Promotional effect of alkaline earth over Ni/La2O3 catalysts for hydrogen production via CO2 reforming of methane

Abstract

Alkaline earth metals on Ni-La2O3 have been investigated as promoters for hydrogen production from methane. It was found from O2-TPD, β-oxygen peak was observed on Mg-, Ca- and Sr-doped on La2O3 supports, indicating the presence of oxygen species from bulk surface. Furthermore, an additional g-oxygen peak was also observed on Ca- and Sr-doped indicating presence of oxygen species from lattice. This suggests that the adsorption/desorption ability of La2O3 can be significantly improved by doping Mg, Ca and Sr. Moreover, CO2 adsorption/desorption was also investigated. The results revealed that Ca content shows the highest CO2 adsorption ability, following by Sr, Mg and undoped La2O3. Over 95% methane conversion can be achieved in all alkaline doped catalysts; and about 82% CO2 conversion observed for Ca-doped catalysts. Oxygen mobile species can react with remaining carbon to form COx, resulting in less carbon formation. Therefore, catalytic stability can be improved significantly with Sr content.