A series of Ni/CeO2-ZrO2@SiO2 core-shell catalysts with different mass ratio of shell to core were prepared and utilized to steam reforming of toluene. XRD, SEM, TEM and XPS were applied to characterize the morphology and structure of the catalysts. Results showed that, the catalytic activity of Ni/CeO2-ZrO2@SiO2 was significantly improved compared to Ni/CeO2-ZrO2, the coated SiO2 layer can changed the binding energy of Ni, which modified the activity of Ni and changed the products distribution. The thickness of silica layer was also proved to influence the catalytic performance, core-shell structure with shell-to-core mass ratio of 0.5 showed the highest catalytic activity, its toluene conversion were 62% and 85% respectively under 650℃ and 700℃.
[1] GUAN G Q, KAEWPANHA M, HAO X G, et al. Catalytic steam reforming of biomass tar: prospects and challenges[J]. Renewable and sustainable energy reviews, 2016, 58: 450-461. DOI: 10.1016/j.rser.2015.12.316.
[2] HEIDENREICH S, FOSCOLO P U. New concepts in biomass gasification[J]. Progress in energy and combustion science, 2015, 46: 72-95. DOI: 10.1016/j.pecs.2014.06.002.
[3] ?WIERCZY?SKI D, LIBS S, COURSON C, et al. Steam reforming of tar from a biomass gasification process over Ni/olivine catalyst using toluene as a model compound[J]. Applied catalysis b: environmental, 2007, 74(3/4): 211-222. DOI: 10.1016/j.apcatb.2007.01.017.
[4] HAN J, KIM H. The reduction and control technology of tar during biomass gasification/pyrolysis: an overview[J]. Renewable and sustainable energy reviews, 2008, 12(2): 397-416. DOI: 10.1016/j.rser.2006.07.015.
[5] FURUSAWA T, TSUTSUMI A. Comparison of Co/MgO and Ni/MgO catalysts for the steam reforming of naphthalene as a model compound of tar derived from biomass gasification[J]. Applied catalysis a: general, 2005, 278(2): 207-212. DOI: 10.1016/j.apcata.2004.09.035.
[6] OH G, PARK S Y, SEO M W, et al. Ni/Ru-Mn/Al2O3 catalysts for steam reforming of toluene as model biomass tar[J]. Renewable energy, 2016, 86: 841-847. DOI: 10.1016/j.renene.2015.09.013.
[7] ANIS S, ZAINAL Z A. Tar reduction in biomass producer gas via mechanical, catalytic and thermal methods: a review[J]. Renewable and sustainable energy reviews, 2011, 15(5): 2355-2377. DOI: 10.1016/j.rser. 2011.02.018.
[8] ZHANG R Q, WANG H J, HOU X X. Catalytic reforming of toluene as tar model compound: effect of Ce and Ce-Mg promoter using Ni/olivine catalyst[J]. Chemosphere, 2014, 97: 40-46. DOI: 10.1016/j.chemosphere. 2013.10.087.
[9] NOICHI H, UDDIN A, SASAOKA E. Steam reforming of naphthalene as model biomass tar over iron-aluminum and iron-zirconium oxide catalyst catalysts[J]. Fuel processing technology, 2010, 91(11): 1609-1616. DOI: 10.1016/j.fuproc.2010.06.009.
[10] KONG M, FEI J H, WANG S A, et al. Influence of supports on catalytic behavior of nickel catalysts in carbon dioxide reforming of toluene as a model compound of tar from biomass gasification[J]. Bioresource technology, 2011, 102(2): 2004-2008. DOI: 10.1016/j.biortech.2010. 09.054.
[11] YOON S J, KIM Y K, LEE J G. Catalytic oxidation of biomass tar over platinum and ruthenium catalysts[J]. Industrial & engineering chemistry research, 2011, 50(4): 2445-2451. DOI: 10.1021/ie1020365.
[12] NOGUEIRA F G E, ASSAF P G M, CARVALHO H W P, et al. Catalytic steam reforming of acetic acid as a model compound of bio-oil[J]. Applied catalysis b: environmental, 2014, 160-161: 188-199. DOI: 10.1016/j. apcatb.2014.05.024.
[13] LI C S, HIRABAYASHI D, SUZUKI K. Development of new nickel based catalyst for biomass tar steam reforming producing H2-rich syngas[J]. Fuel processing technology, 2009, 90(6): 790-796. DOI: 10.1016/j.fuproc. 2009.02.007.
[14] CHAN F L, TANKSALE A. Review of recent developments in Ni-based catalysts for biomass gasification[J]. Renewable and sustainable energy reviews, 2014, 38: 428-438. DOI: 10.1016/j.rser.2014.06.011.
[15] SHEN Y F, CHEN M D, SUN T H, et al. Catalytic reforming of pyrolysis tar over metallic nickel nanoparticles embedded in pyrochar[J]. Fuel, 2015, 159: 570-579. DOI: 10.1016/j.fuel.2015.07.007.
[16] MICHEL R, ?AMACZ A, KRZTON A, et al. Steam reforming of α-methylnaphthalene as a model tar compound over olivine and olivine supported nickel[J]. Fuel, 2013, 109: 653-660. DOI: 10.1016/j.fuel.2013.03.017.
[17] LAOSIRIPOJANA N, SUTTHISRIPOK W, CHAROJROCHKUL S, et al. Development of Ni-Fe bimetallic based catalysts for biomass tar cracking/ reforming: effects of catalyst support and co-fed reactants on tar conversion characteristics[J]. Fuel processing technology, 2014, 127: 26-32. DOI: 10.1016/j.fuproc.2014.06.015.
[18] PARK H J, PARK S H, SOHN J M, et al. Steam reforming of biomass gasification tar using benzene as a model compound over various Ni supported metal oxide catalysts[J]. Bioresource technology, 2010, 101(S1): S101-S103. DOI: 10.1016/j.biortech.2009.03.036.
[19] KIMURA T, MIYAZAWA T, NISHIKAWA J, et al. Development of Ni catalysts for tar removal by steam gasification of biomass[J]. Applied catalysis b: environmental, 2006, 68(3/4): 160-170. DOI: 10.1016/j.apcatb.2006.08.007.
[20] ZHU H Y, XUE M W, CHEN H, et al. Dispersion of nano nickel particles over sba-15 modified by carbon films on pore walls[J]. Catalysis letters, 2010, 134(1/2): 93-101. DOI: 10.1007/s10562-009-0229-z.
[21] WANG C G, WANG T J, MA L L, et al. Steam reforming of biomass raw fuel gas over NiO-MgO solid solution cordierite monolith catalyst[J]. Energy conversion and management, 2010, 51(3): 446-451. DOI: 10.1016/j. enconman.2009.10.006.
[22] COURSON C, UDRON L, ?WIERCZY?SKI D, et al. Hydrogen production from biomass gasification on nickel catalysts: tests for dry reforming of methane[J]. Catalysis today, 2002, 76(1): 75-86. DOI: 10.1016/S0920-5861(02) 00202-X.
[23] 施培超, 陈天虎, 张先龙, 等. 生物质焦油组分甲苯在镍/凹凸棒石上的二氧化碳催化重整[J]. 催化学报, 2010, 31(10): 1281-1285. DOI: 10.3724/SP.1.1088.2010. 00329.
[24] BASAGIANNIS A C, VERYKIOS X E. Reforming reactions of acetic acid on nickel catalysts over a wide temperature range[J]. Applied catalysis a: general, 2006, 308: 182-193. DOI: 10.1016/j.apcata.2006.04.024.
[25] SUN F M, YAN C F, WANG Z D, et al. Ni/Ce-Zr-O catalyst for high CO2 conversion during reverse water gas shift reaction (RWGS)[J]. International journal of hydrogen energy, 2015, 40(46): 15985-15993. DOI: 10.1016/j.ijhydene.2015.10.004.
[26] GROSVENOR A P, BIESINGER M C, SMART R S C, et al. New interpretations of XPS spectra of nickel metal and oxides[J]. Surface science, 2006, 600(9): 1771-1779. DOI: 10.1016/j.susc.2006.01.041.
[27] OEMAR U, ANG M L, HIDAJAT K, et al. Enhancing performance of Ni/La2O3 catalyst by Sr-modification for steam reforming of toluene as model compound of biomass tar[J]. RSC advances, 2015, 5(23): 17834-17842. DOI: 10.1039/C4RA16983B.
[28] YAN C F, CHENG F F, HU R R. Hydrogen production from catalytic steam reforming of bio-oil aqueous fraction over Ni/CeO2-ZrO2 catalysts[J]. International journal of hydrogen energy, 2010, 35(21): 11693-11699. DOI: 10.1016/j.ijhydene.2010.08.083.
[29] LIU P, RODRIGUEZ J A. Water-gas-shift reaction on metal nanoparticles and surfaces[J]. The journal of chemical physics, 2007, 126(16): 164705. DOI: 10.1063/1.2722747.
[30] RODRIGUEZ J A, GRACIANI J, EVANS J, et al. Water-Gas Shift reaction on a highly active inverse CeOx/Cu(111) catalyst: unique role of ceria nanoparticles[J]. Angewandte chemie international edition, 2009, 48(43): 8047-8050. DOI: 10.1002/anie.200903918.
