Role of catalyst support over PdO–NiO catalysts on catalyst activity and stability for oxy-CO 2 reforming of methane

Abstract

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-CO 2 reforming of methane were investigated at temperatures ranging from 500 °C to 800 °C in a fixed-bed continuous-flow reactor. The PdO–NiO/Y 2O 3 and PdO–NiO/Al 2O 3 catalysts show very high CH 4 and CO 2 conversions due to the formation of metal-support compound on these catalysts. On the PdO–NiO/Y 2O 3 catalyst, Pd interacts with Y 2O 3 support to form Pd x O y Y z compound while Ni interacts with Al 2O 3 support to form NiAl 2O 4 spinel compound on the PdO–NiO/Al 2O 3 catalyst. However, the amount of deposited carbon on the spent PdO–NiO/Y 2O 3 catalyst is much lower than the one on the PdO–NiO/Al 2O 3 catalyst due to the presence of surface β-oxygen species and ability of Y 2O 3 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 CH 4 while the oxycarbonate species can oxidize the deposited carbon, respectively, hence leading to the stability of the PdO–NiO/Y 2O 3 catalyst.