Role of catalyst support over PdO–NiO catalysts on catalyst activity and stability for oxy-CO2 reforming of methane Original Research Article

PdO–NiO catalysts over several commercial metal oxides were synthesized using incipient wet impregnation method. The activities of PdO–NiO catalysts for syngas production via oxy-CO2 reforming of methane were investigated at temperatures ranging from 500 °C to 800 °C in a fixed-bed continuous-flow reactor. The PdO–NiO/Y2O3 and PdO–NiO/Al2O3 catalysts show very high CH4 and CO2 conversions due to the formation of metal-support compound on these catalysts. On the PdO–NiO/Y2O3 catalyst, Pd interacts with Y2O3 support to form PdxOyYz compound while Ni interacts with Al2O3 support to form NiAl2O4 spinel compound on the PdO–NiO/Al2O3 catalyst. However, the amount of deposited carbon on the spent PdO–NiO/Y2O3 catalyst is much lower than the one on the PdO–NiO/Al2O3 catalyst due to the presence of surface β-oxygen species and ability of Y2O3 to form oxycarbonate species, resulting in stable catalytic performance without noticeable deactivation during reaction. The surface β-oxygen species are found to promote cracking of C–H bond in CH4 while the oxycarbonate species can oxidize the deposited carbon, respectively, hence leading to the stability of the PdO–NiO/Y2O3 catalyst.