Demand for motor fuels with a superlow sulfur content permanently increases. ..... sulfur atoms of the S-edge and hydride hydrogen forma- tion at the Co atoms.
3 3 2
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Mo d e rnco n c e p t so nc a t a l y s i so fh y d ro p r o c e s s in gan ds y n th e s i so fa l coho l s f roms y n g a sb yt r an s i t io nm e t a lsu l f i d e s* bV aE aA b D b V .M .K o gan ,a P .A .N iku l´ sh in , .S .D o r okh o v , .A .P e rm yak o v , .V .M o zha e v , .I .I shu t enk o , a a a O .L .E l i s e e v , N .N .R o zhd e s t v en ska ya , andA .L .La p idu s aN .D .Z e l in sk yIn s t i tu t eo fO r gan i cCh em i s t r y ,Ru s s ianA cad em yo fS c i en c e s ,
47L en in sk yp r o s p . ,119991 M o s c ow ,Ru s s ianF ed e ra t i on . Fa x :+7(499 )1355328 .Ema i l :vmk@ i o c .a c . ru b Sama raS ta t eT e chn i ca lUn i v e r s i t y , 244u l .M o l od o g va rd e i ska ya ,443100Sama ra ,Ru s s ianF ed e ra t i on . Fa x :+7(846 )2423580 .Ema i l :p .a .n iku l sh in@ gma i l . c om
Acon c ep tonth ed yn am i cn a tu r eo fa c t i v ec en t e r s(AC )o fth ec a t a l y s t sb a s edont r an s i t ion m e t a lsu l f id e si sd e s c r ib ed .Th econ c ep tfo rm edth eb a s i so fa"d yn am i c " mod e l ,a c co rd in gto wh i chACfo rm edandfun c t ion in gund e rth er e a c t ioncond i t ion sc ano s c i l l a t eb e tw e en l a y e r so f p romo t ed mo l ybd enumsu l f id e .Th e mod e la s sum e sth ee x i s t en c eo f" r ap id "and" s low "ACand th epo s s ib i l i t yo fth e i r in t e r t r an s fo rm a t iondu etoth er e v e r s ib l em i g r a t iono fsu l fu randp romo t e r b e tw e enth ec r y s t a l l i t el a y e r sinah yd ro g ena tmo sph e r e . Th ef r equ en c yo fth e s em i g r a t ion s (o s c i l l a t ion s )d e t e rm in e sth ec a t a l y s ta c t i v i t y .Ana s sump t ioni ssub s t an t i a t edth a tth eh yd ro r y s t a l l i t e sandd e su l fu r i z a t ion(h yd ro g en a t ions i t e sa r elo c a l i z eda tth er im so fCo (N i )MoS 2c d e su l fu r i z a t ion )s i t e sa r elo c a l i z edonth eed g e s . Th ep ropo s ed mod e lm ak e si tpo s s ib l eto d e v e lopc r i t e r i afo rth ee v a lu a t iono fth ee f f i c i en c yo fc a t a l y t i cp e r fo rm an c efo rh yd rod e su l fu r i z a t iono fh yd ro c a rbonr aw m a t e r i a l so fv a r iou st yp e sandfo rs yn th e s i so fh i gh e ra l coho l s f roms yn g a s . K e ywo r d s :h yd rop ro c e s s in g ,t r an s i t ion m e t a lsu l f id e s ,a c t i v eph a s e ,a c t i v ec en t e r ,th ioph en e , d i e s e lfu e l ,a l coho l s ,s yn g a s ,qu an tumch em i c a lc a l cu l a t ion s .
In t ro d u c t ion D em andfo r mo to rfu e l sw i thasup e r lowsu l fu rcon t en t p e rm an en t l yin c r e a s e s .1—3 H yd rop ro c e s s in gw i l lr em a in tob eth el a r g e s tvo lum ep ro c e s so fp e t ro l eump ro c e s s in g 4—6 a inth en e a r e s ty e a r s ndi t sro l ew i l lin c r e a s e ,s in c eth e m a x imuma c c ep t ab l esu l fu rcon t en tin mo to rfu e l sand o i l sb e com e in c r e a s in g l ys t r in g en t ,th ed ep tho fp e t ro l eum p ro c e s s in gin c r e a s e s ,and nont r ad i t ion a lh yd ro c a rbon sou r c e sa r eb e com in gin vo l v edinp e t ro l eump ro c e s s in g . Th er emo v a lo fsu l fu rcon t a in in go r g an i ccompound s f romo i lf r a c t ion si sac a t a l y t i cp ro c e s sth a tp ro c e ed sin h yd ro g enonth eN i (Co )Mo (W ) /A l2O3 c a t a l y s t s .Th ef i r s t c a t a l y s t sN i (Co )МоS / A l2O3 w e r eapp l i edin G e rm an y inth eB e r g iu sp ro c e s so fco a l l iqu e f a c t iona se a r l ya s inth e 1930 s . How e v e r ,s tud i e sa im eda tc l a r i f y in gth es t ru c tu r e o fth ea c t i v eph a s eandan a l y z in gth e wo rko fi t sa c t i v e c en t e r s(AC )a r ego in gon .P r e s en t l y ,th ed e v e lopm en to f n ewc a t a l y s t sandn ewt e chno lo g i e sfo rh yd rop ro c e s s in g a r er e l a t edtoth es tud yo fth ec a t a l y s t sa tth ea tom i cl e v e l . *Onth eo c c a s iono fth e80 thann i v e r s a r yo fth eN .D .Z e l in sk y In s t i tu t eo fO r g an i cCh em i s t r yo f th eRu s s i anA c ad em yo fS c i en c e s .
Th en ick e l—cob a l t—mo lybd enumsy s t em sexh ib i t c a ta ly t icsyn e r g i sm cau s ed byth efo rma t ion o fth e Co (N i )MoSph a s econ s i s t in go fn ano s i z edc r y s t a l l i t e s MoS2. Th i sph a s er ep r e s en t ss t a ck in go fl a y e r sl ink edb ysu l 7, 8 f id eb r id g e sw i thth eCo (N i )a tom sa c t in ga sp romo t e r s . Th e mod e rnth eo r e t i c a lcon c ep t sonc a t a l y s i so ft r an s i t ion m e t a lsu l f id e sa r eb a s edonth r e em a in mod e l s : mod e lo f 7, 8e 9—11 th eCo (N i )MoSph a s e , l e c t ronp romo t ion mod e l , 12 U and" r im— ed g e " mod e l . s in gth e s e mod e l si ti spo s s ib l etoe xp l a insom eco r r e l a t ion sb e tw e enth ec a t a l y t i c p rop e r t i e sandcompo s i t ionand /o rs t ru c tu r eo fth ea c t i v e compon en t . Th es tud yo fth eCoMoSc a t a l y s t so fd i f f e r en tcompo s i t ion sb yM ös sb au e rsp e c t ro s cop yshow edth a tth ec a t a l y s t scon t a inth eph a s eCoMoS inadd i t iontoth e ind i v idu 7, 8 a lcob a l tph a s e s CoA l nd Co d en t i f i ede a r l i e r . 2O4 a 9S 8i Th ec a t a l y t i ca c t i v i t yo fth eh yd rop ro c e s s in gc a t a l y s t si s r e l a t edtoth econ c en t r a t iono fth eCoMoSph a s e ,andi t s e x a c ts t ru c tu r ew a scon f i rm ed l a t e rb ye x t end edXr a yab so rp t ionf in es t ru c tu r e(EXAFS )sp e c t ro s cop y . Th eCo (N i )MoSph a s e so ftwot yp e sa r ed i s t in gu i sh ed : mono l a y e r ed( t yp eI )and mu l t i l a y e r ed( t yp eI I ) .Th ec a t a l y s t scon t a in in gth eCo (N i )MoSph a s eo ft yp eI Ia r e mo r e
Pub l i sh edinRu s s i aninI z v e s t i yaAkad em i iNauk .S e r i yaKh im i ch e ska ya ,No .2 ,pp .0332—0345 ,F eb ru a r y ,2014 . 10665285 /14 /63020332 ©2014Sp r in g e rS c i en c e+Bu s in e s sM ed i a ,In c .
T r an s i t ion m e t a lsu l f id ec a t a l y s i s
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a c t i v eth anth ec a t a l y s t scon t a in in gth eCo (N i )MoSph a s e o ft yp eIdu etoaw e ak e rin t e r a c t iono fsu l f id esu l fu rw i th th esuppo r tsu r f a c eandah i gh e rd e g r e eo fsu l fu r i z a t ion . E v id en c esu g g e s t in gach an g einth ea c t i v eph a s ecompo s i t ionandf i r s to fa l lp romo t e r(bo th N iandCo )und e rth e d e su l fu r i z a t ioncond i t ion si sg i v enins e v e r a l pub l i c a 13—19 T t ion s . h e mod e lo fth e Co (N i )MoSph a s edo e s no te xp l a inth i sph enom enon . Th ee l e c t ronp romo t e r mod e l9—11 a s sum e sth ee l e c t ront r an s f e rf romth ep ro mo t e ra tomto mo l ybd enumfo l low edb y Mo—Sbond w e ak en in g ,th er emo v a lo fsu l fu rinth efo rmo fh yd ro g en su l f id etoth eg a sph a s e ,andth efo rm a t iono fav a c an c yon th ec r y s t a l l i t e MoS nbo th mod e l s ,th en a tu r eo fc a t a l 2.I y t i ca c t ionw a sno te xp l a in ed . 12t I ti spo s tu l a t edinth e" r im— ed g e " mod e l h a tth e r e a r etwot yp e so fAC(h yd ro g en a t ion(HYD )andh yd rod e s u l fu r i z a t ion(HDS )s i t e s ) ,wh i cha r eid en t i c a lins t ru c tu r e bu ta r elo c a l i z edon" r im s "and" ed g e s "o f MoS2 c r y s t a l l i t e s ,r e sp e c t i v e l y . Ch an g in gth er a t ioo fth ed i am e t e rto h e i gh to fth ec r y s t a l l i t e ,i ti spo s s ib l etov a r yth er a t ioo f th e s es i t e sands e l e c t i v i t yo fth ec a t a l y s t in HYDand HDS r e a c t ion s . Th e mod e li gno r e sth ep romo t e rf a c to rand do e sno te xp l a inth es t ru c tu r eo fth e HYDand HDSs i t e s a tth ea tom i c l e v e landth er e a sonfo rwh i chth efo rm e ra r e lo c a l i z eda tth e" r im s "andth el a t t e ra r ea r r an g edonth e " ed g e s "o fth e MoS c r y s t a l l i t e s . 2 Thu s ,th ee x i s t in g mod e l so fth ea c t i v eph a s eo fth e c a t a l y s t sb a s edont r an s i t ion m e t a lsu l f id e sapp ro a chon l y p a r t i cu l a rp rob l em so fth ein f lu en c eo fth ep romo t e rand mo rpho lo g yo fth eunp romo t eda c t i v eph a s eonth ec a t a l y t i cp rop e r t i e s .Th efound a t ion so fth e"d yn am i c " mod e l d e v e lop edw i tha l low an c e fo rn ewcon c ep t sabou tth ewo rk 21 o fACa r ep r e s en t edinth i swo rk .20, 1 .Ex p e r im en t a lr e su l t sfo rm in gth eb a s i s o fth e" d yn am i c "mo d e l 1 .1 .R a d io i so to p i cs tu d i e so fth ed yn am i c so fa c t i v ec en t e r so fth ec a t a l y s t sb a s e dont r an s i t ionm e t a lsu l f i d e s .Th e u s eo fi so top e s35Sand3Hfo rs tud y in gth e HDS m e ch a n i smo fth ioph en em ad ei tpo s s ib l etoe s t ab l i shth a tinth e HDSp ro c e s sapo r t iono fsu l fu ro fth ec a t a l y s t( "mob i l e " 22—26 su l fu r ) i sd i sp l a c edb ysu l fu rcom in gf romth ioph en e . Th e"d i sp l a c em en t "m e ch an i smo fth ioph en econ v e r s ion onth esu l f id ec a t a l y s tsu r f a c ew a sp ropo s ed .27—29 A c co rd in g to th i sm e ch an i sm(S ch em e1 ) ,ad so rp t iono f th ioph en e
(o ro th e rsu l fu rcon t a in in go r g an i ccompound )a tth ean ion i cv a c an c yt r an s fo rm sth ec a t a l y s tin toa m e t a s t ab l e s t a t eb e c au s eth ev io l a t iono fth er a t ioo fsu r f a c eSHg roup s andan ion i cv a c an c i e s . Th eh yd ro g eno l y s i so fth e C—S bondandfo rm a t iono fah yd ro c a rbonf r a gm en to fth e su l fu rcon t a in in go r g an i ccompound in vo l v er e v e r s ib l yand d i s so c i a t i v e l yad so rb edh yd ro g en .Th i sp ro c e s si sa c com p an i edb yth efo rm a t iono fan ewSHg roupr e su l t in gin ach an g einth er a t iob e tw e enth enumb e ro fan ion i cv a c an c i e sandSHg roup s .Th i si sar e a sonfo rth et r an s i t ion o fth ec a t a l y s ttoa m e t a s t ab l es t a t e . Uponth ein t e r a c t ion w i thh yd ro g enth eSHg roupi sr emo v edtofo rm H2S ,and th ec a t a l y s t l e a v e sth em e t a s t ab l es t a t e .As i gn i f i c an tk in e t i c i so top ee f f e c t(K IE1H /3H=60 )ob s e r v edwh enth e HDS o fth ioph en e i scondu c t ed int r i t iuml ab e l edh yd ro g en in d i c a t e sth a tth e Н—Нbondc l e a v a g einan H2 mo l e cu l e i sar a t ed e t e rm in in gs t epo fth eo v e r a l lr e a c t ion .A m e ch a n i smw a sp ropo s edfo rth ein t e r a c t iono fth eSHg roupo f 30 A th ec a t a l y s tw i th H o f t h e g a s p h a s e . c c o r d i n g t o t h e 2 p ropo s ed m e ch an i sm , mo l e cu l a rh yd ro g eni scoo rd in a t ed b yon ea tomonth eSHg roupo fth ec a t a l y s t .A sar e su l t , ad e fo rm a t ioncompon en tapp e a r s inth ev ib r a t ion a lsp e c t rumo fth et r an s i t ioncomp l e x ,b e in gar e a sonfo rth e h i gh K IE .31 Th em e thod w a sd e v e lop edfo rth ee s t im a t iono fth e amoun tand mob i l i t yo fsu l f id esu l fu rin vo l v edinth efo r m a t iono f H2Sdu r in gth ioph en eh yd ro g eno l y s i sandth e 28, 32 I amoun tandr e a c t i v i t yo f ACinth er e a c t ion . th a s b e enshownth a tth e"mob i l e "su l fu ro fth eunp romo t ed MoS2 c a t a l y s tandth er e l a t eda c t i v es i t e sa r eun i fo rmin th e i rr e a c t i v i t y .Th ecob a l to rn i ck e lp romo t edc a t a l y s t con t a in stwot yp e so f"mob i l e "su l fu rw i thd i f f e r en tr e a c t i v i t yand ,h en c e ,twot yp e so fAC :" r ap id "and" s low . "Th e f r a c t iono fsu l f id esu l fu ra c coun t sfo r~50%o fth ea c t i v e su r f a c ea tom so fth eunp romo t edc a t a l y s t s MoS l 2/A 2O3 32 H andth a tinth ep romo t edc a t a l y s t si s75% .28, ow e v e r , th es t ru c tu r eo fth e s es i t e sr em a in edun c l e a r . Th er e a c t iono fah yd ro g enmo l e cu l ew i thth eSHg roup onth e Mo andSed g e so f mo l ybd enumd i su l f id ew a s 3 3s r e c en t l y tud i edu s in g th eDFTm e thod .Th er ibbonmod e l o f th ec r y s t a l l i t eed g ew a su s ed in th ec a l cu l a t ion s .Th een e r g yp ro f i l eo fth er e a c t iono f mo l e cu l a rh yd ro g enandSH g rouponth esu l f id i z ed(50% ) Moed g ew i thth efo rm a t ion o fb r id g in gh yd r id eandh yd ro g ensu l f id emo l e cu l ew a scon s t ru c t ed(F i g .1 ) .Th ea c t i v a t ionen e r g yo fth ep ro c e s si s 1 .35eV ,andth eendo th e rm i ce f f e c ti s0 .96eV .Inth i s
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