SYNTHESIS OF DME BY CO2 HYDROGEN- ATION OVER La2O3-MODIFIED CuO ZnO ZrO2/HZSM-5 CATALYSTS

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1 Aville on line t Assoition of the Chemil Engineers of Seri AChE Chemil Inustry & Chemil Engineering Qurterly Chem. In. Chem. Eng. Q. 23 (1) 4956 (2017) CI&CEQ YAJING ZHANG 1,3 YU ZHANG 1 FU DING 1,3 KANGJUN WANG 1,3 XIAOLEI WANG 2 BAOJIN REN 1 JING WU 1 1 College of Chemil Engineering, Shenyng University of Chemil Tehnology, Shenyng, Chin 2 Shool of Siene, Shenyng University of Tehnology, Shenyng, Chin 3 Lioning Co-innovtion Center of Fine Chemil Inustry, Shenyng, Chin SCIENTIFIC PAPER UDC : : SYNTHESIS OF DME BY CO2 HYDROGEN- ATION OVER L2O3-MODIFIED CuO ZnO ZrO2/HZSM-5 CATALYSTS Artile Highlights L-moifie CuO-ZnO-ZrO2/HZSM-5 tlysts were prepre y n oxlte o-preipittion metho L-moifie CuO-ZnO-ZrO2/HZSM-5 tlysts show higher tlyti performnes The tlyti performnes of the tlysts re strongly epenent on the L ontent Astrt A series of L2O3-moifie CuO-ZnO-ZrO2/HZSM-5 tlysts were prepre y n oxlte o-preipittion metho. The tlysts were fully hrterize y X-ry iffrtion (XRD), N2 sorption-esorption, hyrogen temperture progrmme reution (H2-TPR), mmoni temperture progrmme esorption (NH3-TPD), n X-ry photoeletron spetrosopy (XPS) tehniques. The effet of the L2O3 ontent on the struture n performne of the tlysts ws thoroughly investigte. The tlysts were evlute for the iret synthesis of imethyl ether (DME) from CO2 hyrogention. The results isplye tht L2O3 ition enhne tlyti performne, n the mximl CO2 onversion (34.3%) n DME seletivity (57.3%) were otine over the tlyst with 1% L2O3, whih ue to the smller size of Cu speies n lrger rtio of Cu + /Cu. Keywors: CO2 hyrogention; imethyl ether; L2O3 promoter. Cron ioxie emission hs use irreversile limte hnges ue to its greenhouse effet [1]. CO2 pture n storge is one of effiient metho for reuing the CO2 emissions. However, this tehnology requires high ost [2]. Chemil reyling of CO2 is nother min option, whih is presente s n eonomilly ttrtive n sustinle metho. CO2 n e onverte into methnol, imethyl ether (DME), methne n syngs (CO+H2) [3], roxyli is, et. Among them, synthesis of DME hs een pi speil ttention sine DME n e pplie s len fuel, oolnt, propellnt, n is n importnt hemil intermeite [4]. The hemil retions ourring in iret onversion of CO2 to DME n e esrie y the following equtions [5]: Corresponene: F Ding, K. Wng, College of Chemil Engineering, Shenyng University of Chemil Tehnology, Shenyng , PR Chin. E-mil: F. Ding, ingfu@syut.eu.n; K. Wng, ngle_79@163.om Pper reeive: 11 July, 2015 Pper revise: 8 Jnury, 2016 Pper epte: 19 Ferury, 2016 CO2 3H2 CH3OH H2O, H 49.4kJ/ mol (1) 2CH3 OH CH3OCH 3 H2O, H 23.4 kj/ mol (2) CO2 H2 CO H2O, H 41.2 kj/ mol (3) For the methnol synthesis (retion (1)), CuO ZnO ZrO2 tlyti system is onsiere s more fvorle thn the tritionl CuO ZnO Al2O3, euse the intertion of Cu metl prtiles with ZnO n ZrO2 le to the stiliztion of mix of Cu n Cu δ+ (not Cu 2+, Cu 1+ n Cu) [6]. For the methnol ehyrtion proess (retion (3)), soli-i tlysts (HZSM-5, γ-al2o3 n sulfte zironi) re employe [7]. HZSM-5 is wiely pplie for methnol ehyrtion euse: 1) it hs very high tlyti tivity t the optimum retion temperture; 2) it is more resistnt towr poisoning of i sites y the wter ue to more hyrophoi hrter; 3) preominne of Brønste-type iity, whih n promote the DME yiel [8]. However, H-ZSM-5 presents the isvntges of nrrow pore size n strong i sites, whih 49

2 Y. ZHANG et l.: SYNTHESIS OF DME BY CO2 HYDROGENATION Chem. In. Chem. Eng. Q. 23 (1) 4956 (2017) will limit retnt moleules iffusion n le to formtion of seonry prouts, respetively. Witoon et l. evelope sulfte zironi tlyst with 20% sulfur-loe on ZrO2 s methnol ehyrtion tlyst, the yiel of methnol n DME over CuO ZnO ZrO2/20S-ZrO2 oth higher thn those over CuO -ZnO ZrO2/H-ZSM-5, ut the stility of the former tlyst is little poor [9]. Up to now, the onversion of CO2 n the seletivity of DME re still not high. To enhne the tlyti tivity, efforts hve een resse y ing promoters for methnol synthesis tlyst, esies eveloping new preprtion methos [10-14]. Our previous results showe tht V n Mn oxies moifie CuO ZnO ZrO2/HZSM-5 exhiite higher tlyti performne [15-16]. L2O3, s rre erth metl oxie, is onsiere s owing some si hrter [17], n it n promote mny metl oxie tlyti retions. Guo et l. [18] investigte tlysis performne of L oping Cu/ZrO2 for CO2 hyrogention to methnol, n they foun the mount of si site inreses with L loing n the presene of L enhne the seletivity of methnol. Go et l. reporte pproprite mount of L n erese the rystllite size of CuO n enhne the ispersion of Cu [19]. Sun s group hs investigte the effet of L on the performne of Cu/Zn/Al tlysts vi hyrotlite-like preursors for CO2 hyrogention to methnol, n the results showe L ition not only le to higher BET speifi surfe re n Cu ispersion, ut lso inrese the totl numer of si sites n proportion of strongly si sites [20]. Furthermore, Sun s group lso reporte tht ition of Zr to L-Cu-Zn-O with perovskite struture tlyst, for synthesis of methnol from CO2 hyrogention, will le to smller prtiles, lower reution temperture, higher Cu ispersion, lrger mount of hyrogen esorption t low temperture s well s higher onentrtion of si sites re otine [21]. However, the introution of L2O3 into the CuO ZnO -ZrO2/HZSM-5 tlyst for CO2 to DME hs not een reporte. Herein, L2O3-moifie CuO-ZnO-ZrO2/HZSM-5 tlysts with ifferent L2O3 ontent were prepre, iming t investigting the effet of L2O3 moifition on the struture n performne the tlysts. EXPERIMENTAL Ctlyst preprtion The L2O3 moifie CuO-ZnO-ZrO2/HZSM-5 (CuO:ZnO:ZrO2 mss rtio: 5:4:0.2) tlysts, revite s CZZLxH where x stns for theoretil L2O3/CZZ wt.%, were prepre y n oxlte o-preipittion metho (CZZLx/HZSM-5 mss rtio: 2:1), HZSM-5 (SiO2/Al2O3 mole rtio: 50) ws purhse from Ctlyst Plnt of Nnki University (Chin). The preprtion metho is sme s esrie in other work [15]. In rief, first, metl nitrtes were issolve into ertin mount of ethnol (enote s solution A); H2C2O42H2O (200 mol.% of metl nitrte) ws lso issolve into ethnol (solution B). Then, solutions A n B were slowly roppe into eker ontining HZSM-5 suspension in ethnol suspension kept uner stirring t 333 K. The suspension ws sele n ge for 2 h n then the ethnol ws evporte t 353 K to get preipitte. Finlly, the preipitte ws rie t 393 K for 12 h n line in ir t 673 K for 4 h. Ctlyst testing Ctlyti performne ws evlute in ontinuous-flow fixe-e retor me of stinless steel with insie imeter of 0.01 m. First, the tlyst ws reue with 10% H2/N2 t 573 K for 3 h uner tmospheri pressure. Then it ws oole to 653 K n retnt gs flow ws introue, rising the pressure to 3.0 MP, the retion temperture ws 543 K. The exit line ws hete to prevent onenstion. The prouts were nlyze on line with gs hromtogrph (SP2100A) equippe with oth TCD (for CO n CO2, GDX-101 onnete with Porpk T olumn) n FID (for CH4, CH3OH n CH3OCH3, Porpk Q olumn). Conversion n seletivity vlues were lulte y internl stnr metho [22]. XCO2, Spi n YDME represent the onversion of CO2, the seletivity of the prout (DME, MeOH n CO) n the yiel of DME, respetively. Eh experimentl t ws orrespons to n verge of three inepenent mesurements, with error of ±2%. CO2,in CO2,out N2,in N2,out X CO (4) 2 CO2,in N 2,in Pi S Pi (5) 1 CO 2,out where Pi stns for the onentrtion of speifi i prout (DME, MeOH orco): YDME SDMEX CO 2 (6) Ctlyst hrteriztion XRD mesurements were performe on Rigku D/mx 2500p X-ry iffrtometer with Cu-Kα 50

3 Y. ZHANG et l.: SYNTHESIS OF DME BY CO2 HYDROGENATION Chem. In. Chem. Eng. Q. 23 (1) 4956 (2017) rition ( = Å) t sn rte of 4 min -1 t 50 kv n 250 ma. For the reue tlysts were first reue with 10% H2/N2 t 573 K for 3 h, n oole to room temperture uner the N2 flow, n then keep it into ottle full of N2 n sen it to XRD hmer immeitely. The rystllite size ws lulte using the Sherrer eqution. BET surfe res were mesure y N2 sorption t 77 K using Qunthrome Autosor 1-C. Before mesurements, smples were egsse uner vuum t 573 K for 4 h. H2-TPR ws rrie out in 10% H2/Ar flowing t 50 ml min -1, using rmp rte of 10 K min -1 to 773 K. NH3-TPD ws onute on Chemisor from 373 to 873 K. XPS mesurements were performe on n ESCALAB-250. The tlysts were first reue with 10% H2/N2 t 573 K for 3 h, n oole to room temperture uner the N2 flow, then put into the hmer of X-ry photoeletron spetrometer immeitely for mesurement. The ext omposition of the surfe of the tlyst ws etermine y XPS. Aiity on the tlyst ws mesure on NICOLET 500 FT-IR through pyriine sorption. The smple ws prepre to the lo slie, whih ws sujet to purifition uner vuum pressure P t 673 K, fter ooling own to the room temperture, pyriine ws sore for 0.5 h. Desorption ws rrie out y progrmming temperture to 423 K. The infrre spetrum ws generte within the sope of m 1 t room temperture. RESULTS AND DISCUSSION Ctlyti performne of tlysts The tlyti performnes of CZZLxH tlysts with vrying L2O3 ontent re summrize in Tle 1. The mjor prout ws DME, n the sie prouts were methnol, CO n tre hyrorons. The mount of hyrorons ws less thn 1% n therefore they were neglete. The CO2 onversions n DME seletivities over the L2O3-moifie tlysts re higher thn those over unmoifie one (CZZL0H), initing tht L2O3-moifition n effiiently enhne the tlyti performnes. The CZZL1H exhiite the mximum CO2 onversion n DME seletivity of 34.3 n 57.3%, respetively. CO2 onversion over CZZL1H inreses 18.6%, ompre with CZZL0H. The influene of the tlyst omposition on the performne oes not seem istint, whih is ue to the thermoynmi regime of retion test euse of omintion of high temperture n long ontt time. If the temperture is erese to 533 K, the ifferenes of onversion n DME seletivity etween CZZL1H n CZZL0H eome muh lrger (Tle 2). It is lso note tht the seletivity of CO is high (out 30%), whih my ue to the higher retion temperture of 543 K. CO ws proue y reverse wtergs retion, the retion hs enothermi hrter, s shown in retion (2). Menwhile, ompre to methnol synthesis, the RWGS retion hs higher pprent tivtion energy [23], initing tht the inrese in CO proution is fster thn tht of methnol with higher retion temperture. The seletivity of CO over CZZL1H exhiite the miniml vlue, initing tht ertin mount of L2O3 n inhiit the RWGS retion. However, s Go et l. pointe out, further work nees to e rrie out to investigte how L2O3 hnges the RWGS retion [19]. In orer to further inrese the DME yiel, the tlyti performne of the CZZL1H tlyst ws lso investigte t lower gs hourly spe veloity. As shown in Tle 2, when the GHSV ws s low s 1800 h -1, the CO2 onversion n DME seletivity inrese to 36.4 n 58.2%, respetively. The inrese of the onversion n e ttriute to the longer ontt time of CO2 n H2 over the tlyst t lower GHSV. Similrly, methnol ehyrtion n proee to higher egree with inresing ontt time, leing to higher DME seletivity. In ition, ontrst experiment ws rrie out t retion pressure of 5 MP while keeping other onitions onstnt. DME seletivity inrese y pproximtely 7.3% n CO seletivity erese y 24.6% ompre with those otine t 3 MP. This result suggests tht n inrese of retion pressure n improve the tlyti performne. The struture of tlyst Figure 1A shows the XRD ptterns of CZZLxH tlysts. The peks ppering t 35.5, 38.7, 48.7, Tle 1. Ctlyti performnes of the tlysts; retion onitions: T = 543 K; p = 3.0 MP; CO2:H2 = 1:3; GHSV = 4200 h -1 Ctlyst Conversion of CO2, % Seletivity, % DME CH3OH CO DME Yiel, % DME Proutivity, g g t -1 h -1 CZZL0H CZZL0.5H CZZL1H CZZL2H

4 Intensities (. u.) Intensities (. u.) Y. ZHANG et l.: SYNTHESIS OF DME BY CO2 HYDROGENATION Chem. In. Chem. Eng. Q. 23 (1) 4956 (2017) Tle 2. Ctlyti performnes of the tlysts t ifferent retion onitions; retion onitions: CO2:H2 = 1:3 Ctlyst T K Conversion of CO2 % p MP GHSV h -1 Seletivity, % DME CH3OH CO DME Yiel % DME Proutivity g g t -1 h -1 CZZL1H CZZL1H CZZL1H CZZL0H CZZL1H CuO ZnO HZSM-5 A HZSM-5 ZnO Cu * * * * B Thet (eg) Thet (eg) Figure 1. A) XRD ptterns of L2O3-moifie CuO ZnO ZrO2/HZSM-5 n B) reue tlysts: ) CZZL0H; ) CZZL0.5H; ) CZZL1H; ) CZZL2H. n 66.2 n e srie to CuO phse (tenorite, JCPDS ), the peks t 31.7, 34.3, 36.6, 56.5, 62.8 n 67.8 n e inexe to ZnO phse (JCPDS ), n the peks ppering in the 2 rnge of elong to HZSM-5 (JCPDS ). No peks elonging to ZrO2 or L2O3 re oserve, initing tht ZrO2 n L2O3 re morphous or well isperse in tlyst oy. The intensities of the peks ssigne to CuO n ZnO wekene n the withs of the peks roene grully with inresing L2O3 ontent from 0 to 1%, then they eme shrper n nrrower gin when L2O3 ontent ws 2%. This result inites tht the ition of proper mount of L2O3 n enhne the ispersion of CuO n ZnO [24]. This hnging tren n e well reflete in the hnging trens of Cu n CuO grin size, s shown in Tle 3. Tle 3. Physiohemil properties of the tlysts; iffrtion pek t 2θ 38.7 for CuO n 43.3 for Cu Ctlyst SBET / m 2 g 1 CuO DXRD / nm CZZL0H CZZL0.5H CZZL1H CZZL2H Cu The XRD ptterns of the reue tlysts re shown in Figure 1B. The iffrtion peks t 2θ vlues of 43.3, 50.4 n 74.1 n e inexe to the rystl plnes of (111), (200) n (220) of metlli opper phse, respetively (JCPDS ). No iffrtion peks elonging to the CuO phse oul e etete, suggesting ll CuO speies h een reue to opper. The intensities of the peks ssigne to Cu n ZnO hnge in similr tren s those of CuO n ZnO (Figure 1A). The speifi surfe res n the lulte rystllite sizes of the tlysts using Sherrer s eqution re liste in Tle 3. The SBET inrese from of CZZL0H to m 2 g -1 of CZZL1H, n then erese to m 2 g -1 for CZZL2H. The hnging tren of the DCu is opposite to the tren of the SBET, minimum of 10.5 nm is otine over CZZL1H. Although the SBET hnge is not s signifint s DCu, the tren is in orne with XRD results. Comining the results in oth Tles 1 n 3, it n e oserve tht CZZL1H shows the smllest Cu rystllite size n the est tlyti performne, whih inites the tivity is losely relte to the rystllite size of Cu. Guo et l. lso reporte the tlyti performne of Cu-TiO2-ZrO2 relte to the rystllite size of CuO [25]. 52

5 Consumption of H 2 (.u.) Ammoni esorption/.u Y. ZHANG et l.: SYNTHESIS OF DME BY CO2 HYDROGENATION Chem. In. Chem. Eng. Q. 23 (1) 4956 (2017) The reuiility of tlyst H2-TPR results re epite in Figure 2. It is ovious tht L2O3 moifition isplys signifint effet on the intertion etween the metl n the rriers. Eh tlyst exhiits ro pek with pek mximum in K, orresponing to the reution of CuO to Cu [26]. For the tlysts with inresing L2O3 ontent from 0 to 0.5 or 1%, the peks mxim shift to higher temperture from 529 to 554 or 556 K while no shpe hnges re oserve, whih inites the intertion etween ZnO n CuO or L2O3 n CuO eomes stronger [19,23,27]. This result seems onfliting with XRD result. Aoring to XRD result, the ispersion of CuO eomes etter n the rystlline size eomes grully smller with L2O3 ition mount from 0 to 1%, suggesting tht the reuiility of CuO shoul eome esier. This ft implies L2O3 moifition still plys nother role. For CZZL2H tlyst, it is evient tht the H2- -TPR hnge teneny eomes more ifferent n the pek mximum shifts towrs the lower temperture, initing the reuiility of CuO eomes esier [28,29]. It is onlue tht L2O3 moifition hs t lest two roles. On one hn, L moifition promotes the ispersion of CuO, leing to esier reution of CuO; on the other hn, L2O3 moifition enhnes the intertion etween CuO n other metl oxies resulting in more iffiult reution proess. The two effets ompete with eh other n the reution temperture is epenent on whih effet is preominnt. Xiong et l. lso foun tht the L2O3 n inrese the ispersion of Co/AC tlysts, wheres the reution temperture shifte to higher position ue to stronger intertion [30]. Surfe iity of tlyst Figure 3 shows the NH3-TPD results otine for pure HZSM-5 n CZZLxH tlysts. The totl ii mount, the strength n the frtion of vrious i sites re summrize (supporting info, ville from the uthors upon request). On pure HZSM-5 profile, two NH3 esorption peks re oserve, initing the existene of t lest two ifferent i strengths. In generl, the pek lote in K n K n e ttriute to wek n strong i strengths, respetively [31]. But for ll tlysts, three NH3 esorption peks, in the temperture regions of K, K n K re oserve, enote s α, β n γ pek, whih n e ssigne to wek, meium n strong i strengths of HZSM-5, respetively [32]. This result is similr with tht of the reporte V-moifie tlyst [15]. Aoring to the stuy, the reson why the tlysts showe nother more NH3 esorption pek thn pure HZSM-5 is minly srie to the ft tht strong i strength on pure HZSM-5 re loke n moifie y metl oxies n oxli i, respetively. Compre with L2O3-free tlyst, peks α n β on the other urves shift little to higher temperture with the inresing L2O3 ontent, implying tht the wek n meium i strengths eome stronger; on the ontrry, the pek γ shifts little towrs lower temperture, initing strong i strength eomes weker. It is lso worth noting tht the totl i mount ereses with the inresing mount of L2O3 from 0.5 to 1%, whih n e expline y the si hrter of L2O3. Sugi et l. lso oserve this effet n suggeste tht L2O3-moifition resulte in reuing the support iity [33]. However, ontinuous ition of L2O3 to 2% inreses the totl 461 K 421K 427K 499 K 500 K 599K 597K 656K Temperture (K) Figure 2. H2-TPR profiles of tlysts: ) CZZL0H; ) CZZL0.5H; ) CZZL1H; ) CZZL2H Temperture, Tempertue K (K) Figure 3. NH3-TPD profiles of pure HZSM-5 n the tlysts: ) HZSM-5; ) CZZL0H; ) CZZL0.5H; ) CZZL1H; e) CZZL2H. e 53

6 Intensities (. u.) Y. ZHANG et l.: SYNTHESIS OF DME BY CO2 HYDROGENATION Chem. In. Chem. Eng. Q. 23 (1) 4956 (2017) i mount gin. Previously pulishe stuies propose tht there re two resons for the iity mount inrese [34]. One is tht the L 3+ hs some Lewis ii property originte from n empty f oritl; the other reson is tht Si-OH n Al-OH in the zeolite frmework re polrize y L 3+, whih result in stronger iity. Therefore, the iity of the CZZLxH tlysts is epenent on the L2O3 ontent. Moreover, L2O3 moifition n lso ffet the onentrtion n istriution of the three i strengths of HZSM-5 in the tlysts. With the inresing mount of L2O3, the onentrtion n frtion of meium i strength inrese n those of strong i strength eome smller s ompre to those on CZZL0H, ut the ifferene is too smll (supporting info). It is generlly onsiere tht the strong ii strength on HZSM-5 zeolite promotes the genertion of seonry prouts like hyrorons, resulting in low seletivity to DME [6]. However, here the hnge of the iity oul not e ftor ounting for the higher DME seletivity euse the methnol seletivity of the vrious tlysts ws lmost the sme, s shown in Tle 1. This result suggests tht the iity of the tlysts is strong enough to effiiently onvert the proue methnol to DME. In ition, the iity of Brønste i sites n Lewis i sites for CZZL0H n CZZL1H tlysts were etermine (supporting info, ville from the uthors upon request). The results show the iity of oth type i sites of CZZL1H erese ompre CZZL0H, thus it n e inferre tht there is no iret reltionship etween the seletivity of DME n the hnge of i type of the two tlysts. So, the improvement of DME seletivity is ue to the erese in CO seletivity resulte from the Cu-se tlyst ut not from the i omponent of the ifuntionl tlysts. In ition, oring to the literture, it oul e speulte tht the introution of L2O3 into tlyst will inrese the surfe siity of tlyst, whih in turn promotes the sorption of CO2 n sequene enhnes the yiel for methnol, finlly DME seletivity is inrese fter methnol ehyrtion [18]. Results of XPS investigtions The reue CZZLxH tlysts hrterize y XPS, the ining energy of Cu2p3/2, Zn2p3/2, s well s the surfe ompositions of the tlysts re summrize (supporting info, ville from the uthor upon request). For ll the reue tlysts, ining energies (BE) of Cu2p3/2 re lote t out ev, whih re the hrteristi peks of reue Cu + /Cu speies [35]. The ining energy shifte to higher positions with inresing mounts of L2O3, whih inite stronger intertion etween CuO n other metl oxies rriers [36]. For the purpose of istinguishing Cu + from Cu speies, their kineti energies in the XAES Cu LMM line positions were mesure (Figure 4). The Cu LMM spetr show ro n symmetril pek, implying the oexistene of Cu + n Cu in the surfe of the tlysts. Two symmetril peks entere t ner n ev n e otine y eonvolution, whih re orresponing to Cu + n Cu speies, respetively [37]. Aitionlly, Cu + /Cu n e lulte se on the results. Volni shpe hnge trens of the Cu + /Cu versus L ition ontent re oserve, the CZZL1H exhiite the mximum of 0.144, whih my onsequently le to higher tivity ue to the stiliztion of Cu + fvoring the hyrogention of CO2 [38]. The ining energies (BE) of Zn2p3/2 for ll tlysts re lote t out ev, whih re lose to the hrteristi peks of ZnO speies [39]. Compre to the nominl surfe ompositions of the tlysts, it n e seen tht the tul surfe omposition Cu/Zn erese signifintly, implying enrihment of Zn. Similrly, L2O3 ontent is muh higher on the surfe. It is worth noting tht is L2O3 is not etetle in CZZL0.5H, possily euse the ontent is too smll to give enough signl Kineti Energy (ev) Figure 4. Cu LMM XAES spetr of the reue tlysts: ) CZZL0H; ) CZZL0.5H; ) CZZL1H; ) CZZL2H. CONCLUSIONS L2O3 moifition hs gret impt on the tlyti performne of CuO-ZnO-ZrO2/HZSM-5 tlysts for promoting iret CO2-to-DME. L2O3-moifition n effiiently enhne the tlyti performne of CuO-ZnO-ZrO2/HZSM-5 tlysts. The smple ontining nominl mount of 1% L2O3 54

7 Y. ZHANG et l.: SYNTHESIS OF DME BY CO2 HYDROGENATION Chem. In. Chem. Eng. Q. 23 (1) 4956 (2017) gve the mximum CO2 onversion n DME seletivity of 34.3 n 57.3%, respetively, enefiting from smller Cu prtiles n lrger Cu + /Cu rtio. When the L2O3 ontent is low (from 0.5 to 1%), it n strengthen the intertion etween CuO n other metl oxies n inhiit the reution of CuO speies; menwhile, the totl i mount ereses slightly ut the meium strong i onentrtion n strength inrese little. However, exess of L2O3 ontent, e.g., 2%, will le to n opposite effet. In summry, suitle L2O3 ition n improve the tlyti performne of CuO-ZnO-ZrO2/HZSM-5 for one step CO2 to DME trnsformtion. Aknowlegement The uthors thnk Ntionl Nture Siene Fountion of Chin ( , , n ), SRF for ROCS, SEM (No. [2010]1174), Nturl Siene Fountion of Lioning Provine ( ), Lioning Eutionl Deprtment Fountion (L ), LNET (LJQ ) for finnil support. REFERENCES [1] P. Cox, C. Jones, Siene 321 (2008) [2] S.C.G. Sntos, S.W.M. Mho, A.M. Grrio Peros, M.J.B. Souz, J. Porous Mter. 22 (2015) [3] A. Grí-Treno, A. Vil-Moy, A. Mrtínez, Ctl. Toy 179 (2012) [4] T.A. Semelserger, K.C. Ott, R.L. Borup, H.L. Greene, Appl. Ctl., A: Gen. 309 (2006) [5] G. Bonur, M. Corro, C. Cnnill, A. Mezzpi, L. Spro, F. Aren, F. Fusteri, Ctl. Toy 228 (2014) [6] T. Tkeguhi, K. Yngisw, T. Inui, M. Inoue, Appl. Ctl., A: Gen. 192 (2000) [7] T. Witoo, S.Bumrungslee, M. Chreonpnih, J. Limtrkul, Energy Conv. Mnge. 103 (2015) [8] A. Grí-Treno, A. Mrtínez, Appl. Ctl., A: Gen (2012) [9] T. Witoo, T. Permsirivnih, N. Knjnsoontorn, C. Akkrphtworn, A. Seusi, K. Fungnwkij, C. Wrkulwit, M. Chreonpnih, J. Limtrkul, Ctl. Si. Tehnol. 5 (2015) [10] L. Shi, K. To, R.Q. Yng, F.Z. Meng, C. Xing, N. Tsuki, Appl. Ctl., A: Gen. 401 (2011) [11] P. Go, F. Li, F. K. Xio, N. Zho, W. Wei, L.S. Zhong, Y.H. Sun, Ctl. Toy 194 (2012) 9-15 [12] F. Zh, J. Ding, Y. Chng, J.F. Ding, J.Y. Wng, J. M, In. Eng. Chem. Res. 51 (2012) [13] X.M. Guo, D.S. Mo, G.Z. Lu, S. Wng, G.S. Wu, J. Mol. Ctl., A: Chem. 345 (2011) [14] J. Xio, D.S. Mo, X.M. Guo, J. Yu, Energy Tehnol. 3 (2015) [15] Y.J. Zhng, D.B. Li, Y. Zhng, Y. Co, S.J. Zhng, K.J. Wng, F. Ding, J. Wu, Ctl. Commun. 55 (2014) [16] Y.J. Zhng, D.B. Li, D. Jing, Y. Zhu, Y. Wu, S. Zhng, K. Wng, J. Mol. Ctl. (Chin) 28 (2014) [17] K. Wkui, K. Stoh, G. Sw, K. Shiozw, K. Mtno, K. Suzuki, Y. Yoshimur, T. Hykw, K. Murt, F. Mizukmi, Ctl. Lett. 81 (2002) [18] X.M. Guo, D.S. Mo, G.Z. Lu, S. Wng, G.S. Wu, J. Mol. Ctl., A: Chem. 345 (2011) [19] W.G. Go, H. Wng, Y.H. Wng, W. Guo, M.Y. Ji, J. Rre Erths 31 (2013) [20] P. Go, F. Li, N. Zho, F.K. Xio, W. Wei, L.S. Zhong, Y.H. Sun, Appl. Ctl., A: Gen. 468 (2013) [21] H.J. Zhn, F. Li, P. Go, N. Zho, F.K. Xio, W. Wei, L.S. Zhong, Y.H. Sun, J. Power Soures 251 (2014) [22] G. Bonur, M. Corro, L. Spro, C. Cnnill, F. Aren, F. Frusteri, Appl. Ctl., B: Environ (2013) [23] L. Li, D.S. Mo, J. Yu, X.M. Guo, J. Power Soures 279 (2015) [24] S.G. Li, H.J. Guo, C.R. Luo, H.R. Zhng, L. Xiong, X.D. Chen, L.L. M, Ctl. Lett. 143 (2013) [25] X.M. Guo, D.S. Mo, S. Wng, G.S. Wu, G.Z. Lu, Ctl. Commun. 10 (2009) [26] R. Nie, H. Lei, S. Pn, L. Wng, J. Fei, Z. Hou, Fuel 96 (2012) [27] P. Go, F. Li, H.J. Zhn, N. Zho, F.K. Xio, W. Wei, L.S. Zhong. J. Ctl. 298 (2013) [28] R.W. Liu, Z.Z. Qin, H.B. Ji, T.M. Su, In. Eng. Chem. Res. 5 (2013) [29] Y.W. Zhng, Y.M. Zhou, H. Liu, Y. Wng, Y. Xu, P.C. Wu, Appl. Ctl., A: Gen. 323 (2007) [30] G.P. Jio, Y.J. Ding, H.J. Zhu, X.M. Li, W.D. Dong, J.W. Li, Y. Lv, J. Ctl. (Chin) 30 (2009) [31] C.V. Hilgo, H. Itoh, T. Httori, M. Niw, Y. Murkmi, J. Ctl. 45 (1984) [32] G. Bonur, M. Corro, L. Spro, C. Cnnill, F. Aren, F. Frusteri, Appl. Ctl., B: Environ (2013) [33] Y.Y. Shu, D. M, X.H. Bo, Y. Xu, Ctl. Lett. 66 (2000) [34] X.N. Wng, Z. Zho, C.M. Xu, A.J. Dun, L. Zhng, G.Y. Jing, J. Rre Erths 25 (2007) [35] P.H. Mtter, D.J. Bren, U.S. Ozkn, J. Ctl. 223 (2004) [36] J.M. Cmposmrtin, A. Guerreroruiz, J.L.G. Fierro, J. Ctl. 156 (1995) [37] K.P. Sun, W.W. Lu, F.Y. Qiu, X.L. Xu, Appl. Ctl., A: Gen. 252 (2003) [38] D.S. Mo, W.M. Yng, J.C. Xi, B. Zhng, Q.Y. Song, Q.L. Chen, J. Ctl. 230 (2005) [39] D.G. Cntrell, L.J. Gillie, A.F. Lee, K. Wilson, Appl. Ctl., A: Gen. 287 (2005)

8 Y. ZHANG et l.: SYNTHESIS OF DME BY CO2 HYDROGENATION Chem. In. Chem. Eng. Q. 23 (1) 4956 (2017) YAJING ZHANG 1,3 YU ZHANG 1 FU DING 1,3 KANGJUN WANG 1,3 XIAOLEI WANG 2 BAOJIN REN 1 JING WU 1 1 College of Chemil Engineering, Shenyng University of Chemil Tehnology, Shenyng, Chin 2 Shool of Siene, Shenyng University of Tehnology, Shenyng, Chin 3 Lioning Co-innovtion Center of Fine Chemil Inustry, Shenyng, Chin NAUČNI RAD SINTEZA DIMETIL ETRA HIDROGENIZACIJOM CO2 POMOĆU LA2O3-MODOFOKIVANIH CuO ZnO ZrO2/HZSM-5 KATALIZATORA Oksltnom ko-preipitionom metoom je pripremljen serij ktliztor CuO-ZnO- ZrO2/HZSM-5 moifikovnih pomoću L2O3. Ktliztori su okrkterisni X-ifrkionom metoom (XRD), N2 sorpijom-esorpijom, termoprogrmirnom reukijom (H2-TPR), termoprogrmirnom esorpijom (NH3-TPD) i fotoelektronskom spektroskopijom X-zrk (XPS). Istržen je i utij sržj L2O3 n strukturu i performnse ktliztor. Ktliztori su testirni u proesu CO2 hirogenizije i irektne sinteze imetil etr (DME). Rezultti pokzuju otk L2O3 pooljšv performnse ktliztor, ko i su mksimln konverzij CO2 (34,3%) i DME selektivnost (57,3%) oijeni upotreom ktliztor s 1% L2O3, zog mnjih Cu česti i većeg onos Cu + /Cu 0. Ključne reči: hirogenizij CO2, imetil etr L2O3 promoter. 56