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

• A defective and N-doped Co 3 O 4 exposed with (110) facets is synthesized. • The obtained catalyst shows excellent activity for methane oxidation reaction. • The defective structure faciliates Co 3 O 4 with abundant active surface oxygen. • N doping plays important role of enhancing the C–H bond activation ability. 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 Co 3 O 4 by a facial N 2 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 Co 3 O 4 , 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 Co 3 O 4 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 Co 3 O 4 catalysts for methane oxidation. [ABSTRACT FROM AUTHOR]