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.