N-doping activated defective Co3O4 as an efficient catalyst for low-temperature methane oxidation

Development of non-noble metal catalyst for low-temperature methane oxidation is extremely important yet is still a challenge. Here, we construct a defective N-doped Co3O4 by a facial N2 plasma engraving method. The obtained catalyst exhibits excellent catalytic activity with methane conversion rate of 6.5 μmol g−1 s-1 at reaction temperature of 342 °C and space velocity of 46,800 mL g−1 h−1, which is about 7.3 times that of pristine Co3O4, and is among the highest active non-noble metal catalyst. The catalyst also shows high stability under hydrothermal environment. By systematic characterization and theory calculations, the superior performance could be attributed to the defective structure, enhanced redox property and highly exposed active sites. Meanwhile, N doping plays significant role in activating Co3O4 by improving the electrophilicity of surface oxygen and lowering C–H bond activation energy. The study will bring significative insight into the design of advanced Co3O4 catalysts for methane oxidation.