Theoretical studies on chemisorption of oxygen on β-Mo2C catalyst and its surface oxidation

► We study oxygen chemisorption on β-Mo2C surface and its oxidation by DFT. ► (101) surface is more active than the (011) surface towards oxygen adsorption. ► (011) surface can be covered by 1/2 or 7/8 ML oxygen. ► (101) surface can be fully oxidized to be 1 ML by oxygen. ► Low temperature and high oxidant pressure favor the surface oxidation.