Biogas reforming for hydrogen enrichment by ceria decorated over nickel catalyst supported on titania and alumina

Abstract

Catalytic dry reforming of biogas for hydrogen enrichment was studied over cerium oxide promoted nickel catalysts supported on titanium dioxide and aluminium oxide. The catalysts were prepared by wet impregnation method and characterized by H2-TPR, XRD, BET and FESEM techniques. Their catalytic performance in the biogas dry reforming reaction was studied at temperature ranges from 650 to 850 °C, with a CH4/CO2 ratio of 1.5:1. The H2-TPR results revealed that 11 wt % Ni impregnation on TiO2 support makes the catalyst with strong metal-support interaction which moderates the metal sintering. Also, the addition of CeO2 effectively improved the CH4 and CO2 conversions as well as H2 enrichment. At 850 °C, 11 wt % Ni/TiO2 catalyst leads to 70.5% CH4 conversion with 32.0% H2 enrichment, whereas, Ni0·11/Ce0.20 (Al2O3TiO2) yielded high CH4 conversion (84.9%) with 40.6% of H2 enrichment. No significant change in the activity of the catalyst was observed with 8.8 wt % of carbon deposited on the Ni0·11/Ce0.20 (Al2O3TiO2) catalyst, after 7 h of continuous reforming. Moreover, under combined (dry and oxidative) reforming of biogas, the stoichiometric H2/CO ratio (1.2) was observed at 0.47 O2/CH4 ratios with negligible carbon deposition. Thus, Ni0·11/Ce0.20 (Al2O3TiO2) catalyst exhibited better activity and selectivity with high catalyst stability at 850 °C.