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

Abstract

Developing low-energy input route for conversion of methane (CH 4 ) to value-added methanol (CH 3 OH) at room temperature is important in environment and industry. Bonding in electron donor-acceptor hybrid can potentially promote charge transfer and photocatalytic efficiency of CH 4 conversion. Herein, bonding in electron donor rhodamine B (RhB)-acceptor (TiO 2 ) hybrid (RhB/TiO 2 ) significantly promotes the selectivity of photocatalytic oxidation of CH 4 to CH 3 OH and utilization of visible light (low-energy photons) at ambient condition. Even under green light irradiation ( λ = 550 nm), the noble-metal-free RhB/TiO 2 hybrid synthesized presents enhanced oxidation of CH 4 to CH 3 OH 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 CH 4 under visible light at room temperature.