ABSTRACT
In this work, hydrogen production from glycerol by steam reforming was studied using Ni-metal oxide catalysts. Ni-based catalyst becomes deactivated during steam reforming reactions because of coke deposits and sintering. Therefore, the aim of this study was to reduce carbon deposits and sintering on the catalyst surface by adding a promoter. Ni-metal oxide catalysts supported on Al2O3 were prepared via impregnation method, and the calcined catalyst was reduced under H2 flow for 2 h prior to the reaction. The characteristics of the catalysts were examined by XRD, TPR, TGA, and SEM. The Ni-Fe-Ce/Al2O3 catalyst, which contained less than 2 wt% Ce, showed the highest hydrogen selectivity and glycerol conversion. Further analysis of the catalysts revealed that the Ni-Fe-Ce/Al2O3 catalyst required a lower reduction temperature and produced minimum carbon deposit.
Subject(s)
Aluminum Oxide/chemistry , Cerium/chemistry , Glycerol/chemistry , Iron/chemistry , Nickel/chemistry , Steam , Catalysis , Hydrogen/chemistryABSTRACT
In this work, hydrogen production from glycerol by Steam Reforming (SR) was studied by Ni-Ce catalysts supported on LaAlO3 perovskite in order to effect of the cerium loading amount and the reaction conditions. Nano size Ni-Ce/LaAlO3 catalysts were prepared by precipitation method. The structure of the catalysts was characterized by XRD analysis. The morphology, dispersion and the reduction properties of catalysts was examined by SEM, TEM, H2-chemisorption and TPR, respectively. It was found that 15 wt% Ni-5 wt% Ce/LaAlO3 catalyst showed the highest glycerol conversion and hydrogen selectivity. In addition, the catalyst also showed the high carbon dioxide selectivity and the lowest methane selectivity. The results indicate that the catalyst promotes methane reforming reaction. The highest activity in the 15 wt% Ni-5 wt% Ce/LaAlO3 was attributed to the proper cerium loading amount. Moreover, the lowest metal crystal size and rise in active site were found to have an effect on catalytic activity and hydrogen selectivity. The 15 wt% Ni-5 wt% Ce/LaAlO3 catalyst exhibited excellent performance with respect to hydrogen production at reaction temperature of 450 degrees C, at atmospheric pressure, 20 wt% glycerol solution and GHSV = 6,000 mL/g-cat x hr.
