Charge-carrier enrichment type-dependent product selectivity in methane photooxidation

Selective photocatalytic oxidation of methane to value-added C1 oxygenates under mild conditions is attractive but remains limited by poor control over branching selectivity, because methanol and formaldehyde share closely related energetics and pathways. Here we demonstrate programmable selectivity in methane photooxidation by steering the dominant type of photogenerated charge carriers at metal/boron nitride (BN) interfaces. Carrier enrichment at the active sites dictates the hydrogen-transfer steps that govern the fate of a common hydroxymethyl intermediate, enabling selective switching between methanol and formaldehyde. We propose that electron-enriched AuNPs/BN facilitates hydroxymethyl intermediate hydrogenation to methanol, whereas hole-accumulating PdSA/BN promotes hydroxymethyl intermediate dehydrogenation to formaldehyde. Under atmospheric pressure, PdSA/BN gives formaldehyde with ~90% selectivity and generation rate of 1653.75 μmol·g−1·h−1, while AuNPs/BN achieves ~92% selective methanol production at 1070.17 μmol·g−1·h−1. Here, we show that establishing carrier-polarity programming at heterogeneous interfaces as a general strategy to control branching selectivity in photocatalytic C-H oxidation. Charge-carrier enrichment at active sites enable type-dependent product selectivity in methane photooxidation: electron-enriched AuNPs/BN favors methanol selectivity ( ~ 92%), while hole-enriched PdSA/BN favors formaldehyde selectivity ( ~ 90%).