Noble-metal-free dye-sensitized selective oxidation of methane to methanol with green light (550 nm)

Developing low-energy input route for conversion of methane (CH₄) to value-added methanol (CH₃OH) at room temperature is important in environment and industry. Bonding in electron donor-acceptor hybrid can potentially promote charge transfer and photocatalytic efficiency of CH₄ conversion. Herein, bonding in electron donor rhodamine B (RhB)–acceptor (TiO₂) hybrid (RhB/TiO₂) significantly promotes the selectivity of photocatalytic oxidation of CH₄ to CH₃OH and utilization of visible light (low-energy photons) at ambient condition. Even under green light irradiation (λ = 550 nm), the noble-metal-free RhB/TiO₂ hybrid synthesized presents enhanced oxidation of CH₄ to CH₃OH with a generation rate of 143 ·mol·g^-1·h^-1 and selectivity of 94%. This work demonstrates the possibility and feasibility of noble-metal-free catalysts for activating CH₄ under visible light at room temperature.