Enhancing photocatalytic methane oxidative coupling by dual sites Au loading and Ta-dopant on TiO₂

The photocatalytic oxidative coupling of methane (OCM) offers a promising green route for carbon utilization but is hindered by low conversion rates and over-oxidation. Herein, we engineer a dual-site Au/Ta-TiO₂ photocatalyst that achieves high-performance OCM. The incorporation of Ta as an n-type dopant effectively modulates the electronic structure of TiO₂, providing abundant localized electrons that promote the reduction of molecular oxygen to superoxide radicals (O₂•^-). It subsequently participates in the oxidative cycle, ultimately regenerating water and thereby enhancing CH₄ activation. Meanwhile, Au nanoparticles serve as sites for methyl radical coupling, curbing over-oxidation. The concerted catalysis on these two sites leads to outstanding OCM performance. An optimized Au/Ta-TiO₂ catalyst yields a methane conversion rate of 25 mmol∙g^-1∙h^-1 and 83% selectivity towards C₂₊ products in a flow reactor that exceeds most reported photocatalysts. This work provides new insights into achieving high-performance photocatalytic methane conversion by precisely driving oxygen activation.