Continuous flow photosynthesis of methanol from methane by plasmonic charge accumulation

Direct oxidation of methane (CH₄) to methanol (CH₃OH) typically requires elevated temperatures and pressures, making it challenging to achieve high yield and selectivity under mild conditions. Here, we show a surface plasmon-mediated catalyst designing strategy based on the synergy between Pd nanoparticles and ZnO nanosheets. When applied in a continuous gas-solid-liquid photocatalytic flow system at low temperature and ambient pressure, the optimized catalyst achieves a CH₃OH productivity of 6584 μmol g⁻¹ h⁻¹, which is competitive with reported photocatalytic systems, along with selectivity of ~100% and sustained stability over 100 h. In-situ characterization and theoretical calculations indicate that plasmon-induced electron accumulation suppresses over-oxidation and promotes high CH₃OH selectivity. This work offers a pathway to efficient, selective CH₄ photo-oxidation using plasmonic catalyst design, supporting the sustainable utilization of solar energy.