Dry reforming of methane over the Ni/Y2O3-ZrO2 catalysts: Effects of the tunable surface oxygen species by modulating the zirconium precursors

Abstract

The surface reactive oxygen species over Y2O3-ZrO2 supports were tuned by regulating the interaction between Y and Zr via modulating the zirconium precursors. It was revealed that the content of the surface adsorbed oxygen species (SAOS) over the catalyst with ZrO2 precursor was the highest, followed by the catalysts with Zr(OH)4 and ZrO(NO3)2·2H2O precursors. The difference of the Y-Zr interaction influenced the reactive oxygen species and the support structure and morphology. However, Ni dispersion was determined by the existence of the isolated Y2O3 due to the enhanced metal-support interaction. High Ni dispersion and abundant surface adsorbed oxygen species were beneficial to promote CH4 and CO2 reactivity. Nevertheless, CH4 dissociation facilitated by the SAOS was more remarkable than CO2 activation at low temperature. Thus, the improvement of the SAOS on carbon-resistant ability of the catalyst was only achieved at high temperature through balancing the carbon formation and elimination.