Photocatalytic conversion of methane selectively into oxygenated products in the presence of chloride ions

•A considerable productivity and selectivity of methanol (180.75 μmol·gcat−1·h−1, 80.07 %) are achieved.•Cl− could be transformed into Cl over BiOCl-Ov to efficiently activate methane.•The in situ produced Cl is constrained on the surface of BiOCl-Ov, inhibiting over halogenation.•Reactive oxygen species produced by H2O2 dissociation are utilized to be the receptors of CH3.