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 µmol·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.