Exploring efficient hydrogen evolution electrocatalysts of nonmetal atom doped Mo2CO2 MXenes by first-principles screening

Non-metal doping engineering has shown great potential for designing high-performance MXene-based catalysts for electrocatalytic hydrogen evolution. We rationally design 14 kinds of nonmetal atom-doped Mo2CO2 catalysts and investigate the effects of nonmetal doping on the thermal stability and hydrogen evolution reaction (HER) catalytic activity of these structures through first-principles calculations. The results show that the addition of nonmetal dopants, such as Si, Cl, Br and I, on the Mo2CO2 surface can effectively improve the HER activity, making them promising candidates for effective HER catalysts. Besides, we studied the thermal stability of nonmetal doped Mo2CO2 by calculating the binding energy and explored the reason behind the variation in the binding energy. Furthermore, the origin of the HER activity difference regulated by various nonmetal dopants is explained based on the analysis of their electronic properties. We found that the number of valence electrons and Bader charge coupling of doped nonmetal atoms are effective electronic descriptors of the hydrogen adsorption strength and HER activity, which provide a clue for future prediction of highly efficient MXene-based HER catalysts.