Defective C3N4 frameworks coordinated diatomic copper catalyst: Towards mild oxidation of methane to C1 oxygenates

Mild conversion of CH4 to value-added chemicals remains a grand challenge due to its chemical inertness. We report the N-defective C3N4 confined diatomic Cu (Cu2@C3N4-D) catalysts for the efficient oxidation of CH4 to C1 oxygenates at low temperature. With photo-irradiation, the carbon atoms neighbouring defects of C3N4 can anchor the second Cu by Cu-C2N bonding. Cu2@C3N4-D exhibits C1-oxygenates STY up to 4878 mu mol gcat- 1 h-1 with TOF of 83 h-1 at 50 degrees C, which is 300% higher than that of single atomic catalysts and even better than the reported noble-metal catalysts. The catalyst stability is also proved. Both experiments and computations demonstrate that the diatomic Cu pairs are toughly packed in asymmetrical [N3-Cu]center dot center dot center dot[Cu-C2N] with + 1 charge for Cu, endowing the catalyst with unique synergistic effects on CH4 activation. It provides a simple way to construct active sites with well-controlled atom number and enlightens the defect functionalization for catalyst design.

Automated summary

A novel diatomic Cu catalyst, Cu2@C3N4-D, is reported in this study for efficient oxidation of CH4 to C1 oxygenates at low temperature, showing high catalytic activity and stability. The unique structure of the catalyst provides synergistic effects for CH4 activation and offers a new strategy for designing active sites with controlled atom number.