Fabrication of Stepped CeO2 Nanoislands for Efficient Photocatalytic Methane Coupling

Nonoxidative conversion of methane (NOCM) under mildconditionsis a highly desirable technology for the low-carbon and atom-economicalproduction of H-2 and value-added chemicals. Here, we reportthe fabrication of CeO2 nanoisland patterns on the surfaceof Ce-Zr solid solutions. These ultrasmall CeO2 nanoislandswith abundant step-edge structures provide unprecedented methane adsorptionand activation, achieving the highest methane conversion rate of 1517 & mu;mol g(-1) h(-1) for photocatalyticNOCM to date. Density functional theory calculations revealed thatthe low-coordinated Ce-O units at the stepped CeO2(111) surface possess more open planar configurations, which facilitatethe cleavage of methane C-H bonds via a distinct metal-CH4 & sigma;-complex mechanism that is energetically more favorablethan the radical-like mechanism on the flat CeO2(111) surface.Moreover, the photocatalyst demonstrated a reversible and cooperativephotoactivation process that enables the transition from the restingstate to the active state, thereby enhancingthe photoexcited charge separation efficiency and photocatalytic NOCMactivities.

Automated summary

A highly desirable technology for the low-carbon and atom-economical production of H2 and value-added chemicals, nonoxidative conversion of methane (NOCM) under mild conditions was achieved using CeO2 nanoisland patterns on the surface of Ce-Zr solid solutions. These patterns facilitated methane adsorption and activation, leading to the highest methane conversion rate for photocatalytic NOCM to date. The photocatalyst also demonstrated a reversible and cooperative photoactivation process, enhancing its photoexcited charge separation efficiency and photocatalytic NOCM activities.