Selective Photocatalytic Oxidative Ethane Dehydrogenation on AuPd Nanoparticle-Decorated TiO2

Photocatalytic oxidative dehydrogenation of ethane offers a promising approach for producing ethylene under mild conditions. However, achieving high ethylene yields and selectivity is challenging due to the high C-H bond activation barrier in ethane and the tendency for overoxidation to CO2. In this study, we demonstrate that TiO2 with highly dispersed AuPd nanoparticles serves as an efficient and selective photocatalyst for the dehydrogenation of ethane with O2 in a flow reactor. The optimized Au0.33Pd0.67/TiO2 achieves up to 20.3 mmol g-1 h-1 of ethylene with 91.5% selectivity, resulting in a 5.9% apparent quantum efficiency at 365 nm. Detailed characterizations reveal that the Au0.33Pd0.67 cocatalyst plays a crucial role in facilitating photocarrier separation and regulating the formation of active oxygen species. Au0.33Pd0.67 effectively activates lattice oxygen of TiO2, which serves as the localized oxidant to promote ethane dissociation through a photoassisted Mars-van Krevelen mechanism. Additionally, Au0.33Pd0.67/TiO2 facilitates dioxygen reduction and ensures rapid oxygen replenishment in the TiO2 lattice, thereby achieving a high yield of ethylene formation. This work provides valuable insights for designing composite photocatalysts for efficient and selective ethane oxidative dehydrogenation.