Efficient photocatalytic methane conversion to oxygenates over TiO₂ and Pd co-modified titanium silicalite zeolite

As a type of significant porous materials, molecular sieves possess substantial application potential, particularly for catalysis and sustainability. However, the utilization of molecular sieves for photocatalytic synthesis has been hampered by the low charge transfer and poor photoresponse. Herein, we demonstrate that titanium silicalite (TS) zeolite serves as a versatile support integrated with TiO₂ and Pd for selective photocatalytic methane conversion into oxygenates. Comprehensive characterizations indicate that the pore structures of titanium silicalite zeolite can enhance the adsorption and the localized concentration of reactants for subsequent reactions, while the Pd cocatalyst functions as the photogenerated hole acceptors under light illumination, forming Pd^δ+ species to facilitate the C-H bond cleavage of CH₄ molecules. As a result, the optimal Pd-TS@TiO₂ catalyst achieves a high production rate of 6.8 mmol g⁻¹ h⁻¹ with a selectivity of 96.5% for oxygenate products. This work provides valuable insights into reaction regulation through material design and paves the way for efficient methane conversion to high-value oxygenates.