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Hōʻike i kahi carousel o ʻekolu paheʻe i ka manawa hoʻokahi.E hoʻohana i nā pihi Mua a me Next no ka neʻe ʻana i ʻekolu paheʻe i ka manawa, a i ʻole e hoʻohana i nā pihi paheʻe ma ka hopena e neʻe i ʻekolu mau paheʻe i ka manawa.
ʻO ka hoʻolālā a me ka hoʻomohala ʻana o nā catalysts hana kiʻekiʻe ua loaʻa ka nānā nui ʻana i nā hopena hydrogenation koho akā mau nō ka paʻakikī nui.Maʻaneʻi ke hōʻike nei mākou i kahi hui RuNi monatomic (SAA) kahi i hoʻopaʻa ʻia ai nā ʻātoma Ru pākahi ma ka ʻili o Ni nanoparticles ma o ka hoʻohui ʻana ʻo Ru-Ni, i hui pū ʻia me kahi hoʻololi electron mai lalo o Ni a i Ru.I ko mākou ʻike, ʻo ka catalyst maikaʻi loa 0.4% RuNi SAA i ka manawa like i hōʻike i ka hana kiʻekiʻe (TOF waiwai: 4293 h-1) a me ka chemoselectivity no ka hydrogenation koho o 4-nitrostyrene i 4-aminostyrene (hua:> 99%), ka pae kiʻekiʻe loa e hoʻohālikelike ʻia me nā catalysts heterogeneous i ʻike ʻia.Hōʻike nā hoʻokolohua in situ a me nā helu kuhi ʻana i nā kahua kikowaena Ru-Ni, ma ke ʻano he kahua hana kūloko, e paipai i ka haki ʻana i nā mea paʻa NO me kahi pale ikehu haʻahaʻa o 0.28 eV.Eia kekahi, ʻoi aku ka maikaʻi o ka synergistic Ru-Ni catalysis i ka hoʻokumu ʻana o nā mea waena (C8H7NO * a me C8H7NOH *) a hoʻolalelale i ka pae hoʻoholo helu (hydrogenation o C8H7NOH *).
Functionalized aromatic amines, koʻikoʻi kūkulu hale o nā kemika maikaʻi, he koʻikoʻi nā noi ʻoihana i ka hana ʻana i nā lāʻau lapaʻau, agrochemical, pigments a me nā polymers1,2,3.ʻO ka hydrogenation catalytic o nā pūhui nitroaromatic hiki ke loaʻa ma luna o nā catalysts heterogeneous ua hoʻokipa nui ʻia ma ke ʻano he ʻano hoʻonaninani a hiki ke hana hou ʻia no ka synthesis o nā amine me ka waiwai hoʻohui 4,5,6,7.Eia nō naʻe, ʻo ka hoʻemi chemoselective o nā pūʻulu -NO2 ʻoiai ka mālama ʻana i nā pūʻulu hoʻēmi ʻē aʻe e like me nā alkenes, alkynes, halogens, a i ʻole ketones he mea makemake nui akā paʻakikī ka hana8,9,10,11.No laila, makemake nui ʻia ka hoʻohana pono ʻana o nā catalysts heterogeneous no ka hōʻemi kikoʻī o nā pūʻulu -NO2 me ka ʻole o ka hoʻopili ʻana i nā mea hoʻopaʻa hoʻēmi ʻē aʻe.Ua noiʻi ʻia ka nui o nā catalysts noble-metal-free no ka hoʻoheheʻe ʻana i ka hydrogenation o nā nitroarenes, akā naʻe, ʻaʻole nā ​​​​kūlana hoʻokō koʻikoʻi i kā lākou noi ākea15,16.ʻOiai ʻo nā catalysts metala hanohano (e like me Ru17, Pt18, 19, 20 a i ʻole Pd21, 22, 23) e hana ana ma lalo o nā kūlana hoʻonā haʻahaʻa, maʻamau lākou e loaʻa i ke kumu kūʻai kiʻekiʻe, suboptimal selectivity, a me ka hoʻohana haʻahaʻa atom.No laila, ʻo ka loaʻa ʻana o nā catalysts ikaika loa a me ka chemoselective ma o ka hoʻolālā kūpono a me ka hoʻoponopono maikaʻi ʻana o ka hoʻolālā maikaʻi e mau ana i kahi luʻi nui24,25,26.
Loaʻa i nā mea hoʻoheheʻe Monatomic Alloy (SAA) ka ʻoi aku ka maikaʻi o ka metala hanohano, ka geometric kūikawā a me ka hoʻolālā uila, hāʻawi i nā wahi hana kū hoʻokahi, a hāʻawi i ka hana catalytic koʻikoʻi ma ka uhai ʻana i ke ʻano linear scaling behavior27,28,29,30,31.Hiki i nā ʻātoma hoʻokahi doped a me nā ʻātoma metala hoʻokipa ma SAA ke lilo i mau pūnaewele hana ʻelua, e hoʻomaʻamaʻa i ka hoʻāla ʻana o nā substrates he nui a i ʻole e ʻae i nā ʻanuʻu ʻano like ʻole e kū i nā pae like ʻole32,33,34.Eia kekahi, hiki i nā hui heterometallic ma waena o nā ʻātoma metala haumia kaʻawale a me nā metala hoʻokipa hiki ke alakaʻi i nā hopena synergistic idiosyncratic, ʻoiai ʻo ka hoʻomaopopo ʻana i kēlā mau hopena synergistic ma waena o ʻelua mau pae o nā pae metala ma ka pae atomic e mau ana ka controversial35,36,37,38.No ka hydrogenation o nā nitroarenes i hana ʻia, pono e hoʻolālā ʻia nā ʻōnaehana uila a me nā geometric o nā wahi hana i ke ʻano e wikiwiki ai ka hoʻāla ʻana o nā pūʻulu nitro wale nō.E like me ka rula, electron-deficient nitro pūʻulu ua predominantly adsorbed ma ka nucleophilic māhele o ka catalyst ili, oiai ma ka hope hydrogenation ala, cooperative catalysis o nā wahi hana e pili ana e pāʻani koʻikoʻi i ka hoomalu ana reactivity a me chemoselectivity4,25.ʻO kēia ka mea i koi iā mākou e ʻimi i nā mea hoʻoheheʻe SAA ma ke ʻano he moho hoʻohiki no ka hoʻomaikaʻi ʻana i ka pono catalytic o ka chemoselective hydrogenation o nā pūhui nitroaromatic, a me ka hoʻomaʻamaʻa hou ʻana i ka pilina ma waena o ka hoʻolālā kahua hana a me ka hana catalytic scale atomic.
Maʻaneʻi, ua hoʻomākaukau ʻia nā catalysts i hoʻokumu ʻia i nā ʻāpana monatomic RuNi ma muli o kahi ʻano hana synthetic ʻelua, me ka hoʻololi ʻana o ka structural-topological o kahi layered double hydroxide (LDH) i ukali ʻia e ka mālama electro-displacement.Hōʻike ʻo RuNi SAA i ka maikaʻi catalytic maikaʻi loa (> 99% hua) no ka hydrogenation chemoselective o 4-nitrostyrene i 4-aminostyrene me ke alapine huli (TOF) a hiki i ~4300 mol-mol Ru-1 h-1, ʻo ia ka mea kiʻekiʻe loa. pae ma waena o nā catalysts heterogeneous i hoʻopaʻa inoa ʻia ma lalo o nā kūlana hopena like.Ua hōʻike ʻia ka microscopy electron a me ka spectroscopic characterization ua hoʻopuehu ʻia nā mana Ru i kaʻawale ma luna o ka ʻili o Ni nanoparticles (~ 8 nm), e hana ana i kahi hoʻohui Ru-Ni paʻa, e hopena i nā pae Ru maikaʻi ʻole (Ruδ-) ma muli o ka hoʻoili electron mai lalo o ka Ni a i Ru .Ma kahi FT-IR, nā haʻawina XAFS a me ka helu ʻana i ke kumumanaʻo hana (DFT) i hōʻoia i nā pūnaewele ma ka interface Ru-Ni e like me nā pae hana kūloko e hoʻomaʻamaʻa i ka nitro.ʻOkoʻa ka adsorption hoʻāla ʻia (0.46 eV) me ka mea hoʻoheheʻe nickel monometallic.(0.74 eV).Eia kekahi, hiki ke hoʻokaʻawale hydrogen i nā kūlana Ni e pili ana, a ukali ʻia e ka hydrogenation o nā waena (C8H7NO* a me C8H7NOH*) ma nā kūlana Ruδ.ʻO ka hopena synergistic o ke kākoʻo doping i ka RuNi SAA catalyst e loaʻa i ka hana hydrogenation nitroarenes a me ke koho, hiki ke hoʻonui ʻia i nā catalysts metala hanohano ʻē aʻe i hoʻohana ʻia i nā ʻano hoʻonaninani.
Ma muli o ka hoʻololi ʻana o ka topology structural o layered double hydroxide (LDH) precursors, ua hoʻomākaukau mākou i ka monometallic Ni i waiho ʻia ma nā substrates Al2O3 amorphous.Ma hope o kēlā, ua hoʻonohonoho ponoʻia kahi pūʻulu o RuNi / Al2O3 bimetallic laʻana me nā maʻiʻo Ru likeʻole (0.1-2 wt %) me ka electrodisplacement e waiho i nā Ru atoms ma kaʻili o Ni nanoparticles (NPs) (Fig. 1a).Inductively hui pūʻia plasma atomic emission spectrometry (ICP-AES) ana maopopo haawi i ka elemental haku mele o Ru a me Ni i loko o keia mau laʻana (Supplementary Table 1), kahi kokoke i ka theoretical feedstock hoouka.Hōʻike maopopo nā kiʻi SEM (Supplementary Figure 1) a me BET (Supplementary Figures 2-9 a me Supplementary Table 1) i ke ʻano o ka morphological a me kahi kikoʻī kikoʻī o nā kumu RuNi / Al2O3 ʻaʻole i loaʻa nā loli i ka wā o ka mālama electrochemical.- ke kaʻina hana o ka neʻe ʻana.Hōʻike ke ʻano X-ray (Fig. 1b) i ke ʻano o nā hiʻohiʻona hiʻohiʻona ma 2θ 44.3°, 51.6°, a me 76.1°, e hōʻike ana i nā pae (111), (200), a me (220) o ka Ni maʻamau (JCPDS 004-0850). ).ʻO ka mea nui, ʻaʻole hōʻike ka RuNi i nā hiʻohiʻona o ka Ru metala a i ʻole oxidized Ru, e hōʻike ana i kahi pālahalaha kiʻekiʻe o nā ʻano Ru.Hōʻike ʻia nā ana o ka microscopy electron transmission (TEM) o nā mea hoʻohālike monometallic Ni a me RuNi (Fig. 1c1-c8) ua hoʻopuehu maikaʻi ʻia nā nanoparticles nickel a immobilized ma kahi kākoʻo Al2O3 amorphous me nā ʻāpana like like (7.7-8.3 nm).Hōʻike nā kiʻi HRTEM (Fig. 1d1-d8) i kahi manawa lattice like ʻole ma kahi o 0.203 nm ma nā ʻāpana Ni a me RuNi, e pili ana i nā mokulele Ni (111), akā naʻe, ʻaʻole i loaʻa nā kihi lattice o nā ʻāpana Ru.Hōʻike kēia i ka hoʻopuehu nui ʻana o nā ʻātoma Ru ma ka ʻili hoʻohālike a ʻaʻole pili i ka wā lattice Ni.I kēia manawa, ua hoʻohui ʻia ʻo 2 wt% Ru / Al2O3 e ke ʻano deposition-deposition ma ke ʻano he mana, kahi i hoʻokaʻawale like ʻia ai nā pūʻulu Ru ma ka ʻili o ka substrate Al2O3 (Supplementary Fig. 10-12).
a Papahana o ke ala synthesis no RuNi/Al2O3 laana, b X-ray diffraction patterns o Ni/Al2O3 a me kekahi mau la'ana RuNi/Al2O3.c1−c8 TEM a me d1−d8 HRTEM grating kii me ka mahele nui o na mea pakahi o ka monometallic Ni, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0, 8% wt., 1 wt.Kiʻi ʻoniʻoni.% a me 2 wt.% RuNi.“au” ʻo ia hoʻi nā ʻāpana kūʻokoʻa.
Ua aʻo ʻia ka hana catalytic o nā laʻana RuNi e ka chemoselective hydrogenation o 4-nitrostyrene (4-NS) i 4-aminostyrene (4-AS).ʻO ka hoʻololi ʻana o 4-NS ma ka substrate Al2O3 maʻemaʻe he 0.6% wale nō ma hope o 3 mau hola (Paʻi ʻĀpana 2), e hōʻike ana i ka hopena catalytic liʻiliʻi o Al2O3.E like me ka hoike ana ma ka fig.2a, ua hōʻike ka nickel catalyst kumu i ka haʻahaʻa haʻahaʻa haʻahaʻa me ka hoʻololi ʻana o 4-NS o 7.1% ma hope o 3 mau hola, ʻoiai 100% hiki ke hoʻokō ʻia ma ke alo o ka monometallic Ru catalyst ma lalo o nā kūlana like.Ua hōʻike ʻia nā catalysts RuNi a pau i ka hoʻonui nui ʻana i ka hana hydrogenation (hoʻololi: ~ 100%, 3 h) i hoʻohālikelike ʻia i nā mea hoʻohālike monometallic, a ua hoʻopili maikaʻi ʻia ka helu hopena me ka ʻike Ru.'O ia ho'i, he hana ko'iko'i nā 'āpana Ru i ka hana hydrogenation.ʻO ka mea e mahalo ai, ʻokoʻa ka koho huahana (Fig. 2b) ma muli o ka catalyst.No ka mea hoʻoheheʻe nickel maʻemaʻe liʻiliʻi, ʻo ka huahana nui ʻo 4-nitroethylbenzene (4-NE) (selectivity: 83.6%) a ʻo ka koho o 4-AC he 11.3%.I ka hihia o ka monometallic Ru, ʻoi aku ka maʻalahi o ka paʻa C=C ma 4-NS i ka hydrogenation ma mua o -NO2, e alakaʻi ana i ka hoʻokumu ʻana o 4-nitroethylbenzene (4-NE) a i ʻole 4-aminoethylbenzene (4-AE);ʻO ka koho o 4-AC he 15.7% wale nō.ʻO ka mea kupanaha, ua hōʻike ʻo RuNi catalysts me kahi mea haʻahaʻa Ru (0.1-0.4 wt%) i ke koho maikaʻi loa (> 99%) i ka 4-aminostyrene (4-AS), e hōʻike ana he NO2 a ʻaʻole vinyl, he chemoselective kūʻokoʻa.Ke ʻoi aku ka nui o ka maʻiʻo o Ru ma mua o 0.6 wt.%, ua emi loa ka koho o 4-AS me ka hoʻonui ʻana i ka hoʻouka ʻana o Ru, aʻo ke koho ʻana o 4-AE ma kahi.No ka catalyst i loaʻa ka 2 wt% RuNi, ua hoʻohāinu nui ʻia nā hui nitro a me vinyl me kahi koho kiʻekiʻe i 4-AE o 98%.No ke aʻo ʻana i ka hopena o ka mokuʻāina hoʻopuehu Ru ma ka hopena catalytic, 0.4 wt% Ru / Al2O3 nā laʻana i hoʻomākaukau ʻia (Nā Kiʻi Hoʻohui 10, 13 a me 14) kahi i hoʻopuehu nui ʻia ai nā ʻāpana Ru e like me nā ʻātoma pākahi i ukali ʻia e kekahi mau pūʻulu Ru.(quasi-atomic Ru).Hōʻike ka hana catalytic (Supplementary Table 2) i ka 0.4 wt% Ru / Al2O3 e hoʻomaikaʻi i ka koho 4-AS (67.5%) i hoʻohālikelike ʻia me ka 2 wt% Ru / Al2O3 hāpana, akā haʻahaʻa loa ka hana (hoʻololi: 12.9).%;3 hola).Ma muli o ka huina helu o nā pae metala ma ka ʻili i hoʻoholo ʻia e nā ana chemisorption pulsed CO, ua loaʻa ke alapine turnover (TOFmetal) o ka catalyst RuNi ma ka hoʻololi haʻahaʻa 4-NS (Supplementary Fig. 15), e hōʻike ana i kahi ʻano mua e hoʻonui. a laila e emi iho me ka hoʻonui ʻana i ka hoʻouka ʻana o Ru (Hoʻohui Fig. 16).Hōʻike kēia ʻaʻole hana nā pūnaewele metala āpau ma ke ʻano he mau wahi hana maoli no nā catalysts RuNi.Eia kekahi, ua helu ʻia ka TOF o ka mea hoʻoheheʻe RuNi mai nā pūnaewele Ru e hōʻike hou i kāna hana catalytic intrinsic (Fig. 2c).Ke piʻi nei ka ʻike o ka Ru mai ka 0.1 wt.% a hiki i ka 0.4 wt.% RuNi catalysts hōʻike kokoke mau TOF waiwai ​​(4271–4293 h–1), e hōʻike ana i ka localization o Ru particles in atomic dispersion (me ka hoʻokumu ʻana o RuNi SAA).) a lawelawe ʻo ia ma ke ʻano he kahua hana nui.Eia naʻe, me ka hoʻonui hou ʻana i ka hoʻouka ʻana o Ru (i loko o 0.6-2 wt%), ua emi nui ka TOF waiwai, e hōʻike ana i ka hoʻololi ʻana i ke ʻano intrinsic o ke kikowaena hana (mai ka hoʻopuehu atomika i Ru nanoclusters).Eia kekahi, i ko mākou ʻike, ʻo ka TOF o ka 0.4 wt% RuNi (SAA) catalyst aia ma ka pae kiʻekiʻe loa ma waena o nā mea hoʻoheheʻe metala i hōʻike mua ʻia ma lalo o nā kūlana hoʻohālikelike like (Supplementary Table 3), e hōʻike hou ana i nā alloys RuNi monoatomic e hāʻawi i nā waiwai catalytic maikaʻi loa.makaʻala.Hōʻike ka helu 17 hou i ka hana catalytic o ka 0.4 wt% RuNi (SAA) catalyst ma nā ʻano paʻi a me nā mahana o H2, kahi i hoʻohana ʻia ai ke kaomi H2 o 1 MPa a me ka mahana o ka hopena o 60 °C ma ke ʻano he hopena hopena maikaʻi loa.laʻana i loaʻa iā RuNi 0.4 wt.% (Fig. 2d), a ʻaʻohe emi nui o ka hana a me ka hua i ʻike ʻia ma luna o ʻelima mau pōʻai.X-ray a me TEM kiʻi o ka 0.4 wt% RuNi catalyst hoʻohana ma hope o 5 pōʻaiapuni (Supplementary Figures 18 a me 19) i hōʻike 'aʻole nui hoʻololi i loko o ke aniani hale, e hōʻike ana i ka kiʻekiʻe paʻa o ka koho hydrogenation hopena.Eia kekahi, hāʻawi ka 0.4 wt% RuNi (SAA) catalyst i nā hua maikaʻi loa o nā amine no ka chemoselective hydrogenation o nā pūhui nitroaromatic ʻē aʻe i loaʻa nā halogens, aldehydes, a me nā pūʻulu hydroxyl (Supplementary Table 4), e hōʻike ana i kona pono kūpono.
a Catalytic hoʻololi a me ka b puʻunaue o 4-nitrostyrene hydrogenation huahana ma ke alo o monometallic Ni, Ru, a me RuNi catalysts me ka likeʻole Ru maʻiʻo (0.1-2 wt %), c i ka catalytic dynamic laulā, Turnover frequency (TOF) ma RuNi catalysts c pili ana i ka Ru no ka mole.d E ho'āʻo no ka hiki ke hoʻohana hou i ka 0.4 wt.% RuNi catalyst no nā pōʻai catalytic ʻelima.Hoʻokumu ʻia ka ln (C0/C) i ka manawa pane o ka hydrogenation o e-nitrobenzene a me f-styrene me ka hui ʻana o ka nitrobenzene a me ka styrene (1:1).Nā kūlana hana: 1 mmol reagent, 8 ml solvent (ethanol), 0.02 g catalyst, 1 MPa H2, 60°C, 3 hola.Ua wehewehe ʻia nā pahu kuhi e like me ka deviation maʻamau o ʻekolu replicate.
No ka noiʻi hou ʻana i ka ʻokoʻa chemoselective nui, ua hoʻokō ʻia ka hydrogenation o kahi hui ʻana o styrene a me nitrobenzene (1: 1) i mua o nā catalysts monometallic Ni, Ru, 0.4 wt% RuNi, a me 2 wt% RuNi, kēlā me kēia (Hoʻohui Fig. .20).ʻOiai ua kūlike ka chemoselectivity o ka hydrogenation o nā pūʻulu hana, ʻoiaʻiʻo, aia kekahi mau ʻokoʻa i ke koho o ka hydrogenation intramolecular a me intermolecular hydrogenation ma muli o nā hopena allosteric molecular.E like me ka hoike ana ma ka fig.2e,f, ke kaha ln(C0/C) me ka manawa pane e haawi mai i ka laina pololei mai ke kumu mai, e hoike ana he nitrobenzene a me ka styrene he pseudo-first command reactions.Ua hōʻike nā mea hoʻoheheʻe nickel monometallic i nā haʻahaʻa haʻahaʻa haʻahaʻa loa no ka p-nitrobenzene (0.03 h-1) a me ka styrene (0.05 h-1).ʻO ka mea nui, ua hoʻokō ʻia kahi hana styrene hydrogenation maikaʻi loa (rate mau: 0.89 h-1) ma ka Ru monometallic catalyst, ʻoi aku ka kiʻekiʻe ma mua o ka hana hydrogenation nitrobenzene (rate mau: 0.18 h-1).I ka hihia o kahi catalyst i loaʻa iā RuNi(SAA) 0.4 wt.ʻOi aku ka maikaʻi o ka % nitrobenzene hydrogenation ma mua o ka styrene hydrogenation (rate mau: 1.90 h-1 vs. 0.04 h-1), e hōʻike ana i kahi makemake no ka hui -NO2.ma luna o C hydrogenation = paʻa C. No ka mea hoʻoheheʻe me 2 wt.% RuNi, ua emi iho ka nui o ka hydrogenation o nitrobenzene (1.65 h-1) i ka 0.4 wt.% RuNi (akā, ʻoi aku ka kiʻekiʻe ma mua o ka mono-metal catalyst), ʻoiai ka nui o ka hydrogenation rate o ka styrene i piʻi nui loa (rate mau: 0.68).h−1).Hōʻike pū kēia me ka hopena synergistic ma waena o Ni a me Ru, ua hoʻonui nui ʻia ka hana catalytic a me ka chemoselectivity i nā hui -NO2 i hoʻohālikelike ʻia me RuNi SAA.
No ka ʻike maka ʻana i nā mokuʻāina hoʻopuehu o nā pūhui Ru a me Ni, ua hana ʻia kahi ʻano kiʻi e hoʻohana ana i ke apo kiʻekiʻe kiʻekiʻe ʻeleʻele scanning electron microscopy me ka hoʻoponopono aberration (AC-HAADF-STEM) a me ka palapala ʻana i nā mea e ka ikehu dispersive spectroscopy (EDS).ʻO ka palapala ʻāina EMF elemental o ka hāpana me 0.4 wt% RuNi maʻiʻo (Fig. 3a, b) e hōʻike ana ua hoʻopuehu nui ʻia ʻo Ru ma nā nanoparticles nickel, akā ʻaʻole ma ka substrate Al2O3, ke kiʻi AC-HAADF-STEM pili (Fig. 3c) hōʻike, Ua hiki ke ike i ka ili o Ni NPs he nui olinolino o ka atomic nui o Ru atoms (i kaha 'ia e ka uliuli pua), oiai aole hui a me Ru nanoparticles i malamaia.Fig. 3d), e hōʻike ana i ka hoʻokumu ʻana o nā huila RuNi monatomic.No kahi laʻana i loaʻa iā RuNi 0.6 wt.% (Fig. 3e), hoʻokahi Ru atoms a me kahi hapa nui o Ru particles i nānā ʻia ma Ni NPs, e hōʻike ana i kahi hōʻuluʻulu liʻiliʻi o Ru atoms ma muli o ka hoʻonui ʻana i ka ukana.I ka hihia o kahi laʻana me 2 wt% RuNi maʻiʻo, nui nā pūʻulu Ru nui ma Ni NPs i loaʻa i ke kiʻi HAADF-STEM (Fig 3f) a me EDS elemental mapping (Supplementary Fig. 21), e hōʻike ana i kahi hōʻiliʻili nui o Ru. .
he kiʻi HAADF-STEM, b kiʻi palapala palapala EDS like, c kiʻi AC-HAADF-STEM kiʻekiʻe, d kiʻi STEM i hoʻonui ʻia a me ka hāʻawi ʻana i ka ikaika o ka hāpana 0.4 wt% RuNi.(e, f) AC–HAADF–STEM kiʻi o nā laʻana i loaʻa ka 0.6 wt.% RuNi a me 2 wt.% RuNi, pakahi.
Ke hoʻohālikelikeʻia me Ni / Al2O3 a me Ru / Al2O3 laʻana, DRIFTS spectra o CO adsorption in situ ua hanaʻia (Fig. 4a) e aʻo hou i nā kiko'ī kiko'ī o nā laʻana i loaʻa ka 0.4 wt.%, 0.6 wt.% a me 2 wt.% RuNi.CO adsorption ma ka Ru/Al2O3 hāpana hāʻawi i ka piko nui ma 2060 cm-1 a me kekahi peak ākea ma 1849 cm-1 i hoʻoili ʻia i ka linear CO adsorption ma Ru a me ka hoʻopaʻa ʻana ma luna o ʻelua mau ʻātoma Ru pili, kēlā me kēia CO39,40.No ka laʻana monometallic Ni, ʻike ʻia kahi kiʻekiʻe ikaika ma 2057 cm–1 wale nō, e pili ana i ka linear CO41,42 ma ka ʻāpana nickel.No ka laʻana RuNi, ma waho aʻe o ka piko nui ma 2056 cm-1, aia kahi poʻohiwi kūʻokoʻa i waena o ~2030 cm-1.Ua hoʻohana ʻia ke ʻano hoʻohālikelike kiʻekiʻe ʻo Gaussian no ka hoʻokaʻawale kūpono ʻana i ka hāʻawi ʻana i nā laʻana RuNi ma ka pae 2000-2100 cm-1 a me ka hoʻohele ʻana o CO ma ka ʻāina Ni (2056 cm-1) a me ka ʻāpana Ru (2031-2039 cm).ʻElua mau piko i hoʻopili ʻia i ka laina - 1) (Fig. 4b).ʻO ka mea hoihoi, mai ka Ru/Al2O3 laʻana (2060 cm–1) a i ka RuNi samples (2031–2039 cm–1), ka laina linearly pili CO peak ma ka ʻāina Ru e loaʻa ana i kahi ʻulaʻula nui a piʻi me ka hoʻonui ʻana i ka ʻike Ru.Hōʻike kēia i ka hoʻonui electronegativity o nā ʻāpana Ru i ka hāpana RuNi, ʻo ia ka hopena o ka hoʻoili electron mai Ni a i Ru, e hoʻonui ana i ka manaʻo electron d-π mai Ru a i ka antibonding CO 2π* orbital.Eia hou, no ka la'ana i loa'a ka 0.4 mass% RuNi, 'a'ohe bridging adsorption peak i 'ike 'ia, e hō'ike ana aia ka Ru particles ma ke 'ano he Ni atoms (SAA).I ka hihia o nā laʻana me 0.6 wt.% RuNi a me 2 wt.% RuNi, ʻo ka hiki ʻana mai o ka bridging CO e hōʻoia i ka noho ʻana o nā multimers Ru a i ʻole nā ​​pūʻulu, i ʻaelike maikaʻi me nā hopena AC-HAADF-STEM.
a In situ CO-DRIFTS spectra o Ni/Al2O3, Ru/Al2O3 a me 0.4 wt.%, 0.6 wt.%, 2 wt.% RuNi laana me ka helium kinoea kahe i loko o ka laulā 2100-1500 cm-1 no 20 min.b Scaled a me Gaussian-hoʻopili kikoʻī o ka RuNi/Al2O3 hāpana me nā kūlana kiʻekiʻe paʻa a me FWHM.c In situ Ru K-edge XANES spectra a me d EXAFS Fourier e hoololi i ke kikoo o na laana like ole.Hoʻololi ʻia ka nalu nalu K2 o nā hōʻailona XAFS K-edge Ru ma muli o ka nalu Morlet no nā laʻana e Ru mai e Ru foil, f 0.4 wt% RuNi a me g RuO2.“au” ʻo ia hoʻi nā ʻāpana kūʻokoʻa.
Hana ʻia ke ʻano o ka hoʻoheheʻe ʻana i ka X-ray ma ke ʻano maʻamau, ua hana ʻia ka spectra e aʻo i nā ʻano uila a me nā geometric o nā laʻana RuNi me nā mea hoʻohālike Ru foil a me RuO2.E like me ka hoike ana ma ka fig.4c, i ka emi ʻana o ka hoʻouka ʻana o ka Ru, e emi mālie ka ikaika o ka laina keʻokeʻo mai nā laʻana Ru/Al2O3 i nā laʻana RuNi.I kēia manawa, hōʻike ka ikaika o ka laina keʻokeʻo o ka spectrum XANES ma ka K-edge o Ni e hōʻike ana i kahi piʻi iki mai ke kumu Ni kumu i ka hāpana RuNi (Supplementary Fig. 22).Hōʻike kēia i ka hoʻololi ʻana i ka density electron a me ka hoʻonohonoho ʻana o nā pūhui Ru.E like me ka mea i hōʻike ʻia ma ka X-ray photoelectron spectroscopy (XPS) spectra (Supplementary Fig. 23), ua neʻe ka Ru0 peak o ka hāpana RuNi i kahi ikehu hoʻopaʻa haʻahaʻa a ua neʻe ka piko Ni0 i kahi ikehu hoʻopaʻa kiʻekiʻe e like me ka monometallic Ru a me Ni., e hōʻike pū ana i ka hoʻololi electron mai nā ʻātoma Ni a i nā ʻātoma Ru ma RuNi SAA.ʻO ka hōʻike manaʻo Bader uku o ka RuNi SAA (111) ili e hōʻike ana i ka lawe ʻana i nā kumu kūʻokoʻa ʻo Ru i nā koina maikaʻi ʻole (Ruδ-) i hoʻoili ʻia mai nā ʻātoma Ni subsurface (Supplementary Fig. 24), i kūlike me nā hopena DRIFTS a me XPS.No ke aʻo ʻana i ka ʻōnaehana hoʻonohonoho kikoʻī o Ru (Fig. 4d), ua hana mākou i ka hoʻonui X-ray absorption fine-grained spectroscopy (EXAFS) i ka hoʻololi Fourier.Laʻana i loaʻa iā RuNi 0.4 wt.Loaʻa i ka % kahi piko ʻoi loa ma ~2.1 Å, aia ma ka ʻāpana ma waena o nā pūpū Ru-O (1.5 Å) a me Ru-Ru (2.4 Å), hiki ke hoʻohui ʻia i ka hui Ru-Ni44, 45. Nā hualoaʻa kūpono EXAFS. (Nā Papa Hoʻohui 5 a me nā Kiʻi Hoʻohui 25-28) hōʻike i ke ala Ru-Ni he helu hoʻohui (CN) o 5.4, ʻoiai ʻaʻohe Ru-Ru a me Ru-O coordination ma 0.4 wt.% RuNi laʻana.Hōʻoia kēia e hoʻopuehu ʻia nā ʻātoma Ru nui a hoʻopuni ʻia e Ni, e hana ana i kahi huila monoatomic.Pono e hoʻomaopopo ʻia ʻo ka ikaika o ka piko (~ 2.4 Å) o ka hui ʻana o Ru-Ru e ʻike ʻia i kahi laʻana o 0.6 wt.% RuNi a hoʻonui ʻia i ka hāpana e 2 wt.% RuNi.Ma keʻano kūikawā, hōʻike ʻia ka hoʻopili ʻana o ka curve EXAFS ua hoʻonui nui ʻia nā helu hoʻohui Ru-Ru mai 0 (0.4 wt.% RuNi) a i 2.2 (0.6 wt.% RuNi) a piʻi hou aʻe i 6.7 (2 wt.% .% RuNi), kēlā me kēia. , e hōʻike ana i ka piʻi ʻana o ka ukana Ru, e hoʻohui mālie nā ʻātoma Ru.Ua hoʻohana hou ʻia ke K2-weighted wavelet transform (WT) o nā hōʻailona Ru K-edge XAFS e aʻo i ke kaiapuni hoʻonohonoho o nā ʻano Ru.E like me ka hoike ana ma ka fig.4e, Ru foil lobes ma 2.3 Å, 9.7 Å-1 e pili ana i ka haawi Ru-Ru.Ma kahi laʻana i loaʻa iā RuNi 0.4 wt.% (Fig. 4f) ʻaʻohe lobes ma k = 9.7 Å-1 a me 5.3 Å-1, koe wale no ka pilina waena o Ru me Ru atoms a me O atoms (Fig. 4g);ʻIke ʻia ʻo Ru-Ni ma 2.1 Å, 7.1 Å-1, e hōʻoia ana i ka hoʻokumu ʻana o SAA.Eia kekahi, ʻaʻole i hōʻike ʻia nā ʻokoʻa koʻikoʻi o ka EXAFS spectra ma ka K-edge o Ni no nā laʻana like ʻole (Supplementary Fig. 29), e hōʻike ana i ka liʻiliʻi o ka hoʻonohonoho hoʻonohonoho ʻana o Ni e ka ʻili Ru atoms.I ka pōkole, ua hōʻoia nā hopena o ka AC-HAADF-STEM, in situ CO-DRIFTS, a me nā hoʻokolohua XAFS ma kahi i ka hoʻomākaukau maikaʻi ʻana o nā catalysts RuNi SAA a me ka hoʻomohala ʻana o nā ʻāpana Ru ma Ni NPs mai nā atom hoʻokahi i Ru multimers ma ka hoʻonui ʻana i ka Ru haawe.Eia kekahi,ʻo nā kiʻi HAADF-STEM (Supplementary Fig. 30) a me EXAFS spectra (Supplementary Fig. 31) o ka RuNi SAA catalysts i hoʻohanaʻia i hōʻikeʻiaʻaʻole i loli nui ka moku'āina a me ka hoʻohuiʻana o nā Ru atoms ma hope o nā pōʻai 5, e hōʻoia ana. ʻo ia ka mea hoʻokūpaʻa RuNi SAA.
Hana ʻia nā ana H2-TPD no ke aʻo ʻana i ka adsorption dissociative o ka hydrogen ma nā catalysts like ʻole a ua hōʻike nā hopena i kēia mau catalysts he ikaika H2 dissociation mana me kahi kiʻekiʻe desorption ma ~ 100 °C (Supplementary Fig. 32).ʻAʻole i hōʻike ʻia nā hopena o ka loiloi quantitative (Supplementary Fig. 33) i ka hoʻopili pololei ʻana ma waena o ka reactivity a me ka nui o ka hydrogen desorption.Eia kekahi, ua hana mākou i nā hoʻokolohua me D2 isotopes a loaʻa i kahi kinetic isotope effect (KIE) waiwai o 1.31 (TOFH/TOFD) (Supplementary Fig. 34), e hōʻike ana he mea nui ka hoʻoulu ʻana a me ka dissociation o H2 akā ʻaʻole i ka palena palena.Ua hana ʻia nā helu DFT no ka noiʻi hou ʻana i ke ʻano adsorption a me ka dissociation o ka hydrogen ma RuNi SAA versus metallic Ni wale nō (Supplementary Fig. 35).No nā laʻana RuNi SAA, ʻoi aku ka maikaʻi o nā molekala H2 ma luna o nā mana Ru hoʻokahi me ka ikehu adsorption o -0.76 eV.A laila, hoʻokaʻawale ka hydrogen i ʻelua mau mana H hoʻoikaika ma nā kahua hollow o Ru-Ni RuNi SAA, e lanakila ana i ka pale ikehu o 0.02 eV.Ma waho aʻe o nā pae Ru, hiki ke hoʻopaʻa ʻia nā molekala H2 ma nā wahi o luna o nā ʻātoma Ni e pili ana iā Ru (ke ikehu adsorption: -0.38 eV) a laila hoʻokaʻawale ʻia i ʻelua Hs ma nā kahua hollow Ru-Ni a me Ni-Ni.ʻO ka pale atomika 0.06 eV.ʻO ka mea ʻē aʻe, ʻo nā pale ikehu no ka adsorption a me ka hoʻokaʻawale ʻana o nā molekala H2 ma ka ʻili Ni (111) he -0.40 eV a me 0.09 eV, kēlā me kēia.ʻO ka haʻahaʻa haʻahaʻa o ka ikehu a me nā ʻokoʻa liʻiliʻi e hōʻike ana e wehe maʻalahi ka H2 ma ka ʻili o Ni a me RuNi surfactants (Ni-site a i ʻole Ru-site), ʻaʻole ia he kumu nui e pili ana i kāna hana catalytic.
He mea koʻikoʻi ka adsorption o kekahi mau pūʻulu hana no ka hydrogenation koho o nā substrates.No laila, ua hana mākou i nā helu DFT no ka noiʻi ʻana i nā hoʻonohonoho kūpono o ka adsorption 4-NS a me nā pūnaewele ikaika ma ka ʻili RuNi SAA (111), a hōʻike ʻia nā hopena optimization ma ka Fig. 36e), kahi i loaʻa ai nā ʻātoma N ma nā kahua hollow Ru-Ni a ua hoʻopaʻa ʻia ʻelua mau ʻātoma O i ka interface Ru-Ni e hōʻike ana i ka pae haʻahaʻa haʻahaʻa adsorption ikehu (-3.14 eV).Hōʻike kēia i ka thermodynamically ʻoi aku ka maikaʻi o ka adsorption regime i hoʻohālikelike ʻia me ke kūpaʻa a me nā hoʻonohonoho like like ʻole (Supplementary Fig. 36a–d).Eia kekahi, ma hope o ka adsorption o 4-HC ma RuNi SAA (111), ua hoʻonui ka lōʻihi o ka N-O1 (L (N-O1)) i loko o ka hui nitro i 1.330 Å (Fig 5a), he nui loa. ʻoi aku ka lōʻihi ma mua o ka lōʻihi o ke kinoea 4- NS (1.244 Å) (Supplementary Fig. 37), ʻoi aku ma mua o L (N-O1) (1.315 Å) ma Ni (111).Hōʻike kēia i ka hoʻonui ʻia ʻana o ka adsorption o nā paʻa N-O1 ma ka ʻili o RuNi PAA i hoʻohālikelike ʻia me ka Ni (111) mua.
a Adsorption hoʻonohonoho o 4-HC ma Ni (111) a me RuNi SAA (111) (Eads) surfaces (ʻaoʻao a me luna nānā).Ru - violet, Ni - ʻōmaʻomaʻo, C - ʻalani, ʻO - ʻulaʻula, N - uliuli, H - keʻokeʻo.b In situ FT-IR spectra o kinoea a chemisorbed 4-HC ma monometallic surfactants Ni, Ru, RuNi (0.4 wt. %) a me 2 wt.% RuNi, pakahi.c Normalized in situ XANES a me d-phase-corrected Fourier EXAFS ma ka Ru K-edge o 0.4 wt % RuNi PAA i ka 4-NS adsorption (RuNi SAA–4NS) a me ka hydrogenation step (RuNi SAA–4NS–H2) .Transformation spectra ;…e Projection density of states (PDOS) of the first surface of RuNi SAA(111), N-O1 in gaseous 4-NS and adsorbed 4-NS on RuNi SAA(111).“au” ʻo ia hoʻi nā ʻāpana kūʻokoʻa.
No ka ho'āʻo houʻana i ka hana adsorption o 4-NS, ua hanaʻia nā ana FT-IR in situ ma Ni monometallic, Ru monometallic, 0.4 wt% RuNi (SAA), a me 2 wt% RuNi catalysts (Fig. 5b).Ua hōʻike ʻia ka spectrum FT-IR o ke kinoea 4-NS i ʻekolu mau piko hiʻona ma 1603, 1528, a me 1356 cm–1, i hāʻawi ʻia iā ν(C=C), νas(NO2), a me νs(NO2)46,47, 48.Ma ke alo o ka monometallic Ni, ʻike ʻia nā hoʻololi ʻulaʻula o nā kaha ʻekolu: v(C=C) (1595 cm–1), νas(NO2) (1520 cm–1), a me νs(NO2) (1351 cm–1) ., e hōʻike ana i ka chemisorption o nā hui C = C a me -NO2 ma ka ʻili Ni (ʻoi loa, i ka hoʻonohonoho ʻana o ka adsorption parallel).No kahi laʻana o ka monometallic Ru, ua loaʻa nā hoʻololi ʻulaʻula o kēia mau pūʻulu ʻekolu (1591, 1514, a me 1348 cm–1) pili i ka monometallic Ni, e hōʻike ana i kahi adsorption hoʻonui iki o nā pūʻulu nitro a me nā paʻa С=С ma Ru.I ka hihia o 0.4 wt.ʻO % RuNi (SAA), ka ν(C=C) ke kikowaena ma 1596 cm–1, kahi kokoke loa i ka monometallic Ni band (1595 cm–1), e hōʻike ana i nā hui vinyl e hoʻopili iā Ni ma ka RuNi Nā paena SAA.Eia kekahi, i ka hoʻokaʻawale ʻana i ka monometallic catalyst, ʻoi aku ka nāwaliwali o ka νs (NO2) band (1347 cm-1) ma mua o ka νas (NO2) band (1512 cm-1) ma 0.4 wt.% RuNi (SAA. ), ka mea i pili me ka cleavage o ka NO pili i -NO2 e hana i ka nitroso waena e like me mua study49,50.Uaʻike pūʻia kekahiʻano likeʻole i ka hāpana me kahi RuNi maʻiʻo o 2 wt.%.ʻO nā hopena i luna e hōʻoia i ka hopena synergistic o nā kikowaena bimetallic i PAA RuNi e hāpai i ka polarization a me ka dissociation o nā pūʻulu nitro, i ʻaelike maikaʻi me ka hoʻonohonoho adsorption maikaʻi loa i loaʻa i nā helu DFT.
Ua lawe ʻia ka spectroscopy XAFS ma kahi e aʻo ai i ka loli ikaika o ka ʻōnaehana uila a me ke kūlana hoʻonohonoho o RuNi SAA i ka wā 4-NS adsorption a me ka hopena catalytic.E like me ka mea i ʻike ʻia mai ka K-edge XANES spectrum o Ru (Fig. 5c), ma hope o ka adsorption o 4-HC, 0.4 wt.% RuNi PAA, ua hoʻololi nui ʻia ka ʻaoʻao absorption i nā ʻenehana kiʻekiʻe, i hui pū ʻia me ka piʻi ʻana o ka ikaika o ka laina keʻokeʻo, e hōʻike ana i ka ʻano Ru ʻO ka ʻoki ʻana i ka hapa ma muli o ka hoʻololi ʻana o ka electron mai Ru a i 4-NS.Eia kekahi, ke hoʻololi ʻia ʻo Fourier hoʻololi EXAFS spectrum o adsorbed 4-NS RuNi SAA (Fig. 5d) e hōʻike ana i ka hoʻonui maikaʻi ʻana o nā hōʻailona ma ~ 1.7 Å a me ~ 3.2 Å, i pili me ka hoʻokumu ʻana o ka hui Ru-O.Ua hoʻi ka XANES a me EXAFS spectra o 0.4 wt% RuNi SAA i ko lākou kūlana mua ma hope o ka hoʻokomo ʻana i ke kinoea hydrogen he 30 mau minuke.Hōʻike kēia mau ʻano ʻano i hoʻopili ʻia nā pūʻulu nitro ma nā pūnaewele Ru ma o nā paʻa Ru-O e pili ana i nā pilina uila.No ka XAFS spectra o ka Ni-K lihi in situ (Supplementary Fig. 38), ʻaʻole i ʻike ʻia nā loli i ʻike ʻia, ma muli paha o ka hopena o ka dilution o Ni atoms i ka māhele nui ma luna o nā ʻāpana Ni.ʻO ka mānoanoa wānana o nā mokuʻāina (PDOS) o RuNi SAA (Fig. 5e) e hōʻike ana i ke kūlana noho ʻole o ka hui nitro ma luna o ka pae Femi e hoʻonui a neʻe ma lalo o ka pae Femi i ke kūlana adsorbed, kahi e hōʻike ai i nā electrons mai ka d- moku'āina o RuNi SAA ho'ololi i ka moku'āina noho 'ole ma −NO2.ʻO kaʻokoʻa o ka uku hoʻopaʻa (Supplementary Fig. 39) a me ka Bader charge analysis (Supplementary Fig. 40) hōʻike i ka hoʻohui ʻana o ka electron density o 4-NS ma hope o kona adsorption ma ka ʻili o RuNi SAA (111).Eia kekahi, ua hoʻonui nui ʻia ka nui o ka uku -NO2 i hoʻohālikelike ʻia i ka hui vinyl ma 4-NS ma muli o ka hoʻoili electron ma ka interface Ru-Ni, e hōʻike ana i ka hoʻāla kikoʻī o ka paʻa NO i ka hui nitro.
Ma ka wahi FT-IR ua hana 'ia no ka nānā 'ana i ka catalytic kaʻina o ka 4-NS hydrogenation hopena ma ka catalyst samples (Fig. 6).No ka nickel catalyst mua (Fig. 6a), he emi iki wale no ka nui o ka nitro (1520 a me 1351 cm-1) a me C=C (1595 cm-1) i ike ia i ka hele ana i H2 no 12 min. hōʻike ʻia ʻo − ʻO ka hoʻoulu ʻana NO2 a me C=C ua nāwaliwali loa.Ma ke alo o ka monometallic Ru (Fig. 6b), ʻo ka ν(C=C) band (ma 1591 cm–1) e hōʻemi wikiwiki i loko o 0-12 min, aʻo nā νs (NO2) a me νas (NO2) e hoʻemi nui ʻia. .Slow Hōʻike kēia i ka hoʻoulu ʻana o ka hui vinyl no ka hydrogenation, e alakaʻi ana i ka hoʻokumu ʻana o 4-nitroethylbenzene (4-NE).I ka hihia o 0.4 wt.% RuNi (SAA) (Fig. 6c), nalo koke ka νs(NO2) (1347 cm–1) me ke komo ana o ka hydrogen, me ka popopo malie o ν(N=O);Ua ʻike pū ʻia kekahi pūʻulu hou i hoʻopaʻa ʻia ma 1629 cm-1, pili i nā haʻalulu o NH.Eia hou, hōʻike ka pūʻali no ν(C=C) (1596 cm–1) i kahi emi iki ma hope o 12 min.Hōʻoia kēia hoʻololi ikaika i ka polarization a me ka hydrogenation o -NO2 i -NH2 e 0.4 wt% RuNi (SAA) e pili ana i ka chemoselectivity kūʻokoʻa i ka 4-aminostyrene.No ka laana o 2 wt.% RuNi (Fig. 6d), ma waho aʻe o ka ʻike ʻia ʻana o kahi hui hou ma 1628 cm–1 i pili iā δ(NH), ʻo ka ν(C=C) pūʻulu e emi a nalowale me ka piʻi ʻana o ka pūʻulu nitro (1514). a me 1348 knm–1).Hōʻike kēia i ka C = C a me -NO2 i hoʻoikaika maikaʻi ʻia ma muli o ke kū ʻana o nā kikowaena interfacial Ru-Ru a me Ru-Ni, e pili ana i ka hoʻokumu ʻana o 4-NE a me 4-AE ma 2 wt.% RuNi catalyst.
In situ FT-IR spectra o 4-NS hydrogenation ma ke alo o monometallic Ni, b monometallic Ru, c 0.4 wt% RuNi SAA, a me d 2 wt% RuNi i H2 kahe ma 1700–1240 cm– Ua kakauia ka Range 1 e like me ka kinoea hopena ma hope o 0, 3, 6, 9 a me 12 minuke.“au” ʻo ia hoʻi nā ʻāpana kūʻokoʻa.ʻO ka hāʻawi ʻana i ka ikehu kūpono a me nā hoʻolālā kūpono kūpono no ka C=C hydrogenation a me NO scission i 4-NS ma e Ni(111) a me f RuNi SAA(111) surfaces.Ru - violet, Ni - ʻōmaʻomaʻo, C - ʻalani, ʻO - ʻulaʻula, N - uliuli, H - keʻokeʻo.ʻO nā "ads", "IS", "TS", a me "FS" e hōʻike ana i ke kūlana adsorption, ka mokuʻāina mua, ke kūlana hoʻololi, a me ka mokuʻāina hope.
Ua noiʻi ʻia nā ala kūpono no ka hoʻololi ʻana o 4-NS i Ni (111) a me RuNi SAA (111), me ka C = C hydrogenation a me ka NO bond cleavage, e nā helu DFT e wehewehe hou i ke kuleana koʻikoʻi o 4-NS.Nā ʻāpana o ka interface Ru-Ni no ka hana ʻana i nā pahuhopu 4-AS.No ka ili Ni(111) (Fig. 6e), nā pale ikehu no NO scission a me ka hydrogenation o nā hui vinyl i ka pae mua he 0.74 a me 0.72 eV, e hoike ana i ka hydrogenation chemoselective o na hui nitro ma 4-HC. maikaʻi ʻole.no nā ʻili nickel monometallic.ʻO ka mea ʻē aʻe, ʻo ka pale ikehu no NO dissociation he 0.46 eV wale nō ke kiʻekiʻe ma mua o ka RuNi SAA (111), ʻoi aku ka haʻahaʻa ma mua o ka C = C bond hydrogenation (0.76 eV) (Fig. 6f).Ua hōʻoia ʻole kēia i ka hoʻohaʻahaʻa pono ʻana o nā kikowaena interfacial Ru-Ni i ka pale ikehu no NO scission i nā pūʻulu nitro, e alakaʻi ana i kahi hōʻemi thermodynamically maikaʻi loa o nā pūʻulu nitro i hoʻohālikelike ʻia me nā pūʻulu C = C ma ka ʻili surfactant RuNi, e ʻae me nā hopena hoʻokolohua.
Ua noiʻi ʻia ke ʻano o ka hopena a me nā ʻāpana ikehu helu o 4-NS hydrogenation ma RuNi SAA ma muli o nā helu DFT (Fig 7), a ua hōʻike ʻia ka hoʻonohonoho adsorption kikoʻī o nā ʻanuʻu nui ma ka Fig 41. ʻAʻole i hoʻokaʻawale ʻia nā mea pale e hana i ka ikehu no nā molekele wai mai ka helu ʻana.nā hiʻohiʻona papa9,17.E like me ka hoike ana ma ka fig.7, ua hoʻopili mua ʻia nā molekala 4-NS e like me ka surfactant RuNi, a ua hoʻopaʻa ʻia ʻelua mau ʻātoma O i loko o ka hui nitro i nā kikowaena interfacial Ru-Ni (S0; step I).Ma hope iho, ua haki ka paʻa NO i hoʻopili ʻia i ka pūnaewele Ru, i hui pū ʻia me ka hoʻokumu ʻana o kahi nitroso intermediate (C8H7NO*) ma ke kahua kikowaena Ru-Ni a me O* ma kahi kahua Ni (S0 → S1 ma o TS1; ikehu. pale: 0.46 eV, kaʻanuʻu lua).Hoʻohana ʻia nā radical O* e nā ʻātoma H ikaika e hana i nā molekole H2O me kahi exotherm o 0.99 eV (S1 → S2).ʻO nā pale ikehu no ka hydrogenation o ka C8H7NO* waena (Nā Kii 42 a me 43) e hōʻike ana i ka hoʻouka ʻana o nā ʻātoma H reactive mai nā pūnaewele Ru-Ni hollow i nā ʻātoma O ma luna o nā N nā mana, e hopena i ka C8H7NOH * (S2 → S4; keakea ikehu TS2: 0.84 eV, ʻanuʻu III).A laila, ua hoʻohāhā ʻia nā ʻātoma N i C8H7NOH* e lilo i C8H7NHOH* ma hope o ka hele ʻana i ka pale 1.03 eV (S4→S6; step IV), ʻo ia ka pae wehewehe o ka hopena holoʻokoʻa.Ma hope aʻe, ua haki ka paʻa N–OH i C8H7NHOH* ma ke kikowaena Ru–Ni (S6 → S7; pale ikehu: 0.59 eV; pae V), a laila ua hoʻohāinu ʻia ʻo OH* i HO (S7 → S8; exotherm: 0.31 eV. ) Ma hope o kēlā, ua hoʻohuihui ʻia nā ʻātoma N o nā kahua hollow Ru-Ni i C8H7NH* e hana i ka C8H7NH2* (4-AS) me kahi pale ikehu o 0.69 eV (S8 → S10; step VI).ʻO ka hope, ua hoʻopau ʻia nā molekala 4-AS a me HO mai ka ʻili RuNi-PAA, a ua hoʻi ka catalyst i kona kūlana mua (step VII).ʻO kēia ʻano hana interfacial kū hoʻokahi ma waena o nā Ru atoms a me Ni substrates, i hui pū ʻia me ka hopena synergistic o ka doping host ma RuNi SAA, ka hopena i ka hana koʻikoʻi a me ka chemoselectivity o 4-NS hydrogenation.
Laiki.4. Hoʻolālā kiʻi o ka hana o ka hydrogenation reaction o NS i ka 4-AS ma ka ʻili RuNi PAA.Ru - violet, Ni - ʻōmaʻomaʻo, C - ʻalani, ʻO - ʻulaʻula, N - uliuli, H - keʻokeʻo.Hōʻike ka inset i ka hāʻawi ʻana i ka ikehu o 4-NS hydrogenation ma ka ʻili RuNi SAA(111), i helu ʻia ma ke kumu o DFT.Hōʻike ʻo “S0″ i ke kūlana mua, a ʻo “S1-S10″ e hōʻike ana i kahi ʻano o nā kūlana adsorption.ʻO "TS" kahi kūlana hoʻololi.ʻO nā helu i loko o nā bracket e hōʻike ana i nā pale ikehu o nā ʻanuʻu nui, a ʻo nā helu i koe e hōʻike ana i ka ikehu adsorption o nā mea waena.
No laila, ua loaʻa nā catalysts RuNi SAA me ka hoʻohana ʻana i nā hopena electrosubstitution ma waena o RuCl3 a me Ni NP i loaʻa mai nā LDH precursors.Hoʻohālikelike ʻia me ka monometallic Ru, Ni a me nā catalysts heterogeneous i hōʻike mua ʻia, ua hōʻike ʻo RuNi SAA i ka hopena catalytic maikaʻi no ka 4-NS chemoselective hydrogenation (4-AS hua: >99%; TOF waiwai: 4293 h-1).ʻO ka hōʻailona hui pū me AC-HAADF-STEM, in situ CO-DRIFTS, a me XAFS ua hōʻoia ʻo Ru atoms i immobilized ma Ni NPs ma ka pae hoʻokahi-atom ma o nā kaula Ru-Ni, i hui pū ʻia me ka hoʻoili electron mai Ni a Ru.Ma kahi XAFS, FT-IR nā hoʻokolohua, a me nā helu DFT i hōʻike ʻia e lawelawe ʻo Ru-Ni ma ke ʻano he kahua hana kūloko no ka hoʻāla ʻana o ka paʻa NO i ka hui nitro;ʻO ka synergism ma waena o Ru a me nā pūnaewele Ni e hoʻoikaika i ka hoʻoulu waena a me ka hydrogenation, a laila e hoʻomaikaʻi nui ai i ka catalytic pono.Hāʻawi kēia hana i ka ʻike i ka pilina ma waena o nā pūnaewele hoʻoikaika bifunctional a me ka ʻano catalytic o SAA ma ka pae atomic, e hoʻokaʻawale i ke ala no ka hoʻolālā kūpono o nā catalysts ʻelua ʻaoʻao me ka koho koho.
Ua kūʻai ʻia nā reagents analytical i hoʻohana ʻia i ka hoʻokolohua mai 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 a me ka nitrostyrene.Ua hoʻohana ʻia ka wai maʻemaʻe i nā hoʻokolohua āpau.
Ua hoʻohui ʻia ʻo Hierarchical NiAl LDHs ma ke ʻano he precursors e ka ulu in situ.ʻO ka mua, ua hoʻoheheʻeʻia ka urea (3.36 g), Al2 (SO4) 3 · 18H2O (9.33 g) a me ka sodium tartrate (0.32 g) i ka wai deionized (140 ml).Hoʻololi ʻia ka hopena hopena i kahi autoclave uhi ʻia ʻo Teflon a hoʻomehana ʻia i 170 ° C no 3 mau hola.Ua holoi ʻia ka wai i hoʻoheheʻe ʻia me ka wai a maloʻo loa, a ma hope o ka calcined ma 500 ° C (2 ° C min-1; 4 h) no ka loaʻa ʻana o Al2O3 amorphous.A laila ua hoʻopuehuʻiaʻo Al2O3 (0.2 g), Ni (NO3) 2 6H2O (5.8 g) a me NH4NO3 (9.6 g) i loko o ka wai maʻemaʻe (200 ml) a ua hoʻololiʻia ka pH i ~ 6.5 ma ka hoʻonuiʻana i ka wai amonia 1 mol l -1..Ua hoʻoili ʻia ka hoʻokuʻu ʻia i loko o kahi pahu a mālama ʻia ma 90 ° C no 48 mau hola e loaʻa ai ka NiAl-LDH.A laila ua ho'ēmiʻia ka pauka NiAl-LDH (0.3 g) i ke kahawai o H2 / N2 (10/90, v / v; 35 ml min-1) ma 500 ° C no 4 h (ka wela wela: 2 ° C min -1 ).Hoʻomākaukau i nā laʻana o ka nickel monometallic (Ni / Al2O3) i waiho ʻia ma Al2O3 amorphous.ʻO nā laʻana bimetallic i waiho ʻia o RuNi ua synthesized e ke ʻano electrodisplacement.ʻO ka mea maʻamau, ua hoʻopuehu ʻia kahi hāpana hou o Ni/Al2O3 (0.2 g) i loko o 30 ml o ka wai maʻemaʻe, a laila hoʻohui mālie ʻia kahi hopena o RuCl3 (0.07 mmol l-1) a hoʻoulu ʻia me ka ikaika no 60 mau minuke ma lalo o ka pale o ka lewa N2. .Ka hopena precipitate ua centrifuged, holoi me ka wai maʻemaʻe, a maloʻo i loko o ka vacuum umu ma 50 ° C no 24 h, loaʻa i ka hāpana i loaʻa 0.1% RuNi.Ma mua o ka loiloi catalytic, ua hoʻemi mua ʻia nā laʻana hou synthesized i kahi kahe H2 / N2 (10/90, v / v) ma 300 ° C (ka wela wela: 2 ° C min-1) no 1 h, a laila wela i loko. N2 Pualili i ka lumi wela.No ka ʻike: ʻo nā laʻana me ka Ru/Al2O3 maʻiʻo o 0.4% a me 2% ma ka nuipa, me ka Ru maoli maʻiʻo o 0.36% ma ka nuipa a me 2.3% ma ka nuipa, ua hoʻomākaukau ʻia e ka ua e ka ua a me ka wela ma 300 °C (ka hoʻohana ʻana o H2/ N2 : 10/90, v/v, ka wela wela: 2 °C min–1) no 3 mau hola.
Ua hana ʻia nā hoʻokolohua X-ray diffraction (XRD) ma kahi diffractometer Bruker DAVINCI D8 ADVANCE me kahi kumu hoʻoheheʻe Cu Kα (40 kV a me 40 mA).Ua hoʻohana ʻia kahi Shimadzu ICPS-7500 Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) no ka hoʻoholo ʻana i ka nui maoli o nā mea i loko o nā laʻana like ʻole.Ua kiʻi ʻia nā kiʻi scanning electron microscopy (SEM) me ka Zeiss Supra 55 electron microscope.Ua hana ʻia nā hoʻokolohua adsorption-desorption N2 ma kahi polokalamu Micromeritics ASAP 2020 a ua helu ʻia ka ʻāina kikoʻī me ka hoʻohana ʻana i ke ʻano multipoint Brunauer-Emmett-Teller (BET).Ua hana ʻia nā hiʻohiʻona o ka transmission electron microscopy (TEM) ma kahi JEOL JEM-2010 high-resolution transmission electron microscope.High Angle Aberration Corrected Scanning Transmission Electron Microscope Dark Field (AC-HAADF) - STEM me FEI Titan Cube Themis G2 300 me ka spherical aberration corrector a me Energy Dispersive X-ray Spectroscopy (EDS) pūnaewele a me JEOL JEM-ARM200F mea kani) a me nā ana palapala palapala EDS .Ua ana ʻia ke ʻano maikaʻi X-ray absorption spectroscopy (XAFS) ma kahi K-edge o Ru a me Ni K-edge ma nā kahawai 1W1B a me 1W2B o ka Beijing Synchrotron Radiation Facility (BSRF) o ka Institute of High Energy Physics (IHEP), Kina .Ke Kulanui o ʻEpekema (KAN).Pulsed CO chemisorption a me ka mahana-programmed hydrogen desorption (H2-TPD) hoʻokolohua i hana ma ka Micromeritics Autochem II 2920 mea kani me ka thermal conductivity detector (TCD).Ua hana ʻia nā hoʻokolohua DRIFTS in situ a me FT-IR ma kahi spectrometer infrared Bruker TENSOR II i hoʻolako ʻia me kahi cell reaction in situ i hoʻololi ʻia a me kahi mea ʻike MCT koʻikoʻi.Hōʻike ʻia nā ʻano kikoʻī kikoʻī ma ka ʻIke Hoʻohui.
ʻO ka mea mua, ua hoʻohui pono ʻia ka substrate (4-NS, 1 mmol), solvent (ethanol, 8 ml) a me ka catalyst (0.02 g) i kahi autoclave stainless steel 25 ml.Hoʻomaʻemaʻe ʻia ka reactor me 2.0 MPa (> 99.999%) hydrogen 5 mau manawa, a laila kaomi ʻia a hoʻopaʻa ʻia i 1.0 MPa me H2.Ua hoʻokō ʻia ka hopena ma 60 ° C me ka wikiwiki o ka hoʻoulu ʻana o 700 rpm.Ma hope o ka hopena, ua ʻike ʻia nā huahana i loaʻa e GC-MS a ua nānā ʻia me ka hoʻohana ʻana i kahi ʻōnaehana chromatography gas Shimadzu GC-2014C i hoʻolako ʻia me kahi kolamu capillary GSBP-INOWAX (30 m × 0.25 mm × 0.25 mm) a me kahi mea ʻike FID.Ua hoʻoholo ʻia ka hoʻololi ʻana o 4-nitrostyrene a me ka koho huahana penei:
Ua helu ʻia nā waiwai o ka huli ʻana (TOF) e like me ka mol 4-NS i hoʻololi ʻia i kēlā me kēia wahi metala mol i kēlā me kēia hola (mol4-NS mol-1 h-1) e pili ana i ka hoʻololi haʻahaʻa 4-NS (~ 15%).No ka heluna o nā pūnae Ru, nā pūnana pili Ru-Ni a me ka huina o nā ʻātoma metala ʻili.No ka ho'āʻo recyclability, ua hōʻiliʻili ʻia ka catalyst e ka centrifugation ma hope o ka hopena, holoi ʻia ʻekolu manawa me ka ethanol, a laila hoʻokomo hou ʻia i loko o ka autoclave no ka pōʻai catalytic aʻe.
Hoʻohana ʻia nā helu ʻana a pau o ka density functional theory (DFT).Hoʻohana ʻia ka hana PBE Generalized Gradient Approximation (GGA) e wehewehe i ka hoʻololi electron a me nā kūlana correlation.Hoʻohana ʻia ke ʻano Projector Augmented Wave (PAW) e wehewehe i ka pilina ma waena o nā nuclei atomic a me nā electrons.Hōʻike ke ʻano Grimm DFT-D3 i ka hopena o nā pilina van der Waals ma waena o ka substrate a me ka interface.Ka helu ʻana i nā pale ikehu ma o ka piʻi ʻana i nā pūnae elastic me ka hoʻonui kiʻi kiʻi (CI-NEB) a me nā ʻano Dimer.Ua hoʻokō ʻia kahi loiloi alapine o nā oscillations, e hōʻoia ana i ka hele ʻana o hoʻokahi alapine noʻonoʻo i kēlā me kēia mokuʻāina hoʻololi (Supplementary Figures 44-51).Hōʻike ʻia nā helu kikoʻī hou aku ma ka ʻike hou aku.
Hāʻawi ʻia ka ʻikepili nui e kākoʻo ana i nā ʻāpana ma kēia ʻatikala ma nā faila ʻikepili kumu.Loaʻa nā ʻikepili ʻē aʻe e pili ana i kēia noiʻi mai nā mea kākau ma muli o ke noi kūpono.Hāʻawi kēia ʻatikala i ka ʻikepili kumu.
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