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

Dual-site Au/Ta-TiO 2 photocatalyst was designed to photocatalytic oxidative coupling of methane. • The incorporation of Ta as an n-type dopant TiO 2 , promoting the reduction of molecular oxygen to superoxide radicals (O 2 • − ). • Au nanoparticles effectively promoted C C coupling. • Au 1wt% /Ta 0.03 -TiO 2 achieved an ethane production rate of 25 mmol∙g −1 ∙h −1 with a C 2+ selectivity of 83%. 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-TiO 2 photocatalyst that achieves high-performance OCM. The incorporation of Ta as an n-type dopant effectively modulates the electronic structure of TiO 2 , providing abundant localized electrons that promote the reduction of molecular oxygen to superoxide radicals (O 2 • − ). It subsequently participates in the oxidative cycle, ultimately regenerating water and thereby enhancing CH 4 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-TiO 2 catalyst yields a methane conversion rate of 25 mmol∙g −1 ∙h −1 and 83% selectivity towards C 2+ 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. This work designs a Ta-doping and Au-loading dual-site TiO 2 photocatalyst to improve the selective conversion of methane to ethane under aerobic conditions for sustainable chemical production. Download: Download high-res image (133KB) Download: Download full-size image