Enkosi ngokundwendwela i-Nature.com.Usebenzisa uguqulelo lwebrawuza enenkxaso enyiniweyo yeCSS.Ngowona mava angcono, sicebisa ukuba usebenzise isikhangeli esihlaziyiweyo (okanye uvale iModi yokuThelela kwi-Internet Explorer).Ukongeza, ukuqinisekisa inkxaso eqhubekayo, sibonisa indawo ngaphandle kwezitayela kunye neJavaScript.
Ubonisa ikharawusi yezilayidi ezithathu ngaxeshanye.Sebenzisa amaqhosha angaphambili nalandelayo ukutyhutyha izilayidi ezithathu ngexesha, okanye sebenzisa amaqhosha esilayidi ekupheleni ukuya kwizilayidi ezithathu ngexesha.
Uyilo kunye nophuhliso lwezixhobo zokusebenza eziphezulu zifumene ingqwalasela enkulu kwiimpendulo ezikhethiweyo ze-hydrogenation kodwa zihlala zingumngeni omkhulu.Apha sichaza i-monatomic RuNi alloy (SAA) apho i-athomu ye-Ru nganye ingenakunyakaziswa kumphezulu we-Ni nanoparticles nge-Ru-Ni coordination, ehamba kunye nokudluliselwa kwe-electron ukusuka kwi-subsurface ye-Ni ukuya kwi-Ru.Kulwazi lwethu, i-catalyst engcono kakhulu ye-0.4% RuNi SAA ngaxeshanye ibonise umsebenzi ophezulu (ixabiso le-TOF: 4293 h-1) kunye ne-chemoselectivity ye-hydrogenation ekhethiweyo ye-4-nitrostyrene ukuya kwi-4-aminostyrene (isivuno:> 99%), inqanaba eliphezulu ngo. xa kuthelekiswa nee-catalysts ezaziwayo.Uvavanyo lwe-in situ kunye nokubala kwethiyori lubonisa ukuba iisayithi ze-Ru-Ni interface, njengeendawo zangaphakathi ezisebenzayo, zikhuthaza ukuphulwa okukhethiweyo kwe-NO bonds kunye nomqobo wamandla ophantsi we-0.28 eV.Ukongezelela, i-synergistic Ru-Ni catalysis ithanda ukubunjwa kwe-intermediates (C8H7NO * kunye ne-C8H7NOH *) kwaye ikhawuleza inyathelo lokumisela izinga (i-hydrogenation ye-C8H7NOH *).
I-amines enevumba elisebenzayo, iibhloko zokwakha ezibalulekileyo zeekhemikhali ezilungileyo, zinezicelo ezibalulekileyo zemizi-mveliso ekuveliseni amayeza, iikhemikhali ze-agrochemicals, ii-pigments kunye neepolymers1,2,3.I-catalytic hydrogenation yeekhompawundi ze-nitroaromatic ezifumaneka lula ngaphezu kwee-catalysts ezingafaniyo ziye zatsala ingqalelo enkulu njengendlela ehambelana nokusingqongileyo kunye nendlela enokuphinda isetyenziswe ukuhlanganiswa kwee-amine ezinexabiso elongezelelweyo4,5,6,7.Nangona kunjalo, ukunciphisa i-chemoselective yamaqela -NO2 ngelixa kugcinwa amanye amaqela ancitshisiweyo afana ne-alkenes, alkynes, halogens, okanye i-ketones yinto enqwenelekayo kakhulu kodwa kunomngeni8,9,10,11.Ngoko ke, ukusetyenziswa okunengqiqo kwee-catalysts ezihlukeneyo zokunciphisa ngokuthe ngqo kwamaqela -NO2 ngaphandle kokuchaphazela ezinye iibhondi ezinciphisayo zinqweneleka kakhulu12,13,14.Uninzi lwee-catalysts ezingenalusizo lwesinyithi ziye zaphandwa ukwenza i-hydrogenation ye-nitroarenes, kodwa iimeko zokusabela ezinzima zithintela ukusetyenziswa kwazo okubanzi15,16.Nangona ii-catalysts zentsimbi ezihloniphekileyo (ezifana ne-Ru17, Pt18, 19, 20 okanye Pd21, 22, 23) zisebenza phantsi kweemeko zokusabela ezithambileyo, zihlala zihlupheka ngenxa yeendleko eziphezulu, ukukhethwa okuncinci, kunye nokusetyenziswa kweathomu ephantsi.Ke ngoko, ukufumana iicatalysts ezisebenza kakhulu kunye nekhemoselective ngoyilo olunengqiqo kunye nokulungiswa kakuhle kwesakhiwo esihle kuhlala kungumngeni omkhulu24,25,26.
I-Monatomic Alloy (SAA) i-catalysts inokusebenza kakuhle kwesinyithi, ijometri ekhethekileyo kunye nesakhiwo sombane, ibonelela ngeendawo ezizodwa ezisebenzayo, kunye nokubonelela ngentsebenzo ebalaseleyo ye-catalytic ngokwaphula i-characification linear scaling behaviour27,28,29,30,31.I-athomu enye ejoyiweyo kunye neeathom zesinyithi ezisindleke kwi-SAA zinokusebenza njengeziza ezisebenza kabini, ziququzelela ukusebenza kwee-substrates ezininzi okanye zivumele amanyathelo okusabela okusisiseko ukuba kwenzeke kwiindawo ezahlukeneyo32,33,34.Ukongezelela, imibutho ye-heterometallic phakathi kwee-athomu zetsimbi ezingcolileyo ezizimeleyo kunye neentsimbi ezibambayo zingakhokelela kwimiphumo ye-idiosyncratic synergistic, nangona ukuqonda kwemiphumo enjalo ye-synergistic phakathi kweeseti ezimbini zeendawo zetsimbi kwinqanaba le-athomu zihlala ziphikisana35,36,37,38.Ukwenzela i-hydrogenation ye-nitroarenes esebenzayo, izakhiwo ze-elektroniki kunye nejometri yeendawo ezisebenzayo kufuneka ziyilwe ngendlela yokukhawulezisa ukusebenza kwamaqela e-nitro kuphela.Njengomthetho, amaqela e-electron-deficient nitro adsorbed kakhulu kwimimandla ye-nucleophilic ye-catalyst surface, ngelixa kwindlela elandelayo ye-hydrogenation, i-cooperative catalysis yeendawo ezisebenzayo ezingabamelwane ziya kudlala indima ebalulekileyo ekulawuleni ukusebenza kwakhona kunye ne-chemoselectivity4,25.Oku kusishukumisele ukuba siphonononge ii-catalysts ze-SAA njengomgqatswa othembisayo wokuphucula ukusebenza kakuhle kwe-chemoselective hydrogenation yeekhompawundi ze-nitroaromatic, kunye nokucacisa ngakumbi unxulumano phakathi kolwakhiwo lwesayithi olusebenzayo kunye nokusebenza kwe-atom ye-catalytic.
Apha, ii-catalysts ezisekelwe kwi-monatomic RuNi alloys zalungiswa ngokusekelwe kwindlela yokwenziwa kwezigaba ezibini, kubandakanywa ukuguqulwa kwesakhiwo se-topological ye-layer double hydroxide (LDH) elandelwa yi-electro-displacement treatment.I-RuNi SAA ibonisa ukusebenza kakuhle kwe-catalytic (>99% isivuno) kwi-chemoselective hydrogenation ye-4-nitrostyrene ukuya kwi-4-aminostyrene kunye ne-turnover frequency (TOF) ukuya kuthi ga kwi- ~ 4300 mol-mol Ru-1 h-1, eyona iphezulu inqanaba phakathi kwe-heterogeneous catalysts ezibhaliswe phantsi kweemeko zokusabela ezifanayo.I-electron microscopy kunye ne-spectroscopic characterization ibonise ukuba ii-athom ze-Ru ezizimeleyo zisasazwa kumphezulu we-Ni nanoparticles (~ 8 nm), zenza ulungelelwaniso lwe-Ru-Ni oluzinzile, olukhokelela kwiindawo ze-Ru ezingalunganga (Ruδ-) ngenxa yokudluliselwa kwe-electron ukusuka kwi-subsurface ye-Ni ukuya kwi-Ru. .Kwi-situ FT-IR, izifundo ze-XAFS kunye ne-density functional theory (DFT) izibalo ziqinisekisile ukuba iziza kwi-interface ye-Ru-Ni njengeziza zangaphakathi ezisebenzayo ziququzelela i-nitro.I-adsorption esebenzayo (0.46 eV) yohlukile kuleyo ye-monometallic nickel catalyst.(0.74 eV).Ukongezelela, ukuchithwa kwe-hydrogen kwenzeka kwiindawo ezingabamelwane ze-Ni, ezilandelwa yi-hydrogenation ye-intermediates (C8H7NO * kunye ne-C8H7NOH *) kwiindawo ze-Ruδ.Impembelelo ye-synergistic yenkxaso ye-doping kwi-RuNi SAA catalyst iphumela kumsebenzi obalaseleyo we-nitroarenes hydrogenation kunye nokukhetha, okunokwandiswa kwezinye izinto ezinqabileyo ezinqabileyo ze-catalyst zetsimbi ezisetyenziswa kwi-activant reactions.
Ngokusekwe kwinguqu ye-topology yesakhiwo se-leyared hydroxide (LDH) yangaphambili, silungiselele i-monometallic Ni efakwe kwi-amorphous Al2O3 substrates.Emva koko, isethi ye-RuNi / Al2O3 iisampulu ze-bimetallic ezinomxholo ohlukeneyo we-Ru (0.1-2 wt%) zenziwe ngokuchanekileyo nge-electrodisplacement ukufaka i-athomu ye-Ru ebusweni be-Ni nanoparticles (NPs) (Umfanekiso 1a).Imilinganiselo edibeneyo ye-plasma ye-atomic emission spectrometry (ICP-AES) inika ngokucacileyo ukubunjwa kwe-elemental ye-Ru kunye ne-Ni kwezi sampuli (iTheyibhile eyoNgezelelweyo ye-1), esondele kwi-theory feedstock loading.Imifanekiso ye-SEM (i-Supplementary Figure 1) kunye neziphumo zeBET (Amanani abongezelelweyo 2-9 kunye neTheyibhile eyoNgezelelweyo ye-1) ibonisa ngokucacileyo ukuba isakhiwo se-morphological kunye nommandla othile wendawo yeesampuli ze-RuNi / Al2O3 azikho utshintsho olucacileyo ngexesha lonyango lwe-electrochemical.– inkqubo yokuhamba.Umzekelo we-X-ray (umzobo 1b) ubonisa uluhlu lweempawu ezibonisa iimpawu kwi-2θ 44.3 °, 51.6 °, kunye ne-76.1 °, ebonisa izigaba (111), (200), kunye (220) ye-Ni (JCPDS 004-0850). ).Ngokucacileyo, iisampulu zeRuNi azibonakalisi i-metallic okanye i-oxidized Ru, ebonisa ukusasazeka okuphezulu kweentlobo zeRu.Imilinganiselo ye-electron microscopy (TEM) yokuhanjiswa kweesampuli ze-monometallic ze-Ni kunye ne-RuNi (umzobo 1c1-c8) zibonisa ukuba i-nickel nanoparticles zihlakazwe kakuhle kwaye zingenakunyakaziswa kwi-amorphous Al2O3 inkxaso kunye nobukhulu obufanayo (7.7-8.3 nm).Imifanekiso ye-HRTEM (Imifanekiso ye-1d1-d8) ibonisa ixesha elifanayo le-lattice malunga ne-0.203 nm kwiisampuli ze-Ni kunye ne-RuNi, ehambelana ne-Ni (111) iindiza, nangona kunjalo, i-lattice edges of particles Ru particles ayikho.Oku kubonisa ukuba iiathom zikaRu zisasazwe kakhulu kumphezulu wesampulu kwaye azichaphazeli ixesha le-Ni lattice.Okwangoku, i-2 wt% i-Ru / Al2O3 yenziwe ngendlela ye-deposition-deposition njengendlela yokulawula, apho amaqela e-Ru asasazwa ngokufanayo kumphezulu we-Al2O3 substrate (iFigs ezongezelelweyo 10-12).
iSkimu sendlela yokudibanisa iisampulu ze-RuNi/Al2O3, b iipatheni ze-X-ray diffraction ye-Ni/Al2O3 kunye neesampulu ezahlukeneyo ze-RuNi/Al2O3.c1−c8 TEM kunye ne-d1−d8 HRTEM imifanekiso yegrayiti enesuntswana lobungakanani bonikezelo lwe-monometallic Ni, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0, 8% wt., 1 wt.Umfanekiso onemigca.% kunye ne-2 wt.% RuNi.“au” ithetha iiyunithi ezingafanelekanga.
Umsebenzi we-catalytic weesampuli ze-RuNi zafundwa nge-chemoselective hydrogenation ye-4-nitrostyrene (4-NS) ukuya kwi-4-aminostyrene (4-AS).Ukuguqulwa kwe-4-NS kwi-substrate ye-Al2O3 ecocekileyo yayiyi-0.6% kuphela emva kweeyure ze-3 (iThebhile eyoNgezelelweyo 2), ebonisa umphumo omncinci we-Al2O3.Njengoko kubonisiwe kwifig.I-2a, i-nickel catalyst yasekuqaleni ibonise umsebenzi ophantsi kakhulu we-catalytic kunye nokuguqulwa kwe-4-NS ye-7.1% emva kweeyure ze-3, ngelixa ukuguqulwa kwe-100% kunokufezekiswa phambi kwe-monometallic Ru catalyst phantsi kweemeko ezifanayo.Zonke ii-catalysts ze-RuNi zibonise umsebenzi owandisiweyo we-hydrogenation (ukuguqulwa: ~ 100%, i-3 h) xa kuthelekiswa neesampuli ze-monometallic, kwaye izinga lokuphendula lihambelana kakuhle nomxholo we-Ru.Oku kuthetha ukuba amaqhekeza e-Ru adlala indima ebalulekileyo kwinkqubo ye-hydrogenation.Kuyathakazelisa ukuba ukukhethwa kwemveliso (Umfanekiso 2b) uyahluka kakhulu kuxhomekeke kwi-catalyst.Kwi-catalyst ye-nickel ecocekileyo engasebenziyo, eyona mveliso yayiyi-4-nitroethylbenzene (4-NE) (ukukhethwa: 83.6%) kunye nokukhethwa kwe-4-AC kwakuyi-11.3%.Kwimeko ye-monometallic Ru, i-C = C ibhondi kwi-4-NS ichaphazeleka ngakumbi kwi-hydrogenation kune-NO2, ekhokelela ekubunjweni kwe-4-nitroethylbenzene (4-NE) okanye i-4-aminoethyl benzene (4-AE);ukhetho lwe-4-AC lwaluyi-15.7% kuphela.Okumangalisa kukuba, i-RuNi catalysts enomxholo ophantsi we-Ru (0.1-0.4 wt%) ibonise ukukhetha okuhle kakhulu (> 99%) ukuya kwi-4-aminostyrene (4-AS), ebonisa ukuba i-NO2 kwaye ayikho i-vinyl, i-chemoselective ekhethekileyo.Xa umxholo weRu udlula i-0.6 wt.%, ukhetho lwe-4-AS lwehla ngokukhawuleza ngokunyuka kwe-Ru, ngelixa ukukhethwa kwe-4-AE kwanda endaweni yoko.Kwi-catalyst equkethe i-2 wt% i-RuNi, zombini amaqela e-nitro kunye ne-vinyl ayenziwe nge-hydrogenated kakhulu ngokukhetha okuphezulu kwi-4-AE ye-98%.Ukufunda umphumo we-Ru dispersion state kwi-catalytic reaction, i-0.4 wt% i-Ru / Al2O3 iisampulu zalungiswa (iMizobo eyoNgezelelweyo ye-10, i-13 kunye ne-14) apho amasuntswana e-Ru achithwa kakhulu njenge-athomu nganye elandelwa ngamaqela ambalwa e-Ru.(quasi-atomic Ru).Ukusebenza kwe-catalytic (i-Supplementary Table 2) ibonisa ukuba i-0.4 wt% Ru / Al2O3 iphucula ukhetho lwe-4-AS (67.5%) xa kuthelekiswa nesampuli ye-2 wt% Ru / Al2O3, kodwa umsebenzi uphantsi kakhulu (ukuguqulwa: 12.9).%Iiyure ezi-3).Ngokusekelwe kwinani elipheleleyo leendawo zetsimbi kumphezulu ogqitywe yi-CO pulsed chemisorption measurements, i-turnover frequency (TOFmetal) ye-RuNi catalyst ifunyenwe kwi-4-NS yokuguqulwa ephantsi (i-Supplementary Fig. 15), ebonisa umkhwa wokuqala wokunyusa ukwanda. kwaye emva koko ukuncipha ngokunyuka kokunyuka kwe-Ru yokulayisha (iFig. 16 eyoNgezelelweyo).Oku kuphakamisa ukuba ayizizo zonke iisayithi zetsimbi ezisebenza njengeendawo zemveli ezisebenzayo zeRuNi catalysts.Ukongezelela, i-TOF ye-RuNi catalyst yabalwa ukusuka kwiindawo ze-Ru ukuze ibonise ngakumbi umsebenzi wayo we-catalytic wangaphakathi (Umfanekiso 2c).Njengoko umxholo weRu unyuka ukusuka kwi-0.1 wt.% ukuya kwi-0.4 wt.I-% RuNi catalysts ibonise amaxabiso e-TOF phantse angaguqukiyo (4271-4293 h-1), ebonisa ukugcinwa kwee-RuNi ngamasuntswana e-atomic dispersion (mhlawumbi ngokusekwa kwe-RuNi SAA).) kwaye isebenza njengeyona ndawo isebenzayo.Nangona kunjalo, ngokunyuka okungaphezulu kokulayishwa kweRu (ngaphakathi kwe-0.6-2 wt%), ixabiso le-TOF liyancipha kakhulu, elibonisa utshintsho kwisakhiwo sangaphakathi seziko elisebenzayo (ukusuka kwi-atomic dispersion ukuya kwi-Ru nanoclusters).Ukongezelela, kulwazi lwethu, i-TOF ye-0.4 wt% ye-RuNi (SAA) i-catalyst ikwinqanaba eliphezulu phakathi kwee-catalysts zetsimbi ezichazwe ngaphambili phantsi kweemeko zokusabela ezifanayo (I-Supplementary Table 3), ebonisa ngakumbi ukuba i-monoatomic RuNi alloys ibonelela ngeepropati ezintle kakhulu.umboniso.Umzobo owongezelelweyo we-17 ubonisa ukusebenza kwe-catalytic ye-0.4 wt% ye-RuNi (SAA) i-catalyst kuxinzelelo oluhlukeneyo kunye namaqondo okushisa e-H2, apho uxinzelelo lwe-H2 lwe-MPa eyi-1 kunye nobushushu bokuphendula be-60 °C busetyenziswe njengemilinganiselo efanelekileyo yokusabela.isampuli equlathe RuNi 0.4 wt.I-% (Umfanekiso we-2d), kwaye akukho kuncipha okuphawulekayo kumsebenzi kunye nesivuno sabonwa kwimijikelezo emihlanu elandelelanayo.Imifanekiso ye-X-ray kunye ne-TEM ye-0.4 wt% i-RuNi catalyst esetyenziswe emva kwemijikelezo ye-5 (iMizobo eyoNgezelelweyo ye-18 kunye ne-19) ayizange ibonise utshintsho oluphawulekayo kwisakhiwo se-crystal, ebonisa ukuzinza okuphezulu kokuphendula okukhethiweyo kwe-hydrogenation.Ukongezelela, i-0.4 wt% i-RuNi (SAA) i-catalyst inika kwakhona isivuno esihle kakhulu se-amines kwi-chemoselective hydrogenation yezinye i-nitroaromatic compounds eziqukethe i-halogens, i-aldehydes, kunye namaqela e-hydroxyl (i-Supplementary Table 4), ebonisa ukusetyenziswa kwayo kakuhle.
ukuguqulwa kweCatalytic kunye nokusabalalisa kwe-b yeemveliso ze-4-nitrostyrene hydrogenation phambi kwe-monometallic Ni, Ru, kunye ne-RuNi catalysts enomxholo ohlukeneyo we-Ru (0.1-2 wt%), c kwi-catalytic dynamic range, Turnover frequency (TOF) kwi-RuNi catalysts c ngokuxhomekeke Ru per mole.d Uvavanyo lokusetyenziswa kwakhona kwe-0.4 wt.% I-RuNi catalyst ye-catalyst emihlanu elandelelanayo.I-ln (C0/C) isekwe kwixesha lokusabela kwe-hydrogenation ye-e-nitrobenzene kunye ne-f-styrene ngomxube we-nitrobenzene kunye ne-styrene (1:1).Iimeko zokuphendula: 1 mmol reagent, 8 ml solvent (ethanol), 0.02 g catalyst, 1 MPa H2, 60 ° C, 3 iiyure.Imivalo yemposiso ichazwa njengophambuko olusemgangathweni lweziphindaphindo ezintathu.
Ukuphanda ngakumbi umahluko obalulekileyo we-chemoselective, i-hydrogenation yomxube we-styrene kunye ne-nitrobenzene (1:1) nayo yenziwa kubukho be-monometallic catalysts i-Ni, i-Ru, i-0.4 wt% i-RuNi, kunye ne-2 wt% i-RuNi, ngokulandelelana (umzobo owoNgezelelweyo 20).Nangona i-chemoselectivity ye-reaction hydrogenation yamaqela asebenzayo ihambelana, eneneni kukho iiyantlukwano ekukhethweni kwe-intramolecular kunye ne-intermolecular hydrogenation ngenxa yeziphumo ze-allosteric ze-molecular.Njengoko kubonisiwe kwifig.I-2e,f, igophe ln(C0/C) ngokuchasene nexesha lokuphendula inika umgca othe ngqo ukusuka kwimvelaphi, ebonisa ukuba zombini i-nitrobenzene kunye ne-styrene ziimpendulo zolandelelwano lokuqala.I-Monometallic nickel catalysts ibonise umlinganiselo ophantsi kakhulu we-hydrogenation rate constants kuzo zombini i-p-nitrobenzene (0.03 h-1) kunye ne-styrene (0.05 h-1).Ngokucacileyo, umsebenzi okhethwayo we-styrene hydrogenation (umlinganiselo ongaguqukiyo: 0.89 h-1) waphunyezwa kwi-Ru monometallic catalyst, engaphezulu kakhulu kunomsebenzi we-nitrobenzene hydrogenation (umlinganiselo ongaguqukiyo: 0.18 h-1).Kwimeko ye-catalyst equkethe i-RuNi (SAA) 0.4 wt.I-% i-nitrobenzene hydrogenation ithandeka ngakumbi kune-styrene hydrogenation (umlinganiselo oqhubekayo: 1.90 h-1 vs. 0.04 h-1), ebonisa ukhetho lweqela -NO2.phezu kwe-C hydrogenation = ibhondi C. I-catalyst ene-2 ​​wt.% I-RuNi, umlinganiselo ongaguquguqukiyo we-hydrogenation ye-nitrobenzene (1.65 h-1) yehla xa kuthelekiswa ne-0.4 wt.I-% ye-RuNi (kodwa isephezulu kune-mono-metal catalyst), ngelixa izinga le-hydrogenation ye-styrene landa kakhulu (izinga eliqhubekayo: 0.68).h−1).Oku kubonisa kwakhona ukuba ngempembelelo ye-synergistic phakathi kwe-Ni kunye ne-Ru, umsebenzi we-catalytic kunye ne-chemoselectivity ngokubhekiselele kumaqela e-NO2 anyuswe kakhulu xa kuthelekiswa ne-RuNi SAA.
Ukujonga ngokubonakalayo amazwe okusasazwa kwe-Ru kunye ne-Ni iikhompawundi, indlela yokucinga usebenzisa i-ring-angle ephezulu yokuskena i-electron microscopy ene-aberration correction (AC-HAADF-STEM) kunye ne-element mapping by energy dispersive spectroscopy (EDS) yenziwa.Imephu yokuqala ye-EMF yesampula kunye ne-0.4 wt% yomxholo we-RuNi (Umfanekiso 3a, b) ibonisa ukuba i-Ru ihlakazeke kakhulu ngokufanayo kwi-nanoparticles ye-nickel, kodwa kungekhona kwi-substrate ye-Al2O3, umfanekiso ohambelana ne-AC-HAADF-STEM (Fig. 3c) ibonisa, Kuyabonakala ukuba umphezulu we-Ni NPs uqulethe iindawo ezininzi eziqaqambileyo zobukhulu beathom ye-athomu ye-Ru (ephawulwe ngeentolo eziluhlaza), ngelixa kungekho maqela okanye i-Ru nanoparticles ibonwa.Umfanekiso we-3d), ebonisa ukubunjwa kwee-alloys ze-monatomic RuNi.Kwisampuli equlethe i-RuNi 0.6 wt.I-% (Umfanekiso we-3e), i-athomu ye-Ru enye kunye nenani elincinci le-Ru bulk particles yabonwa kwi-Ni NPs, ebonisa ukuhlanganiswa okuncinci kwe-athomu ye-Ru ngenxa yokwanda komthwalo.Kwimeko yesampula kunye ne-2 wt% umxholo we-RuNi, amaninzi amaninzi amakhulu ama-Ru kwi-Ni NPs afunyenwe kumfanekiso we-HAADF-STEM (Umfanekiso we-3f) kunye ne-EDS imephu ye-elemental (i-Supplementary Fig. 21), ebonisa ukuqokelela okukhulu kwe-Ru. .
umfanekiso we-HAADF-STEM, b ohambelana nomfanekiso we-EDS wemephu, c umfanekiso ophezulu we-AC-HAADF-STEM umfanekiso, d ukhulise umfanekiso we-STEM kunye nokusabalalisa ukuqina okuhambelanayo kwesampuli ye-0.4 wt% ye-RuNi.(e, f) AC–HAADF–STEM imifanekiso yeesampulu eziqulethe i-0.6 wt.% I-RuNi kunye ne-2 wt.% RuNi, ngokulandelelanayo.
Xa kuthelekiswa neesampuli ze-Ni / Al2O3 kunye ne-Ru / Al2O3, i-DRIFTS i-spectra ye-CO adsorption in situ yenziwa (umzobo 4a) ukuqhubela phambili ukufundisisa iinkcukacha zesakhiwo seesampuli eziqukethe i-0.4 wt.%, 0.6 wt.% kunye ne-2 wt.% I-RuNi.I-CO adsorption kwisampulu ye-Ru/Al2O3 inika incopho ephambili kwi-2060 cm-1 kunye nenye incopho ebanzi kwi-1849 cm-1 ibangelwa kumgca we-CO adsorption kwi-Ru kunye ne-bridging kwii-athom ezimbini ze-Ru ezingabamelwane, ngokulandelelana kwe-CO39,40.Kwisampula ye-Ni ye-monometallic, i-peak eyomeleleyo ibonwa kuphela kwi-2057 cm-1, ebizwa ngokuba yi-CO41,42 yomgca kwingingqi ye-nickel.Kwisampulu ye-RuNi, ngaphezu kweyona nto iphakamileyo kwi-2056 cm-1, kukho ihlombe elicacileyo elijoliswe kwi- ~ 2030 cm-1.Indlela yokulinganisa i-Gaussian peak yayisetyenziselwa ukusabalalisa ngokufanelekileyo ukuhanjiswa kweesampuli ze-RuNi kwi-2000-2100 cm-1 uluhlu kunye nokusabalalisa kwe-CO kummandla we-Ni (2056 cm-1) kunye nommandla we-Ru (2031-2039 cm).Iincopho ezimbini zibhengezwe ngokulandelelana - 1) (Umfanekiso 4b).Kuyathakazelisa ukuba, ukusuka kwiisampuli ze-Ru / Al2O3 (2060 cm-1) ukuya kwiisampuli ze-RuNi (2031-2039 cm-1), i-CO ephezulu ehambelana nomgca kwingingqi ye-Ru ithatha i-redshift ebalulekileyo kwaye inyuka ngokunyuka kwe-Ru content.Oku kubonisa ukwanda kwe-electronegativity ye-RuNi particles kwisampuli ye-RuNi, eyisiphumo sokudluliselwa kwe-electron ukusuka ku-Ni ukuya ku-Ru, ukwandisa i-d-π impendulo ye-electron ukusuka ku-Ru ukuya kwi-antibonding CO 2π * orbital.Ukongeza, kwisampulu equlethe i-0.4 mass% ye-RuNi, akukho ncopho ye-adsorption ye-bridging yabonwa, ebonisa ukuba iinqununu ze-Ru zikhona njenge-atom ze-Ni ezizimeleyo (SAA).Kwimeko yeesampuli kunye ne-0.6 wt.% I-RuNi kunye ne-2 wt.I-% ye-RuNi, ubukho be-bridging CO buqinisekisa ubukho be-Ru multimers okanye i-clusters, evumelana kakuhle neziphumo ze-AC-HAADF-STEM.
i-In situ CO-DRIFTS i-spectra ye-Ni / Al2O3, i-Ru / Al2O3 kunye ne-0.4 wt.%, 0.6 wt.%, i-2 wt.% Iisampuli ze-RuNi kunye nokuhamba kwegesi ye-helium kuluhlu lwe-2100-1500 cm-1 kwi-20 min.b I-spectra ene-Scaled kunye ne-Gaussian efakwe kwi-RuNi / Al2O3 isampuli eneendawo eziphakamileyo eziphezulu kunye ne-FWHM.c In situ Ru K-edge XANES spectra kunye d EXAFS Fourier transform spectra of ezahlukeneyo iisampulu.K2-weighted wavelet transform of XAFS K-edge Ru signals based on Morlet wavelet for e Ru samples from e Ru foil, f 0.4 wt% RuNi and g RuO2.“au” ithetha iiyunithi ezingafanelekanga.
I-normalized in situ i-X-ray yokufunxa i-X-ray Isakhiwo sokufunxa i-X-ray (i-XANES) i-spectra yenzelwe ukufunda izakhiwo ze-elektroniki kunye nejometri yeesampuli ze-RuNi kunye ne-Ru foil kunye neesampuli ze-RuO2.Njengoko kubonisiwe kwifig.I-4c, njengoko ukulayisha kwe-Ru kuncipha, ubukhulu bomgca omhlophe buyancipha ngokuthe ngcembe ukusuka kwiisampuli ze-Ru / Al2O3 ukuya kwiisampuli ze-RuNi.Okwangoku, ubukhulu bomgca omhlophe we-spectrum ye-XANES kwi-K-edge ye-Ni ibonisa ukunyuka okuncinci ukusuka kwisampuli ye-Ni yokuqala ukuya kwisampuli ye-RuNi (i-Supplementary Fig. 22).Oku kubonisa utshintsho kwi-electron density and coordination environment of the Ru compounds.Njengoko kuboniswe kwi-X-ray photoelectron spectroscopy (XPS) spectra (Fig. 23 eyoNgezelelweyo), i-Ru0 peak ye-sampulu ye-RuNi yatshintshela kumandla aphantsi okubopha kunye ne-Ni0 ephezulu yatshintshela kumandla aphezulu okubopha xa kuthelekiswa ne-monometallic Ru kunye ne-Ni., eyongezelela ibonisa ukuhanjiswa kwe-electron ukusuka kwi-athomu ye-Ni ukuya kwi-athomu ye-Ru e-RuNi SAA.Uhlalutyo lwentlawulo ye-Bader ye-RuNi SAA (111) i-surface ibonisa ukuba ii-athomu ze-Ru ezizimeleyo zithwala iindleko ezimbi (Ruδ-) ezidluliselwe kwi-subsurface ye-Ni athomu (i-Supplementary Fig. 24), ehambelana ne-DRIFTS kunye neziphumo ze-XPS.Ukufunda ulwakhiwo oluneenkcukacha lweRu (Umfanekiso we-4d), senze i-X-ray eyongeziweyo yokufunxa i-spectroscopy (EXAFS) kwinguqu ye-Fourier.Isampuli equlethe i-RuNi 0.4 wt.I-% inencopho ebukhali kwi ~ 2.1 Å, ebekwe kummandla ophakathi kwe-Ru-O (1.5 Å) kunye ne-Ru-Ru (2.4 Å) amaqokobhe, anokuthi afakwe kwi-Ru-Ni coordination44, 45. Iziphumo zokufaneleka kwedatha EXAFS (Itheyibhile eyoNgezelelweyo ye-5 kunye neMifanekiso eyoNgezelelweyo ye-25-28) ibonisa ukuba indlela ye-Ru-Ni inenombolo yokulungelelanisa (CN) ye-5.4, ngelixa kungekho ukulungelelaniswa kwe-Ru-Ru kunye ne-Ru-O kwi-0.4 wt.% Isampulu yeRuNi.Oku kuqinisekisa ukuba ii-athomu eziphambili ze-Ru zihlakazekile kwaye zijikelezwe nguNi, zenza i-alloy monoatomic.Kufuneka kuqatshelwe ukuba i-peak intensity (~ 2.4 Å) yokulungelelaniswa kwe-Ru-Ru ibonakala kwisampuli ye-0.6 wt.I-% RuNi kwaye iphuculwe kwisampuli nge-2 wt.% I-RuNi.Ngokukodwa, i-EXAFS curve fitting ibonise ukuba amanani okulungelelaniswa kwe-Ru-Ru anyuke kakhulu ukusuka kwi-0 (0.4 wt.% RuNi) ukuya kwi-2.2 (0.6 wt.% RuNi) kwaye yanda ngakumbi kwi-6.7 (2 wt.% .% RuNi), ngokulandelanayo. , ebonisa ukuba njengoko umthwalo we-Ru ukhula, i-athomu ye-Ru idibanisa ngokuthe ngcembe.I-K2-weighted wavelet transform (WT) ye-Ru K-edge XAFS imiqondiso yaphinda yasetyenziselwa ukufunda ulungelelwaniso olusingqongileyo lweentlobo ze-Ru.Njengoko kubonisiwe kwifig.I-4e, i-Ru foil lobes kwi-2.3 Å, 9.7 Å-1 ibhekisela kwigalelo likaRu-Ru.Kwisampulu equlethe i-RuNi 0.4 wt.% (Umfanekiso 4f) akukho lobes k = 9.7 Å-1 kunye 5.3 Å-1, ngaphandle bond central Ru kunye athom Ru kunye O (Fig. 4g);I-Ru-Ni ijongwa kwi-2.1 Å, 7.1 Å-1, ebonisa ukusekwa kwe-SAA.Ukongezelela, i-spectra ye-EXAFS kwi-K-edge ye-Ni yeesampuli ezahlukeneyo ibonisa ukuba akukho mahluko abalulekileyo (i-Supplementary Fig. 29), ebonisa ukuba ulwakhiwo lokulungelelaniswa kwe-Ni aluphenjelelwa ngaphantsi kwe-athomu ye-Ru.Ngamafutshane, iziphumo ze-AC-HAADF-STEM, kwi-situ CO-DRIFTS, kunye ne-situ XAFS imifuniselo iqinisekisa ukulungiswa okuyimpumelelo kwe-RuNi SAA catalysts kunye nokuvela kwamaqhekeza e-Ru kwi-Ni NPs ukusuka kwi-athomu enye ukuya kwi-multimers ye-Ru ngokunyusa Ru umthwalo.Ukongezelela, imifanekiso ye-HAADF-STEM (i-Supplementary Fig. 30) kunye ne-EXAFS spectra (i-Supplementary Fig. 31) ye-RuNi SAA catalysts esetyenzisiweyo ibonise ukuba i-dispersion state kunye nesakhiwo sokulungelelaniswa kwe-athomu ye-Ru ayizange itshintshe kakhulu emva kwemijikelezo ye-5, ibonakalisa. ukuba i-RuNi SAA ezinzileyo i-catalyst.
Imilinganiselo ye-H2-TPD yenzelwe ukufundisisa i-adsorption ye-dissociative ye-hydrogen kwii-catalysts ezahlukahlukeneyo kwaye iziphumo zibonise ukuba zonke ezi zixhobo zinamandla okuchithwa kwe-H2 kunye ne-desorption peak kwi ~ 100 ° C (i-Supplementary Fig. 32).Iziphumo zohlalutyo lobungakanani (i-Supplementary Fig. 33) ayizange ibonise ulungelelwaniso olucacileyo lomgca phakathi kwe-reactivity kunye nenani le-hydrogen desorption.Ukongezelela, senze iimvavanyo kunye ne-D2 isotopes kwaye safumana ixabiso le-kinetic isotope (KIE) ye-1.31 (TOFH / TOFD) (I-Fig.Ubalo lwe-DFT lwenziwa ukuphanda ngakumbi i-adsorption kunye nokuziphatha kwe-dissociation ye-hydrogen kwi-RuNi SAA ngokuchasene ne-metallic Ni yodwa (iFig. 35 eyoNgezelelweyo).Kwiisampulu ze-RuNi SAA, iimolekyuli ze-H2 zikhethwa ngokukhethekileyo kwi-chemisorb kune-athomu ye-Ru enye enamandla e-adsorption -0.76 eV.Emva koko, i-hydrogen iyahlukana ibe yi-athomu ezimbini ezisebenzayo ze-H kwiindawo ezingenanto ze-Ru-Ni RuNi SAA, ukoyisa umqobo wamandla we-0.02 eV.Ukongeza kwiindawo ze-Ru, iimolekyuli ze-H2 nazo zinokuthi zifakwe kwi-chemisorbed kwiindawo eziphezulu ze-atom ze-Ni ezikufutshane ne-Ru (amandla e-adsorption: -0.38 eV) kwaye emva koko zahlulwa zibe zi-H ezimbini kwiindawo ezingenanto ze-Ru-Ni kunye ne-Ni-Ni.Umqobo weAtomic 0.06 eV.Ngokuchasene noko, izithintelo zamandla ze-adsorption kunye nokuchithwa kwee-molecule ze-H2 kwi-Ni (111) indawo -0.40 eV kunye ne-0.09 eV, ngokulandelanayo.Isithintelo samandla esiphantsi kakhulu kunye nokwahlukana okungabalulekanga kubonisa ukuba i-H2 iyahlukana ngokulula kumphezulu we-Ni kunye ne-RuNi surfactants (i-Ni-site okanye i-Ru-site), engeyiyo into ephambili echaphazela umsebenzi wayo we-catalytic.
I-adsorption esebenzayo yamaqela athile asebenzayo ibalulekile kwi-hydrogenation ekhethiweyo ye-substrates.Ngoko ke, senze izibalo ze-DFT ukuphanda ulungelelwaniso olunokwenzeka lwe-4-NS adsorption kunye neendawo ezisebenzayo kwi-RuNi SAA (111) surface, kunye neziphumo zokuphucula ziboniswa kwi-Supplementary Fig. 36. Uqwalaselo olubonakalayo olufanayo (umzobo 5a kunye neFig. 36e), apho ii-athom ze-N zibekwe kwiindawo ezingenanto ze-Ru-Ni kunye nee-athomu ezimbini ze-O zibophelelwe kwi-interface ye-Ru-Ni ibonisa inqanaba lamandla eliphantsi le-adsorption (-3.14 eV).Oku kuphakamisa i-thermodynamically ethandeka ngakumbi ulawulo lwe-adsorption xa kuthelekiswa nolungelelwaniso oluthe nkqo kunye nolunye oluhambelanayo (Umfanekiso owongezelelweyo 36a-d).Ukongezelela, emva kokubhengezwa kwe-4-HC kwi-RuNi SAA (111), ubude bebhondi ye-N-O1 (L (N-O1)) kwiqela le-nitro landa kwi-1.330 Å (Umfanekiso 5a), eninzi kakhulu. ubude kunobude be-gaseous 4- NS (1.244 Å) (I-Fig. 37 eyoNgezelelweyo), nokuba idlula i-L (N-O1) (1.315 Å) kwi-Ni (111).Oku kubonisa ukuba i-adsorption esebenzayo yeebhondi ze-N-O1 kumphezulu we-RuNi PAA iphuculwe kakhulu xa kuthelekiswa ne-Ni (111) yokuqala.
ulungelelwaniso lwe-Adsorption ye-4-HC kwi-Ni(111) kunye ne-RuNi SAA (111) (Eads) imiphezulu (icala kunye neembono eziphezulu).Ru – violet, Ni – green, C – orenji, O – obomvu, N – blue, H – white.b In situ FT-IR spectra of gaseous kunye chemisorbed 4-HC kwi monometallic surfactants Ni, Ru, RuNi (0.4 wt. %) kunye 2 wt.% RuNi, ngokulandelelanayo.c Iqhelekile kwi-situ XANES kunye ne-d-phase-elungiswe i-Fourier EXAFS kwi-Ru K-edge ye-0.4 wt % RuNi PAA ngexesha le-4-NS adsorption (RuNi SAA–4NS) kunye namanyathelo e-hydrogenation (RuNi SAA–4NS–H2) .Imbonakalo yenguqu yembonakalo ;...e Uqikelelo loxinaniso lwamazwe (PDOS) kumphezulu wokuqala we-RuNi SAA(111), N-O1 kwigesi 4-NS kunye ne-adsorbed 4-NS kwi-RuNi SAA(111).“au” ithetha iiyunithi ezingafanelekanga.
Ukuvavanya ngakumbi ukuziphatha kwe-adsorption ye-4-NS, kwi-situ imilinganiselo ye-FT-IR yenziwa kwi-Ni monometallic, i-Ru monometallic, i-0.4 wt% i-RuNi (SAA), kunye ne-2 wt% i-RuNi catalysts (Umfanekiso 5b).I-FT-IR spectrum yegesi ye-4-NS ibonise iincopho ezintathu zeempawu kwi-1603, 1528, kunye ne-1356 cm-1, eyabelwa ukuba ν(C=C), νas(NO2), kunye νs(NO2)46,47, 48.Phambi kwe-Ni ye-monometallic, ii-redshifts zontathu iibhendi ziyabonwa: v(C=C) (1595 cm–1), νas(NO2) (1520 cm–1), kunye νs(NO2) (1351 cm–1) ., ebonisa i-chemisorption ye-C = C kunye namaqela -NO2 kumphezulu we-Ni (okunokwenzeka kakhulu, kuqwalaselo lwe-adsorption ehambelanayo).Kwisampulu ye-monometallic Ru, i-redshifts yala maqela mathathu (1591, 1514, kunye ne-1348 cm-1, ngokulandelanayo) ngokumalunga ne-monometallic Ni yafunyanwa, ebonisa ukunyuswa kancinane kwamaqela e-nitro kunye С=С iibhondi kwi-Ru.Kwimeko ye-0.4 wt.I-% RuNi (SAA), i-ν(C=C) ibhendi igxile kwi-1596 cm–1, ekufutshane kakhulu ne-monometallic Ni band (1595 cm–1), ebonisa ukuba amaqela e-vinyl akholisa uku-adsorb i-Ni kwi-RuNi. Iindawo ze-SAA.Ukongeza, ngokungafaniyo ne-monometallic catalyst, ukuqina kwe-νs(NO2) band (1347 cm-1) buthathaka kakhulu kunebhendi ye-νas(NO2) (1512 cm-1) kwi-0.4 wt.% RuNi (SAA) ) , edibene nokuqhawulwa kwe-NO bond ukuya -NO2 ukwenza i-nitroso ephakathi ngokwezifundo zangaphambili49,50.Isiganeko esifanayo siphinde sabonwa kwisampuli kunye nomxholo we-RuNi we-2 wt.%.Iziphumo ezingentla ziqinisekisa ukuba umphumo we-synergistic wamaziko e-bimetallic kwi-PAA i-RuNi ikhuthaza i-polarization kunye nokuchithwa kwamaqela e-nitro, ehambelana kakuhle nokulungelelaniswa kwe-adsorption efanelekileyo efunyenwe ngokubala kwe-DFT.
In situ XAFS spectroscopy yaqhutyelwa ukufunda inguqu eguquguqukayo yesakhiwo se-elektroniki kunye nemeko yolungelelaniso lwe-RuNi SAA ngexesha le-4-NS adsorption kunye ne-catalytic reaction.Njengoko kunokubonwa kwi-K-edge XANES spectrum ye-Ru (Fig. 5c), emva kwe-adsorption ye-4-HC, i-0.4 wt.I-% RuNi PAA, i-edge yokufunxa iguqulelwe kakhulu kumandla aphezulu, ehamba kunye nokunyuka kokuqina komgca omhlophe, obonisa ukuba iintlobo ze-Ru I-oxidation ye-partial oxidation yenzeke ngenxa yokudluliselwa kwe-electron ukusuka kwi-Ru ukuya kwi-4-NS.Ukongeza, i-Fourier elungiswayo yesigaba se-EXAFS spectrum ye-adsorbed 4-NS RuNi SAA (Fig. 5d) ibonisa ukongezwa okucacileyo kweempawu kwi ~ 1.7 Å kunye ne ~3.2 Å, ehambelana nokusekwa kolungelelwaniso lwe-Ru-O.I-XANES kunye ne-EXAFS ye-spectra ye-0.4 wt% i-RuNi SAA ibuyele kwisimo sayo sokuqala emva kwe-30 yemizuzu ye-injection yegesi ye-hydrogen.Ezi ziganeko zibonisa ukuba amaqela e-nitro adsorbed kwiindawo ze-Ru ngokusebenzisa iibhondi ze-Ru-O ngokusekelwe kwintsebenziswano ye-elektroniki.Ngokuphathelele i-spectra ye-XAFS ye-Ni-K edge in situ (Fig. 38 eyoNgezelelweyo), akukho tshintsho lucacileyo luye lwabonwa, olunokuthi lube ngenxa yesiphumo sokuhlanjululwa kwee-athomu ze-Ni kwisigaba sobuninzi kumphezulu wamasuntswana e-Ni.Uxinaniso oluqikelelweyo lwamazwe (PDOS) lweRuNi SAA (umzobo 5e) lubonisa ukuba imeko engahlaliyo yeqela le-nitro ngaphezu kwenqanaba le-Femi libanzi kwaye lihamba ngaphantsi kwenqanaba le-Femi kwi-adsorbed state, ebonisa ukuba i-electrons ukusuka kwi-d- Imeko yeRuNi SAA itshintshela kwisimo esingahlali mntu e-NO2.Umahluko woxinaniso lwentlawulo (umzobo owongezelelweyo we-39) kunye nohlalutyo lwentlawulo ye-Bader (umzobo owongezelelweyo we-40) ibonisa ukuba ukuxinana kwe-electron edibeneyo ye-4-NS iqokelela emva kokubhengezwa kwayo ebusweni be-RuNi SAA (111).Ukongezelela, i-NO2 yentlawulo yoxinaniso yanda kakhulu xa kuthelekiswa neqela le-vinyl kwi-4-NS ngenxa yokudluliselwa kwe-electron kwi-interface ye-Ru-Ni, ebonisa ukusebenza okuthe ngqo kwe-NO bond kwiqela le-nitro.
In situ FT-IR yenzelwe ukubeka iliso kwinkqubo ye-catalytic ye-4-NS hydrogenation reaction kwiisampuli ze-catalyst (Umfanekiso 6).Kwi-nickel catalyst yokuqala (umzobo 6a), ukuhla okuncinci kuphela koxinzelelo lwe-nitro (1520 kunye ne-1351 cm-1) kunye ne-C = C (1595 cm-1) iibhendi zabonwa xa kudlula i-H2 kwi-12 min. ibonisa ukuba − I-Acction NO2 kunye ne-C=C zibuthathaka.Phambi kwe-monometallic Ru (Fig. 6b), i-ν(C=C) band (kwi-1591 cm–1) icutheka ngokukhawuleza phakathi kwe-0–12 min, ngelixa i-νs(NO2) kunye ne-νas(NO2) iibhendi zicuthwa ngamandla. .Okucothayo Oku kubonisa ukusetyenziswa okukhethiweyo kweqela le-vinyl ye-hydrogenation, ekhokelela ekubunjweni kwe-4-nitroethylbenzene (4-NE).Kwimeko ye-0.4 wt.I-% RuNi (SAA) (Fig. 6c), ibhendi ye-νs(NO2) (1347 cm–1) iyanyamalala ngokukhawuleza ngokungena kwe-hydrogen, ihamba nokubola ngokuthe ngcembe kwe-ν(N=O );ibhendi entsha egxile kwi-1629 cm-1 nayo yabonwa, ibalelwa kukushukuma kwe-NH.Ukongeza, ibhendi ye-ν(C=C) (1596 cm–1) ibonisa kuphela ukuhla okuncinci emva kwe-12 min.Olu tshintsho oluguquguqukayo luqinisekisa i-polarization kunye ne-hydrogenation ye-NO2 ukuya -NH2 ngo-0.4 wt% RuNi (SAA) ngokusekelwe kwi-chemoselectivity ekhethekileyo kwi-4-aminostyrene.Kwisampulu ye-2 wt.% RuNi (Fig. 6d), ukongeza kwimbonakalo yebhendi entsha kwi-1628 cm–1 echazwe ku-δ (NH), i-ν(C=C) ibhendi iyancipha kwaye iyanyamalala ngokunyuka kweqela le-nitro (1514). kunye ne-1348 cm-1).Oku kubonisa ukuba i-C = C kunye ne-NO2 isebenze ngokufanelekileyo ngenxa yobukho be-Ru-Ru kunye ne-Ru-Ni yamaziko e-interfacial interfacial, ngokulandelanayo, ehambelana nokuqulunqwa kwe-4-NE kunye ne-4-AE kwi-2 wt.% I-RuNi catalyst.
Kwisitu i-FT-IR imbonakalo ye-4-NS ye-hydrogenation phambi kwe-monometallic Ni, b monometallic Ru, c 0.4 wt% RuNi SAA, kunye ne-d 2 wt% i-RuNi kwi-H2 flow kwi-1700-1240 cm- Uluhlu 1 lwarekhodwa njenge igesi yokusabela emva kwe-0, 3, 6, 9 kunye ne-12 imizuzu, ngokulandelanayo.“au” ithetha iiyunithi ezingafanelekanga.Ukuhanjiswa kwamandla okunokwenzeka kunye nezakhiwo ezihambelanayo ezilungiselelwe i-C=C hydrogenation kunye NO-scission kwi-4-NS kwi-e Ni(111) kunye ne-f RuNi SAA (111) umphezulu.Ru – violet, Ni – green, C – orenji, O – obomvu, N – blue, H – white."iintengiso", "IS", "TS", kunye ne "FS" zimele imo ye-adsorption, imo yokuqala, imo yotshintsho, kunye nemo yokugqibela, ngokulandelelanayo.
Iindlela ezinokwenzeka ze-4-NS ukuguqulwa kwi-Ni (111) kunye ne-RuNi SAA (111), kubandakanywa i-C = C hydrogenation kunye ne-NO bond cleavage, ziphandwe ngokubala kwe-DFT ukucacisa ngakumbi indima ebalulekileyo ye-4-NS.Amacandelo e-interface ye-Ru-Ni yokuveliswa kweethagethi ze-4-AS.Kumhlaba we-Ni (111) (umzobo 6e), izithintelo zamandla ze-NO scission kunye ne-hydrogenation yamaqela e-vinyl kwinqanaba lokuqala yi-0.74 kunye ne-0.72 eV, ngokulandelanayo, ebonisa ukuba i-chemoselective hydrogenation yamaqela e-nitro kwi-4-HC engathandekiyo.yemonometallic nickel imiphezulu.Ngokuchasene noko, umqobo wamandla we-NO dissociation kuphela yi-0.46 eV ephezulu kune-RuNi SAA (111), ephantsi kakhulu kune-C = C bond hydrogenation (0.76 eV) (Fig. 6f).Oku kuqinisekisa ngokungathandabuzekiyo ukuba amaziko e-Ru-Ni interfacial anciphisa ngokufanelekileyo umqobo wamandla we-NO scission kumaqela e-nitro, ekhokelela ekunciphiseni okukhethiweyo kwe-thermodynamically yamaqela e-nitro xa kuthelekiswa namaqela e-C = C kumphezulu we-surfactant we-RuNi, ovumelana neziphumo zovavanyo.
Indlela yokusabela kunye nee-curves zamandla ezibalwayo ze-4-NS hydrogenation kwi-RuNi SAA zaphandwa ngokusekelwe kwizibalo ze-DFT (umzobo 7), kunye nokucwangciswa kwe-adsorption eneenkcukacha zamanyathelo aphambili kuboniswe kwi-Supplementary Fig. 41. Ukwandisa inkqubo yokubala, izithintelo zokuvelisa amandla kwiimolekyuli zamanzi zazingabandakanywa kwiizibalo.iimodeli zepleyiti9,17.Njengoko kubonisiwe kwifig.I-7, ii-molecule ze-4-NS ziqala ukuxutywa ngokuhambelana kwi-surfactant ye-RuNi, kunye ne-athomu ezimbini ze-O kwiqela le-nitro zibophelelwe kumaziko e-Ru-Ni interfacial (S0; inyathelo I).Emva koko, i-NO bond eqhotyoshelwe kwisayithi ye-Ru iphukile, ehamba kunye nokubunjwa kwe-nitroso intermediate (C8H7NO *) kwindawo ye-interface ye-Ru-Ni kunye ne-O * kwindawo engenanto ye-Ni (S0 → S1 nge-TS1; amandla umqobo: 0.46 eV, inyathelo lesibini ).I-O* radicals yenziwa i-hydrogenated yi-athom ye-H esebenzayo ukwenza iimolekyuli ze-H2O ezine-exotherm ye-0.99 eV (S1 → S2).Izithintelo zamandla kwi-hydrogenation ye-C8H7NO* ephakathi (iMizobo eyoNgezelelweyo ye-42 kunye ne-43) ibonisa ukuba ii-athom ze-H ezisebenzayo ezivela kwiindawo ezingenanto ze-Ru-Ni zikhetha ukuhlasela ii-athom ze-O ngaphezu kwe-athom ze-N, okukhokelela kwi-C8H7NOH * (S2 → S4; umqobo wamandla TS2: 0.84) eV, inyathelo III).Ii-athomu ze-N kwi-C8H7NOH* zaye zenziwa i-hydrogenated ukuze zenze i-C8H7NHOH* emva kokuwela umqobo we-1.03 eV (S4→S6; inyathelo IV), elilinyathelo elichazayo lokusabela kuyo yonke.Emva koko, ibhondi ye-N-OH kwi-C8H7NHOH* yaphulwa kwi-interface ye-Ru-Ni (S6 → S7; isithintelo samandla: 0.59 eV; isigaba V), emva koko i-OH* yahlanjululwa kwi-HO (S7 → S8; exotherm: 0.31 eV ) Emva koko, ii-athomu ze-N ze-Ru-Ni hollow sites kwi-C8H7NH * zongezwa nge-hydrogenated ukuze zenze i-C8H7NH2 * (4-AS) kunye nomqobo wamandla we-0.69 eV (S8 → S10; inyathelo VI).Ekugqibeleni, ii-molecule ze-4-AS kunye ne-HO zachithwa kwi-RuNi-PAA, kwaye i-catalyst yabuyela kwimeko yayo yokuqala (isinyathelo VII).Esi sakhiwo esikhethekileyo sokudibanisa phakathi kwe-athomu ye-Ru enye kunye ne-Ni substrates, ehamba kunye nefuthe le-synergistic ye-doping host kwi-RuNi SAA, iphumela kumsebenzi obalaseleyo kunye ne-chemoselectivity ye-4-NS hydrogenation.
Irayisi.4. Umzobo weSchematic wendlela yokuphendula i-hydrogenation ye-NS ukuya kwi-4-AS kwi-RuNi PAA surface.Ru – violet, Ni – green, C – orenji, O – obomvu, N – blue, H – white.I-inset ibonisa ukuhanjiswa kwamandla anokubakho kwe-4-NS hydrogenation kwi-RuNi SAA (111) indawo, ebalwa ngesiseko se-DFT."I-S0" imele imo yokuqala, kwaye "i-S1-S10" imele uthotho lweendawo zentengiso."TS" imele imo yotshintsho.Amanani kwiibrakethi amele izithintelo zamandla zamanyathelo aphambili, kwaye amanani aseleyo amele amandla e-adsorption of intermediates ahambelanayo.
Ngaloo ndlela, ii-catalysts ze-RuNi SAA zifunyenwe ngokusebenzisa i-electrosubstitution reactions phakathi kwe-RuCl3 kunye ne-Ni NPs efunyenwe kwi-LDH precursors.Xa kuthelekiswa ne-monometallic Ru, i-Ni kunye nezinye i-catalysts ezichazwe ngaphambili, i-RuNi SAA eyaphumelayo ibonise ukusebenza kakuhle kwe-catalytic ye-4-NS chemoselective hydrogenation (i-4-AS isivuno:> 99%; ixabiso le-TOF: 4293 h-1).Iimpawu ezidibeneyo ezibandakanya i-AC-HAADF-STEM, kwi-situ CO-DRIFTS, kunye ne-XAFS iqinisekisile ukuba ii-athomu ze-Ru zazingenakunyakaziswa kwi-Ni NPs kwinqanaba le-athomu enye nge-Ru-Ni bonds, ehamba kunye nokudluliselwa kwe-electron ukusuka ku-Ni ukuya ku-Ru.Kwi-situ XAFS, ii-experiments ze-FT-IR, kunye nezibalo ze-DFT zibonise ukuba i-interface ye-Ru-Ni ye-interface isebenza njengendawo yangaphakathi esebenzayo yokuvula okukhethiweyo kwe-NO bond kwiqela le-nitro;I-synergism phakathi kwe-Ru kunye neendawo ze-Ni ezingabamelwane ziququzelela ukusebenza okuphakathi kunye ne-hydrogenation, ngaloo ndlela iphucula kakhulu ukusebenza kakuhle kwe-catalytic.Lo msebenzi ubonelela ngokuqonda kubudlelwane phakathi kweesayithi ezisebenza kabini kunye nokuziphatha kwe-catalytic ye-SAA kwinqanaba le-atom, ihlahlela indlela yoyilo oluqiqileyo lwezinye iindlela ezimbini zokukhuthaza ukukhetha okunqwenelekayo.
Ama-reagents okuhlalutya asetyenziswe kuvavanyo lwathengwa kwi-Sigma Aldrich: Al2 (SO4) 3 18H2O, tartrate ye-sodium, CO (NH2) 2, NH4NO3, Ni (NO3) 2 6H2O, RuCl3, ethanol, 4-nitrostyrene (4- NS) , 4-aminostyrene, 4-nitroethylbenzene, 4-aminoethylbenzene kunye ne-nitrostyrene.Amanzi asulungekileyo asetyenziswa kuzo zonke iimvavanyo.
I-Hierarchical NiAl LDHs zadityaniswa njengezandulela ngokukhula kwindawo.Okokuqala, i-urea (3.36 g), i-Al2 (SO4) 3 · 18H2O (9.33 g) kunye ne-sodium tartrate (0.32 g) yachithwa emanzini adibeneyo (140 ml).Isisombululo esibangelwayo sidluliselwe kwi-autoclave ye-Teflon-coated kwaye ishushu kwi-170 ° C kwi-3 h.I-precipitate ebangelwayo ihlanjwe ngamanzi adibeneyo kwaye yomiswe kakuhle, emva koko i-calcined kwi-500 ° C (2 ° C min-1; 4 h) ukufumana i-amorphous Al2O3.Emva koko i-Al2O3 (0.2 g), i-Ni (NO3) 2 6H2O (5.8 g) kunye ne-NH4NO3 (9.6 g) yachithwa emanzini ahlambulukileyo (200 ml) kwaye i-pH yahlengahlengiswa kwi- ~ 6.5 ngokongeza i-1 mol l -1 amanzi ammonia..Ukumiswa kwadluliselwa kwi-flask kwaye kugcinwe kwi-90 ° C kwi-48 h ukufumana i-NiAl-LDH.Emva koko i-NiAl-LDH powder (0.3 g) yancitshiswa kumlambo we-H2 / N2 (10/90, v / v; 35 ml min-1) kwi-500 ° C kwi-4 h (izinga lokushisa: 2 ° C min -1 ).Ukulungiswa kweesampuli ze-nickel ye-monometallic (Ni / Al2O3) efakwe kwi-amorphous Al2O3.Iisampuli ze-bimetallic ezifakwe kwi-RuNi zenziwe nge-electrodisplacement method.Ngokuqhelekileyo, isampuli entsha ye-Ni / Al2O3 (0.2 g) yachithwa kwi-30 ml yamanzi ahlambulukileyo, emva koko isisombululo se-RuCl3 (0.07 mmol l-1) yongezwa ngokukhawuleza kwaye yaxutywa ngamandla kwimizuzu engama-60 phantsi kokhuseleko lwe-N2. .I-precipitate ebangelwa yi-centrifuged, ihlanjwe ngamanzi ahlambulukileyo, kwaye yomiswe kwi-oven vacuum kwi-50 ° C nge-24 h, ukufumana isampuli equkethe i-0.1% RuNi.Ngaphambi kovavanyo lwe-catalytic, iisampuli ezisandul 'ukwenziwa zancitshiswa ngaphambili kwi-H2 / N2 flow (10/90, v/v) kwi-300 ° C (izinga lokufudumala: 2 ° C min-1) kwi-1 h, kwaye emva koko ishushu ngaphakathi. N2 Ipholile kwiqondo lobushushu begumbi.Ukufumana ireferensi: iisampuli ezinomxholo we-Ru / Al2O3 we-0.4% kunye ne-2% ngobunzima, kunye nomxholo we-Ru wangempela we-0.36% ngobunzima kunye ne-2.3% ngobunzima, zilungiswe yimvula ngemvula kwaye zishushu kwi-300 ° C (ukusetyenziswa kwe-H2 / I-N2 : 10/90, v/v, izinga lokufudumeza: 2 °C min–1) iiyure ezi-3.
Uvavanyo lwe-X-ray diffraction (XRD) luye lwaqhutywa kwi-Bruker DAVINCI D8 ADVANCE diffractometer enomthombo wemitha ye-Cu Kα (40 kV kunye ne-40 mA).I-Shimadzu ICPS-7500 Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) yasetyenziselwa ukumisela ubuninzi bokwenene bezinto kwiisampuli ezahlukeneyo.Imifanekiso ye-electron microscopy (SEM) yokuskena yafotwa kusetyenziswa imakroskopu ye-electron yeZeiss Supra 55.Izilingo ze-N2 ze-adsorption-desorption zenziwa kwisixhobo se-Micromeritics ASAP 2020 kunye nommandla othile womhlaba ubalwa kusetyenziswa indlela ye-Brunauer-Emmett-Teller (BET) ye-multipoint.Iimpawu zokuhanjiswa kwe-electron microscopy (TEM) zenziwa kwi-JEOL JEM-2010 ye-high-resolution electron microscope.I-Angle Aberration eLungileyo iScanning Transmission Electron Microscope Dark Field (AC-HAADF) – STEM ene-FEI Titan Cube Themis G2 300 ene-spherical aberration corrector kunye ne-Energy Dispersive X-ray Spectroscopy (EDS) kunye neJEOL JEM-ARM200F isixhobo sokulinganisa imephu ye-EDS .Isakhiwo esihle i-X-ray yokufunxa i-spectroscopy (XAFS) kwindawo ye-K-edge ye-Ru kunye ne-Ni K-edge yalinganiswa kwiitshaneli ze-1W1B kunye ne-1W2B ye-Beijing Synchrotron Radiation Facility (BSRF) yeZiko leFiziksi yaMandla aPhezulu (IHEP), eChina. .IAkhademi yeSayensi (KAN).I-Pulsed CO chemisorption kunye neqondo lokushisa-programmed hydrogen desorption (H2-TPD) iimvavanyo zenziwa kwi-Micromeritics Autochem II 2920 isixhobo usebenzisa i-thermal conductivity detector (TCD).Imifuniselo ye-in situ DRIFTS kunye ne-FT-IR yaqhutywa kwi-Bruker TENSOR II ye-infrared spectrometer exhotyiswe nge-modified in situ reaction cell kunye ne-MCT detector enovakalelo kakhulu.Iindlela zokulinganisa ezineenkcukacha zichazwe kwiiNkcukacha ezoNgezelelweyo.
Okokuqala, i-substrate (4-NS, 1 mmol), i-solvent (i-ethanol, i-8 ml) kunye ne-catalyst (0.02 g) yongezwa ngokucophelela kwi-autoclave ye-stainless steel 25 ml.I-reactor yahlanjululwa ngokupheleleyo nge-2.0 MPa (> 99.999%) i-hydrogen 5 amaxesha, kwaye emva koko icinezelwe kwaye itywinwe kwi-1.0 MPa nge-H2.Ukuphendula kwenziwa kwi-60 ° C kwisantya esichukumisayo esingaguqukiyo se-700 rpm.Emva kokuphendula, iimveliso ezifunyenweyo zichongiwe yi-GC-MS kwaye zihlalutyelwe ngokobuninzi kusetyenziswa inkqubo ye-chromatography ye-Shimadzu GC-2014C exhotywe ngekholomu ye-capillary ye-GSBP-INOWAX (30 m × 0.25 mm × 0.25 mm) kunye ne-FID detector.Ukuguqulwa kwe-4-nitrostyrene kunye nokukhetha kwemveliso kuye kwamiselwa ngolu hlobo lulandelayo:
Ixabiso le-turnover frequency (TOF) libalwe njenge-mol 4-NS eguqulelwe kwindawo nganye yentsimbi ye-mol ngeyure (mol4-NS mol-1 h-1) ngokusekelwe kuguqulo oluphantsi lwe-4-NS (~ 15%).Ngokuphathelele inani le-Ru-nodes, i-Ru-Ni i-interface nodes kunye nenani elipheleleyo le-athomu yesinyithi.Uvavanyo lokuphinda lusetyenziswe, i-catalyst yaqokelelwa nge-centrifugation emva kokuphendula, ihlanjwe kathathu nge-ethanol, ize iphinde ifakwe kwi-autoclave kumjikelezo olandelayo we-catalytic.
Zonke izibalo ze-density functional theory (DFT) zenziwa kusetyenziswa i-Vienna ab initio simulation package (VASP 5.4.1).I-Generalized Gradient Approximation (GGA) umsebenzi wePBE usetyenziselwa ukuchaza utshintshiselwano lwe-electron kunye neemeko zokulungelelanisa.Indlela yeProjector Augmented Wave (PAW) isetyenziselwa ukuchaza intsebenziswano phakathi kweenuclei zeathom kunye neeelectron.Indlela ye-Grimm DFT-D3 ichaza umphumo we-van der Waals ukusebenzisana phakathi kwe-substrate kunye ne-interface.Ukubalwa kweZithintelo zaMandla ngokuNyula iibhendi ze-Elastic kunye ne-Image Boost (CI-NEB) kunye ne-Dimer Methods.Uhlalutyo lwama-frequency oscillations lwenziwa, luqinisekisa ubukho be-frequency enye kuphela yokucinga kwimeko nganye yenguqu (Amanani abongezelelweyo 44-51).Ubalo oluthe kratya luchazwe kulwazi olongezelelweyo.
Idatha ephambili exhasa izicwangciso kweli nqaku inikwe kwiifayile zedatha yomthombo.Enye idatha efanelekileyo kolu phononongo iyafumaneka kubabhali abachaphazelekayo ngesicelo esifanelekileyo.Eli nqaku libonelela ngedatha yokuqala.
I-Korma A. kunye ne-Serna P. I-Chemoselective hydrogenation ye-nitro compounds kunye ne-catalysts zegolide ezixhaswayo.Inzululwazi 313, 332-334 (2006).
Formenti D., Ferretti F., Sharnagle FK kunye noBeller M. Ukunciphisa i-nitro compounds usebenzisa i-3d base base catalysts.Ikhemikhali.119, 2611–2680 (2019).
Tan, Y. et al.I-Au25 nanoclusters exhaswa kwi-ZnAl hydrotalcite njenge-precatalysts ye-chemoselective hydrogenation ye-3-nitrostyrene.Angie.Ikhemikhali.yangaphakathi Ed.56, 1-6 (2017).
UZhang L, uZhou M, uWang A, kunye noZhang T. I-hydrogenation ekhethiweyo kwii-catalysts zetsimbi ezixhaswayo: ukusuka kwi-nanoparticles ukuya kwi-athomu nganye.Ikhemikhali.120, 683–733 (2020).
Sun, K. et al.I-Monoatomic rhodium catalysts efakwe kwi-zeolite: Ukuveliswa kwe-hydrogen esebenzayo kunye ne-selective cascade hydrogenation ye-nitroaromatic compounds.Angie.Ikhemikhali.yangaphakathi Ed.58. 18570-18576 (2019).
Tian, ​​S.okqhubekayo.I-Diatomic Pt heterogeneous catalyst enentsebenzo ebalaseleyo ye-catalytic yokukhetha i-hydrogenation kunye ne-epoxidation.Unxibelelwano lwesizwe.12, 3181 (2021).
Wang, Yu.okqhubekayo.I-Chemoselective hydrogenation ye-nitroarenes kwi-iron nanosized (III)-OH-platinum interfaces.Angie.Ikhemikhali.yangaphakathi Ed.59, 12736-12740 (2020).
Wei, H. et al.I-FeOx ixhase i-platinum monatomic kunye ne-pseudomonoatomic catalysts ye-chemoselective hydrogenation ye-functionalized nitroaromatic compounds.Unxibelelwano lwesizwe.5, 5634 (2014).
Khan, A. et al.Ukwahlula ii-athomu ze-Pt ezilandelelanayo kunye nokuqulunqwa kwe-Pt-Zn intermetallic nanoparticles ukuze kulungiswe ukhetho lwe-4-nitrophenylacetylene hydrogenation.Unxibelelwano lwesizwe.10, 3787 (2019).
Wang, K. et al.Ujongo kubungakanani obungaqhelekanga bokuxhomekeka kwii-monatomic Pt catalysts ezixhaswa kwi-CeO2.IKhemistri 6, 752–765 (2020).
Feng Yu et al.Kwimfuno ye-ultra-selective hydrogenation system usebenzisa iPd-Cd nanocubes ezicudisiweyo.IJam.Ikhemikhali.uluntu.142, 962–972 (2020).
Fu, J. et al.Iziphumo ze-Synergistic zokuphucula i-catalysis kwi-double monatomic catalysts.IsiCatalan SAU.11, 1952-1961 (2021).
Liu, L. et al.Ukumisela ukuguquka kwee-athomu zetsimbi enye kunye ne-nanoclusters phantsi kweemeko zokusabela: zeziphi iindawo ezisebenzayo ze-catalytic?IsiCatalan SAU.9, 10626–10639 (2019).
Yang, N. et al.I-Amorphous / crystalline heterogeneous palladium nanosheets: i-synthesis yembiza enye kunye nempendulo ekhethiweyo ye-hydrogenation.I-alma mater ephucukileyo.30, 1803234 (2018).
Gao, R. et al.Ukuqhawula urhwebo phakathi kokukhetha kunye nomsebenzi we-nickel-based hydrogenation catalysts ngokuguqula iziphumo zesteric kunye namaziko e-d-band.Inzululwazi ephucukileyo.6, 1900054 (2019).
Lee, M. et al.Umthombo osebenzayo we-Co-NC catalysts ye-chemoselective hydrogenation ye-nitroaromatic compounds.IsiCatalan SAU.11, 3026-3039 (2021).