Structure Design And Performance Study Of Bimetallic Perovskite Catalyst Based On Ethanol Steam Reforming

Hydrogen is an ideal energy source with high efficiency and cleanliness.The development of hydrogen energy must first solve the problem of low-cost and large-scale hydrogen production.Among the many technical routes,hydrogen production by steam reforming of bio-oil is remarkable because of its high conversion efficiency and wide source of raw materials.Ethanol is an important bio-oil model.Therefore,we can systematically study the reaction of ethanol steam reforming（ESR）to understand the mechanism of bio-oil hydrogen production.ESR reaction requires active and stable catalysts for hydrogen production.Ni-based catalysts have strong C-C bond breaking ability and catalytic activity,they are commonly used catalysts for ethanol steam reforming.However,sintering and carbon deposition often lead to the deactivation of Ni-based catalysts.In this paper,two types of active metal-doped perovskite catalysts are designed and prepared.One is a La_0.8Ce_0.2Mn_0.6Ni_0.4O₃（LCMN@Ni）catalyst with Ni particles exsolved,and LCMN@Ni/Cu is obtained by Cu loaded on this basis.The second is a high specific surface area La_0.6Ca_0.4Fe_0.8Ni_0.2O₃（LCFN）nanofiber catalyst prepared by electrostatic spinning technology.These catalysts was reduced to gain exsolved nano-active metal particles on the surface.Due to the strong interaction between the nanoparticles and the matrix,they can effectively suppress the sintering of active metals and carbon deposition,and can significantly improve the long-term performance stability of the catalyst.The main research contents are as follows:（1）The catalytic activity and performance stability of two LCMN@Ni and LCMN@Ni/Cu catalysts in ESR reactions were studied.Due to the high catalytic activity of the nano-Ni particles exsolved in the matrix,ethanol can be completely converted and maintain the high selectivity of H₂ and CO.At 700°C,the former presented a hydrogen selectivity of74%and the latter presented a H₂selectivity of 73%.The performance of LCMN@Ni catalyst remained stable during the 30 h catalytic test.In contrast,the LCMN@Ni/Cu bimetal catalyst exhibited more excellent chemical stability and resistance to carbon deposition.（2）The influence of the structural characteristics of the LCFN catalyst on its catalytic performance was studied.Through reduction at 700°C for 1 h under 5%H₂/N₂ atmosphere,a porous fiber-structured R1-LCFN catalyst was obtained.A large number of fine Ni-Fe alloy particles were exsolved on the surface of the perovskite substrate.In the ESR tests at500～700°C,the catalyst obtained ethanol conversion of 100%and H₂ selectivity of about70%.In the reforming reaction at 500°C,the test showed good catalytic performance stability in 20 h.