Strong synergy in a lichen-like RuCu nanosheet boosts the direct methane oxidation to methanol

Abstract The direct methane (CH4) conversion (DMC) to methanol (CH3OH) has been attracting great attention, however it remains a huge challenge to achieve this process because of the dilemmas in CH4 selective activation. We here report that the lichen-like RuCu nanosheets (RuxCu1-x NLs) can serve as high-efficiency catalysts to catalyze DMC to produce oxygenates (CH3OH and methylhydroperoxide (CH3OOH)) under mild conditions in the presence of oxygen (O2) and trace amount of hydrogen peroxide (H2O2). Detailed characterizations and results show that the composition-dependent synergy between Ru and Cu in the bimetallic RuCu NLs, which is related to the ratio of Ru4+ on the surface of catalysts, can strongly enhance the DMC activity. The optimized catalyst of Ru0.85Cu0.15 NLs/SiO2-300 gives superior DMC performance in terms of oxygenates yield (3241.6 μmol g-1 h-1) and selectivity (93.8%) at 50 °C. This work not only highlights the superior performance of DMC from RuxCu1-x NLs, but also promotes the potential application of Ru-based nanomaterials in heterogeneous catalysis.