Partial oxidation of methane (CH4) to methanol (CH3OH) remains a great challenge in the field of catalysis due to its low selectivity and productivity. Herein, Ag–O–Ag/graphene and Cu–O–Ag/graphene composite catalysts are proposed to oxidize methane (CH4) to methanol (CH3OH) by using the first-principles calculations. It is shown that reactive oxygen species (μ-O) on both catalysts can activate the C–H bond of CH4, and in addition to CH4 activation, the catalytic activity follows the order of Ag–O–Ag/graphene (singlet) > Ag–O–Ag/graphene (triplet) ≈ Cu–O–Ag/graphene (triplet) > Cu–O–Ag/graphene (singlet). For CH3OH* formation, the catalytic activity follows the order of Cu–O–Ag/graphene (triplet) > Ag–O–Ag/graphene (triplet) > Ag–O–Ag/graphene (singlet) > Cu–O–Ag/graphene (singlet). It can be inferred that the introduction of Cu not only reduces the use of noble metal Ag but also exhibits a catalytic effect comparable to that of the Ag–O–Ag/graphene catalyst. Our findings will provide a new avenue for understanding and designing highly effective catalysts for the direct conversion of CH4 to CH3OH.

Excessive CO2 emission has caused severe greenhouse problems. CO2 reduction reaction (CO2RR) is considered to be a promising strategy to effectively reduce CO2 emission, which not only captures CO2 in...