Application Of NiO And MgO Solid Solution In Catalyzing Bio-oil Steam Reforming To Produce Hydrogen

Since bio-oil has source wide and renewable virtues, catalyzing steam reforming ofbio-oil for hydrogen production has received more and more attentions. In this paper,Ni_xMg_1-xO solid solution based catalysts were used to catalyze steam reforming ofacetic acid for hydrogen production.The solid solution of NiO-MgO, NiO/MgO, NiO-MgO-m and NiO/MgO-m wereprepared by coprecipitation method, impregnation method, CMK-3template methodand mesoporous MgO （marked as MgO-m） immersion method, respectively. And thenthe four solid solution were characterized with XRD, N₂absorption/desorption andH₂-TPR. The reduced Ni/NiO-MgO, Ni/MgO, Ni/NiO-MgO-m and Ni/MgO-mcatalysts were investigated by catalyzing acetic acid steam reforming for producinghydrogen in a fluidized bed reactor. The catalysts and the deposition of coke on eachcatalyst were characterized by XRD, TG, TPO, TPH.The results showed that the BET surface area and pore diameter of mesoporousNiO/MgO-m solid solution which was obtained by the mesoporous MgO-m templatewith nickel nitrate solution were66.0m²/g and4.4nm, respectively. The values werehigher than that of other catalysts solid solution. It was about2.3times for theNiO/MgO solid solution prepared with common MgO. The metal Ni was restored fromNi/Ni_xMg_1-xO catalysts at10%H₂/Ar.To compare the catalytic activity and stability of the catalysts on the steamreforming of acetic acid, the reaction was carried out at550oC with steam-to-HAc（H₂O/HAc） to6, LHSV=5h-1, the catalyst with mesoporous MgO-m carrier relativelyhigh activity and stability,with acetic acid conversion of97.5%, hydrogen selectivity of83.2%and hydrogen yield of2.8mol/mol, respectively was1.1times of Ni/MgOcatalysts. The hydrogen selectivity and hydrogen yield of catalyst with mesoporousMgO-m carrier on the steam reforming of acetic acid was not reduced for20h, still was82.0%and2.7mol/mol. Because of mesoporous MgO catalyst had higher specificsurface area, so Ni particle can be well disperse, reactant and product can be fullydiffusion in the duct of catalyst. Consequently, Ni/Ni_xMg_1-xO catalyst were preparedwith mesoporous MgO exhibited relatively high activity and stability. The results of reacted catalyst showed that The coke on Ni/MgO-m catalyst wasthe least with0.25g/g and that was the reason of activity was relatively steady. thedesposion of coke was C, C_xH_y or C_xH_yOzthe same with carbon on the other catalyst.In concluson, Ni/MgO-m catalyst were prepared with Ni（NO₃）₂that it wasimpregnated into mesoporous MgO carrier exhibited relatively high activity andstability than the other Ni catalysts.