Hydrogen production from methanol steam reforming over B-modified CuZnAlO_x catalysts

In this work, CuZnAlO_x (CZA) catalysts prepared by coprecipitation method and a series of yB/CZA catalysts with various boron loadings (y=0.28%, 0.38%, 0.73%, 0.89% and 4.10%) prepared by impregnation method were used in the methanol steam reforming for hydrogen production. In addition, the B-modified CZA catalysts were deeply characterized by different techniques such as ICP, BET, SEM, N₂O chemisorption, TEM, XRD, H₂-TPR and XPS to explore the structure-activity relationship. The characterization results revealed that the introduction primarily affected the Cu dispersion, reductibility and the interaction between the boron and copper species. The 0.38B/CZA catalyst revealed the optimum catalytic performance among the researched catalysts, which were due to the presence of highly dispersed Cu particles and the strong interaction between the boron and copper species. The 93% methanol conversion, the CO selectivity as low as 0.3%, and the long-time stability with 102 h time on stream were obtained over it when the reaction conditions were 250℃, n(H₂O):n(CH₃OH)=3 and GHSV=9000 mL/(g·h).