Synergistic effect of Cu and Fe on g-C3N4 for selective oxidation of methane to C1 products

The selective conversion of methane is a significant but difficult challenge. We reported a CuFe bimetallic catalyst supported by g-C3N4 for the catalytic oxidation of methane to oxygenated C1 products. Using H2O2 as the oxidant, Cu0.4Fe0.3-C3N4 catalyst had a C1 yield of 8231 mu mol center dot gcat almost all of the liquid phase products were target C1 products. The methanol selectivity on CuFe-C3N4 was 44.5 %, comparing with 20.2 % methanol selectivity on Cu-C3N4. The formation of a Cu-O-Fe site on the CuFe-C3N4 was confirmed by in situ DRIFTS and 57Fe Mo<spacing diaeresis>ssbauer spectroscopy. This Cu-O-Fe site was responsible for the improved catalyst performance. DFT calculations illustrated that at the Cu-O-Fe site, H2O2 dissociated into two center dot OH radicals instead of center dot H and center dot OOH radicals as it did at the Cu-O-Cu site. The center dot OH radicals combined with the center dot CH3 radicals from the CH4 molecules to form methanol. These findings provided valuable insights into the rational design of active sites on carbon nitride materials.