Pd-Promoted Co2NiO4 with Lattice Co-O-Ni and Interfacial Pd-O Activation for Highly Efficient Methane Oxidation

Abstract

Abstract Nowadays, developing advanced Pd-based catalysts with highly efficient catalytic activity and long-term stability still presents profound challenges. Here, we prepare a novel Pd-Co2NiO4 catalysts with PdOx species simultaneously embedded into Co2NiO4 lattice and decorated on Co2NiO4 surface in high dispersion. The Pd-Co2NiO4 catalysts shows the attractive activity and excellent stability for methane complete oxidation. Based on the experimental and theoretical analysis, the enhanced methane oxidation activity of Pd-Co2NiO4 catalysts is mainly ascribed to two factors. PdOx species incorporated into Co2NiO4 lattice modulates effectively the electronic structure of catalysts, which promotes the electron transfer between Co 3d-O 2p hybrid orbital and Ni eg orbital in Co2NiO4 and thus benefits the activation of adjacent lattice O in Co-O-Ni hybridization, resulting in the rapid migration and activation of lattice oxygen in Co2NiO4 support (Factor I). In addition, the deposition of PdOx species on the Co2NiO4 surface tunes the metal-support interface interactions and promotes the activation of Pd-O bonds, giving rise to more facile CH4 activation ability (Factor Ⅱ). Collectively, the enhanced catalytic properties of the Pd-Co2NiO4 catalysts originated from the activation of lattice oxygen in the Pd-regulated Co-O-Ni hybridization and decorated PdOx sites. This study presented here not only gives further insight into the metal-support electronic interaction, but paves the promising way for the rational fabrication of next-generation environmental catalysts.