tharo (1591, 1514, le 1348 cm-1, ka ho latellana) tse amanang le monometallic Ni li ile tsa fumanoa, e leng se bontšang ho ntlafala hanyenyane ha lihlopha tsa nitro le li-bond С=С ho Ru.Tabeng ea 0,4 wt.% RuNi (SAA), sehlopha sa ν(C=C) se bohareng ba 1596 cm–1, e haufi haholo le sehlopha sa monometallic Ni (1595 cm–1), e leng se bontšang hore lihlopha tsa vinyl li atisa ho adsorb Ni ho RuNi. Libaka tsa SAA.Ho feta moo, ho fapana le monometallic catalyst, matla a lekanyelitsoeng a sehlopha sa νs(NO2) (1347 cm-1) a fokola haholo ho feta sehlopha sa νas(NO2) (1512 cm-1) ho 0.4 wt.% RuNi (SAA) ) , e 'nileng ea amahanngoa le ho arohana ha NO bond ho -NO2 ho theha nitroso e bohareng ho latela lithuto tse fetileng49,50.Ketsahalo e ts'oanang e ile ea boela ea bonoa sampuling e nang le litaba tsa RuNi tsa 2 wt.%.Liphetho tse ka holimo li tiisa hore phello ea synergistic ea litsi tsa bimetallic ho PAA RuNi e khothalletsa polarization le ho arohana ha lihlopha tsa nitro, tse lumellanang hantle le tlhophiso e ntle ea adsorption e fumanoang ke lipalo tsa DFT.
In situ XAFS spectroscopy e ile ea etsoa ho ithuta phetoho e matla ea sebopeho sa elektroniki le boemo ba khokahano ea RuNi SAA nakong ea 4-NS adsorption le catalytic reaction.Joalokaha ho ka bonoa ho tloha ho K-edge XANES spectrum ea Ru (Setšoantšo sa 5c), ka mor'a ho phatlalatsoa ha 4-HC, 0,4 wt.% RuNi PAA, moeli oa ho monya o fetisetsoa haholo ho matla a phahameng, a tsamaeang le ho eketseha ha matla a mohala o mosoeu, e leng se bontšang hore mefuta ea Ru Oxidation ea Karolo e etsahala ka lebaka la ho fetisoa ha elektronike ho tloha ho Ru ho ea ho 4-NS.Ho phaella moo, Fourier e lokisoang ka mohato oa EXAFS spectrum ea adsorbed 4-NS RuNi SAA (Fig. 5d) e bonts'a ntlafatso e hlakileng ea matšoao ho ~ 1.7 Å le ~ 3.2 Å, e amanang le ho thehoa ha Ru-O coordination.The XANES le EXAFS spectra ea 0.4 wt% RuNi SAA e khutletse boemong ba eona ba pele ka mor'a ente ea metsotso ea 30 ea khase ea hydrogen.Liketsahalo tsena li bontša hore lihlopha tsa nitro li adsorbed libakeng tsa Ru ka li-bond tsa Ru-O tse thehiloeng litšebelisanong tsa elektronike.Ha e le sebopeho sa XAFS sa moeli oa Ni-K in situ (Supplementary Fig. 38), ha ho liphetoho tse totobetseng tse ileng tsa hlokomeloa, tse ka 'nang tsa bakoa ke phello ea ho hlapolloa ha liathomo tsa Ni ka karolo ea bongata holim'a likaroloana tsa Ni.Boima bo boletsoeng esale pele ba linaha (PDOS) ea RuNi SAA (setšoantšo sa 5e) se bontša hore boemo bo sa sebetseng ba sehlopha sa nitro ka holimo ho boemo ba Femi bo atoloha le ho tsamaea ka tlase ho boemo ba Femi boemong ba adsorbed, e leng ho phaella moo e bontšang hore li-electrone tse tsoang ho d- boemo ba phetoho ea RuNi SAA ho ea sebakeng se se nang batho ho −NO2.Phapang ea boima ba tefiso (Supplementary Fig. 39) le tlhahlobo ea tefiso ea Bader (Supplementary Fig. 40) e bonts'a hore sekhahla sa elektronike se kopantsoeng sa 4-NS se bokella ka mor'a ho phatlalatsoa ha eona holim'a RuNi SAA (111).Ho phaella moo, tefiso ea -NO2 e ile ea eketseha haholo ha e bapisoa le sehlopha sa vinyl ho 4-NS ka lebaka la ho fetisoa ha elektronike ho sebopeho sa Ru-Ni, e bontšang ts'ebetso e khethehileng ea NO bond sehlopheng sa nitro.
In situ FT-IR e ne e etsoa ho shebella ts'ebetso ea catalytic ea 4-NS hydrogenation reaction ka li-catalyst sampuli (setšoantšo sa 6).Bakeng sa lisebelisoa tsa nickel tsa pele (setšoantšo sa 6a), ho fokotseha hanyenyane feela ka bongata ba lihlopha tsa nitro (1520 le 1351 cm-1) le C = C (1595 cm-1) ha ho feta H2 bakeng sa metsotso e 12, e bontša hore − Activation NO2 le C=C li batla li fokola.Boteng ba monometallic Ru (Setšoantšo sa 6b), sehlopha sa ν(C=C) (ho 1591 cm–1) se sesefala ka potlako ka har'a metsotso e 0-12, ha lihlopha tsa νs(NO2) le νas(NO2) li fokotsehile ka matla. .Butle Sena se bontša ts'ebetso e khethehileng ea sehlopha sa vinyl bakeng sa hydrogenation, e lebisang ho thehoeng ha 4-nitroethylbenzene (4-NE).Tabeng ea 0,4 wt.% RuNi (SAA) (Setšoantšo sa 6c), sehlopha sa νs(NO2) (1347 cm–1) se nyamela ka potlako ka ho phalla ha haedrojene, e tsamaeang le ho bola butle-butle ha ν(N=O );sehlopha se secha se shebaneng le 1629 cm-1 le sona se ile sa bonoa, se hlahisoang ke ho thothomela ha NH.Ho feta moo, sehlopha sa ν(C=C) (1596 cm–1) se bonts'a phokotseho e nyane feela kamora metsotso e 12.Phetoho ena e matla e tiisa polarization le hydrogenation ea -NO2 ho -NH2 ka 0.4 wt% RuNi (SAA) e thehiloeng ho chemoselectivity e ikhethang ho 4-aminostyrene.Bakeng sa mohlala oa 2 wt.% RuNi (Setšoantšo sa 6d), ntle le ponahalo ea sehlopha se secha sa 1628 cm-1 se boleloang ke δ (NH), sehlopha sa ν(C = C) se fokotseha haholo 'me se nyamela ka sehlopha se ntseng se eketseha sa sehlopha sa nitro (1514). le 1348 cm–1).Sena se bontša hore C = C le -NO2 li sebelisoa ka katleho ka lebaka la ho ba teng ha litsi tsa Ru-Ru le Ru-Ni interfacial, ka ho latellana, tse lumellanang le ho thehoa ha 4-NE le 4-AE ho 2 wt.% RuNi catalyst.
In situ FT-IR spectra ea 4-NS hydrogenation ka pel'a monometallic Ni, b monometallic Ru, c 0.4 wt% RuNi SAA, le d 2 wt% RuNi ho H2 phallo ka 1700-1240 cm- Range 1 e tlalehiloe e le khase e arabelang ka mor'a metsotso e 0, 3, 6, 9 le 12, ka ho latellana.“au” e bolela diyuniti tse sa tshwaneng.Kabo e ka bang teng ea matla le meaho e tsamaellanang e ntlafalitsoeng bakeng sa C=C hydrogenation le NO scission into 4-NS on e Ni(111) and f RuNi SAA(111) surfaces.Ru – violet, Ni – tala, C – lamunu, O – khubelu, N – blue, H – tšoeu."lipapatso", "IS", "TS", le "FS" li emela boemo ba papatso, boemo ba pele, boemo ba phetoho, le boemo ba ho qetela, ka ho latellana.
Litsela tse ka bang teng bakeng sa phetoho ea 4-NS ho Ni(111) le RuNi SAA(111), ho kenyeletsoa C=C hydrogenation le NO bond cleavage, li ile tsa fuputsoa ka lipalo tsa DFT ho tsoela pele ho hlakisa karolo ea bohlokoa ea 4-NS.Likarolo tsa sebopeho sa Ru-Ni bakeng sa tlhahiso ea lipheo tsa 4-AS.Bakeng sa sebaka sa Ni (111) (Setšoantšo sa 6e), litšitiso tsa matla bakeng sa NO scission le hydrogenation ea lihlopha tsa vinyl sethaleng sa pele ke 0.74 le 0.72 eV, ka ho latellana, e bontšang hore chemoselective hydrogenation ea lihlopha tsa nitro ka 4-HC ke. sa rateheng.bakeng sa libaka tsa nickel tse monometallic.Ho fapana le hoo, mokoallo oa matla bakeng sa NO dissociation ke 0.46 eV feela e phahameng ho feta ea RuNi SAA (111), e leng tlase haholo ho feta ea C = C bond hydrogenation (0.76 eV) (Fig. 6f).Sena se tiisa ka mokhoa o hlakileng hore litsi tsa li-interfacial tsa Ru-Ni li theola ka katleho mokoallo oa matla bakeng sa NO scission lihlopheng tsa nitro, e leng se lebisang ho phokotso e ntle ea thermodynamically ea lihlopha tsa nitro ha li bapisoa le lihlopha tsa C = C sebakeng sa surfactant sa RuNi, se lumellanang le liphello tsa liteko.
Mokhoa oa ho itšoara le li-curve tsa matla a 4-NS hydrogenation ho RuNi SAA li ile tsa batlisisoa ho latela lipalo tsa DFT (setšoantšo sa 7), 'me tlhophiso e qaqileng ea adsorption ea mehato e meholo e bontšoa ho Supplementary Fig. 41. Ho ntlafatsa lenaneo la ho bala, litšitiso tse hlahisang matla bakeng sa limolek'hule tsa metsi li ne li qheletsoe ka thoko ho lipalo.poleiti mehlala9,17.Joalokaha ho bontšitsoe feiga.7, limolek'hule tsa 4-NS li qala ho kenngoa ka mokhoa o ts'oanang ho "surfactant" ea RuNi, 'me liathomo tse peli tsa O ka har'a sehlopha sa nitro li tlameletsoe ho li-interfacial centers tsa Ru-Ni (S0; mohato oa I).Ka mor'a moo, NO bond e khomaretsoeng sebakeng sa Ru e robehile, e tsamaeang le ho thehoa ha nitroso intermediate (C8H7NO *) sebakeng sa marang-rang sa Ru-Ni le O * sebakeng se se nang letho sa Ni (S0 → S1 ka TS1; matla mokoallo: 0.46 eV, mohato oa bobeli ).Li-radicals tsa O* li entsoe ka hydrogenated ke liathomo tse sebetsang tsa H ho etsa limolek'hule tsa H2O tse nang le exotherm ea 0.99 eV (S1 → S2).Litšitiso tsa matla bakeng sa hydrogenation ea C8H7NO * mahareng ( Tlatsetso Figures 42 le 43) li bontša hore reactive H liathomo ho tloha sekoti Ru-Ni libaka preferentially hlasela O liathomo ho feta N liathomo, ho fella ka C8H7NOH * (S2 → S4; matla mokoallo TS2: 0.84 eV, mohato III).Liathomo tsa N ho C8H7NOH* li ile tsa etsoa hydrogenated ho theha C8H7NHOH* ka mor'a ho tšela mokoallo oa 1.03 eV (S4→S6; mohato oa IV), e leng mohato o hlalosang oa karabelo eohle.Ka mor'a moo, tlamo ea N-OH ho C8H7NHOH* e ile ea robeha ho Ru-Ni interface (S6 → S7; mokoallo oa matla: 0.59 eV; sethala sa V), ka mor'a moo OH* e ile ea kenngoa ka hydrogenated ho HO (S7 → S8; exotherm: 0.31 eV ) Ka mor'a moo, liathomo tsa N tsa libaka tse sekoti tsa Ru-Ni tse C8H7NH * li ile tsa boela tsa kenngoa ka hydrogenated ho theha C8H7NH2 * (4-AS) ka mokoallo oa matla oa 0.69 eV (S8 → S10; mohato oa VI).Qetellong, limolek'hule tsa 4-AS le HO li ile tsa senyeha ho tloha holim'a RuNi-PAA, 'me mokelikeli o khutlela sebakeng sa oona sa pele (mohato oa VII).Sebopeho sena se ikhethileng sa sefahleho pakeng tsa liathomo tse le 'ngoe tsa Ru le li-substrates tsa Ni, tse tsamaeang le phello ea synergistic ea doping e amohelang RuNi SAA, e fella ka ts'ebetso e ikhethang le chemoselectivity ea 4-NS hydrogenation.
Raese.4. Setšoantšo sa moralo oa mochine oa hydrogenation reaction ea NS ho 4-AS holim'a RuNi PAA holim'a metsi.Ru – violet, Ni – tala, C – lamunu, O – khubelu, N – blue, H – tšoeu.Inset e bonts'a kabo ea matla a ka bang teng a 4-NS hydrogenation holim'a RuNi SAA(111) holim'a metsi, a baloang ho latela DFT."S0" e emela boemo ba pele, 'me "S1-S10" e emela letoto la linaha tsa papatso.“TS” e emetse boemo ba phetoho.Linomoro tse ka har'a li-brackets li emela litšitiso tsa matla tsa mehato e meholo, 'me linomoro tse setseng li emela matla a adsorption a li-intermediates tse lumellanang.
Ka hona, li-catalysts tsa RuNi SAA li ile tsa fumanoa ho sebelisoa li-electrosubstitution reactions pakeng tsa RuCl3 le Ni NPs tse fumanoang ho li-precursors tsa LDH.Ha ho bapisoa le monometallic Ru, Ni le li-catalyst tse ling tse sa tšoaneng tse tlalehiloeng, RuNi SAA e hlahisitsoeng e bontšitse katleho e phahameng ea catalytic bakeng sa 4-NS chemoselective hydrogenation (4-AS chai:> 99%; TOF value: 4293 h-1).Sebopeho se kopantsoeng se kenyeletsang AC-HAADF-STEM, in situ CO-DRIFTS, le XAFS e tiisitse hore liathomo tsa Ru li ne li sa sebetse ho Ni NPs ka tekanyo ea athomo e le 'ngoe ka li-bond tsa Ru-Ni, tse neng li tsamaea le ho fetisoa ha elektronike ho tloha Ni ho ea ho Ru.In situ XAFS, liteko tsa FT-IR, le lipalo tsa DFT li bontšitse hore sebaka sa marang-rang sa Ru-Ni se sebetsa e le sebaka se sebetsang sa ka hare bakeng sa ts'ebetso e khethehileng ea NO bond sehlopheng sa nitro;synergism pakeng tsa Ru le libaka tsa boahelani tsa Ni li thusa ho kenya ts'ebetsong le hydrogenation, kahoo e ntlafatsa haholo ts'ebetso ea catalytic.Mosebetsi ona o fana ka temohisiso mabapi le kamano pakeng tsa libaka tse sebetsang ka bobeli le boitšoaro bo susumetsang ba SAA boemong ba athomo, ho bula tsela bakeng sa moralo o utloahalang oa li-catalyst tse ling tse peli tse nang le khetho e lakatsehang.
Li-reagents tsa tlhahlobo tse sebelisitsoeng tekong li rekiloe ho 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 le nitrostyrene.Metsi a hloekisitsoeng a ne a sebelisoa litekong tsohle.
Li-NiAl LDH tsa Hierarchical li ile tsa etsoa e le li-precursors ka kholo ea in situ.Ntlha ea pele, urea (3.36 g), Al2 (SO4) 3 · 18H2O (9.33 g) le tartrate ea sodium (0.32 g) e ile ea qhibiliha ka metsi a hloekisitsoeng (140 ml).Tharollo e hlahisoang e ile ea fetisetsoa ho autoclave e entsoeng ka Teflon 'me e futhumetse ho 170 ° C bakeng sa 3 h.Sephetho se hlahisoang se ne se hlatsuoa ka metsi a silafetseng 'me se omisitsoe ka ho feletseng, ka mor'a moo se ne se calcined ka 500 ° C (2 ° C min-1; 4 h) ho fumana amorphous Al2O3.Joale Al2O3 (0.2 g), Ni(NO3)2 6H2O (5.8 g) le NH4NO3 (9.6 g) li ne li qhalakanngoa metsing a hloekisitsoeng (200 ml) 'me pH e fetotsoe ho ~ 6.5 ka ho eketsa 1 mol l -1 metsi a ammonia..Ho emisoa ho ile ha fetisetsoa ka botlolong 'me ea bolokoa ho 90 ° C bakeng sa 48 h ho fumana NiAl-LDH.Joale NiAl-LDH phofo (0.3 g) e ile ea fokotseha ka molapo oa H2 / N2 (10/90, v/v; 35 ml min–1) ho 500 ° C bakeng sa 4 h (tekanyo ea mocheso: 2 ° C min -1 ).Ho lokisoa ha lisampole tsa nickel ea monometallic (Ni/Al2O3) e kentsoeng ho Al2O3 ea amorphous.Mehlala ea bimetallic e kentsoeng ea RuNi e entsoe ka mokhoa oa electrodisplacement.Ka tloaelo, sampuli e ncha ea Ni/Al2O3 (0.2 g) e ile ea qhalakanngoa ka 30 ml ea metsi a hloekileng, joale tharollo ea RuCl3 (0.07 mmol l-1) e ile ea eketsoa butle-butle 'me ea tsosoa ka matla ka metsotso e 60 tlas'a tšireletso ea moea oa N2. .Sephetho se hlahisitsoeng se ne se le centrifuged, se hlatsuoa ka metsi a hloekileng, 'me se omisitsoe ka ontong ea vacuum ka 50 ° C bakeng sa 24 h, ho fumana sampuli e nang le 0.1% RuNi.Pele ho tlhahlobo ea matla, lisampole tse sa tsoa etsoa li ile tsa fokotsoa pele ho phallo ea H2/N2 (10/90, v/v) ka 300°C (sekhahla sa mocheso: 2°C min–1) bakeng sa 1 h, ebe se futhumatsoa ka hare. N2 E pholile ho isa mocheso oa kamore.Bakeng sa litšupiso: lisampole tse nang le litaba tsa Ru/Al2O3 tsa 0.4% le 2% ka boima, tse nang le litaba tsa nnete tsa Ru tsa 0.36% ka boima le 2.3% ka boima, li lokiselitsoe ka pula ka pula le ho futhumatsoa ho 300 ° C (tšebeliso ea H2 / N2 : 10/90, v/v, sekhahla sa ho futhumatsa: 2 °C min–1) ka lihora tse 3.
Liteko tsa X-ray diffraction (XRD) li ile tsa etsoa ho Bruker DAVINCI D8 ADVANCE diffractometer e nang le mohloli oa mahlaseli a Cu Kα (40 kV le 40 mA).Shimadzu ICPS-7500 Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) e ile ea sebelisoa ho fumana bongata ba 'nete ba likarolo lisampoleng tse fapaneng.Litšoantšo tsa electron microscopy (SEM) li ile tsa nkoa ho sebelisoa maekerosekoupo ea elektronike ea Zeiss Supra 55.Liteko tsa N2 adsorption-desorption li ile tsa etsoa ka sesebelisoa sa Micromeritics ASAP 2020 mme sebaka se itseng sa holim'a metsi se ile sa baloa ka mokhoa oa Brunauer-Emmett-Teller (BET) multipoint.Litšobotsi tsa transmission electron microscopy (TEM) li ile tsa etsoa ho JEOL JEM-2010 microscope ea phetisetso e phahameng ea boemo bo phahameng.High Aberration Corrected Scanning Transmission Electron Microscope Dark Field (AC-HAADF) – STEM with FEI Titan Cube Themis G2 300 e nang le spherical aberration corrector le Energy Dispersive X-ray Spectroscopy (EDS) le lisebelisoa tsa JEOL JEM-ARM200F) le litekanyo tsa 'mapa tsa EDS .Sebopeho se setle sa X-ray absorption spectroscopy (XAFS) in situ K-edge ea Ru le Ni K-edge e ile ea lekanngoa ka mecha ea 1W1B le 1W2B ea Beijing Synchrotron Radiation Facility (BSRF) ea Institute of High Energy Physics (IHEP), Chaena. .Academy of Sciences (KAN).Liteko tsa pulsed CO chemisorption le mocheso-programmed hydrogen desorption (H2-TPD) li ile tsa etsoa ka sesebelisoa sa Micromeritics Autochem II 2920 se sebelisang mochine oa motlakase oa mocheso (TCD).Liteko tsa in situ DRIFTS le FT-IR li entsoe ho Bruker TENSOR II infrared spectrometer e nang le sele e fetotsoeng ea in situ reaction le sebui se hlokolosi haholo sa MCT.Mekhoa e qaqileng ea ho khetholla batho e hlalositsoe ho Tlhahisoleseding ea Tlatsetso.
Ntlha ea pele, substrate (4-NS, 1 mmol), solvent (ethanol, 8 ml) le catalyst (0.02 g) e kenyelelitsoe ka hloko ho 25 ml ea tšepe e sa hloekang ea autoclave.Joale sekontiri se ile sa hloekisoa ka ho feletseng ka 2.0 MPa (> 99.999%) hydrogen makhetlo a 5, 'me ea hatelloa le ho tiisoa ho 1.0 MPa le H2.Karabelo e ile ea etsoa ka 60 ° C ka lebelo le tsitsitseng la 700 rpm.Ka mor'a karabelo, lihlahisoa tse hlahisitsoeng li ile tsa khetholloa ke GC-MS 'me tsa hlahlojoa ka bongata ho sebelisoa Shimadzu GC-2014C gas chromatography system e nang le GSBP-INOWAX capillary column (30 m×0.25 mm×0.25 mm) le mochine oa FID.Phetoho ea 4-nitrostyrene le khetho ea lihlahisoa li ile tsa khethoa ka tsela e latelang:
Litekanyetso tsa Turnover frequency (TOF) li ne li baloa joalo ka mol 4-NS e fetoletsoeng ka libaka tsa tšepe tsa mol ka hora (mol4-NS mol-1 h-1) e ipapisitse le phetoho e tlase ea 4-NS (~ 15%).Ha e le palo ea li-node tsa Ru, li-interface tsa Ru-Ni le palo eohle ea liathomo tsa tšepe tse holim'a metsi.Bakeng sa tlhahlobo ea recyclability, catalyst e ile ea bokelloa ka centrifugation ka mor'a karabelo, e hlatsuoa ka makhetlo a mararo ka ethanol, ebe e kenngoa hape ka autoclave bakeng sa potoloho e latelang ea catalytic.
Lipalo tsohle tsa density functional theory (DFT) li entsoe ho sebelisoa Vienna ab initio simulation package (VASP 5.4.1).Mosebetsi oa Generalized Gradient Approximation (GGA) PBE o sebelisetsoa ho hlalosa phapanyetsano ea elektronike le maemo a ho hokahanya.Mokhoa oa Projector Augmented Wave (PAW) o sebelisoa ho hlalosa tšebelisano lipakeng tsa nuclei ea athomo le lielektrone.Mokhoa oa Grimm DFT-D3 o hlalosa phello ea litšebelisano tsa van der Waals pakeng tsa substrate le sebopeho.Palo ea Litšitiso tsa Matla ka ho Hloaela Elastic Bands ka Image Boost (CI-NEB) le Mekhoa ea Dimer.Ho ile ha etsoa tlhahlobo ea khafetsa ea li-oscillations, e tiisang hore ho na le makhetlo a le mong feela a inahaneloang sebakeng se seng le se seng sa phetoho (Lipalo tsa Tlatsetso 44-51).Lipalo tse qaqileng haholoanyane li hlalositsoe boitsebisong bo eketsehileng.
Lintlha tse ka sehloohong tse tšehetsang merero ea sehlooho sena li fanoe ka lifaele tsa mohloli oa mohloli.Lintlha tse ling tse amanang le phuputso ena li fumaneha ho tsoa ho bangoli ba fapaneng ka kopo e utloahalang.Sengoliloeng sena se fana ka lintlha tsa mantlha.
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