Direct oxidation of methane to oxygenates on supported single Cu atom catalyst

Abstract

Catalytically converting CH4 to chemicals and fuels is of paramount importance but remains a major challenge to simultaneously obtain high activity and selectivity. Here, we report Cu1/ZSM-5 single atom catalyst is highly active (C1 oxygenates productivity of 4800 μmol⋅gcat−1 at 50 °C and 12,000 μmol⋅gcat-1 at 70 °C within 30 min) and selective (C1 oxygenates selectivity of 99 % at 50 °C) for direct CH4 oxidation, comparable to most of those state-of-the-art noble metal catalysts. The combined DFT calculation, electronic microscope, X-ray absorption and electron paramagnetic resonance results confirm that each isolated Cu atom stabilized by four O moieties on the ZSM-5 support possesses uniform Cu1-O4 entity as active site and preferentially activates CH4 instead of CH3OH that is advantageous for highly selective C1 oxygenates production, especially for methanol. Our molecular-level finding on the atomic structure of Cu active site paves the way to design better catalysts for methane conversion.