Doping and strain effect on the catalytic performance of Tin+1CnO2 (n = 2, 3) for hydrogen evolution reaction

Abstract

Mxenes has attracted wide attention due to its advantages of high conductivity, diverse composition, thinness and adjustable structure. In this paper, we systematically calculated adsorption energy, Gibbs free energy, and exchange current density of Ti3C2O2 and Ti4C3O2. The effect of H-coverage, element (Cr, Hf, Mo, Nb, Ta, V) doping and strain application on the HER catalytic performance were also analyzed. The results show that Ti4C3O2 has stronger catalytic ability than Ti3C2O2. H coverage is negatively correlated with catalytic performance of Tin+1CnO2 (n = 2, 3). Among calculated doping elements, for improving catalytic ability of Ti3C2O2, V or Mo doping is beneficial. While for Ti4C3O2, only Mo doping is beneficial. Furthermore, compression strain of −5%, −3%, −1% is beneficial for improving catalytic performance of Ti3C2O2 and Ti4C3O2. Our work reveals the microscopic mechanism of MXene catalyzing HER, which is useful for the further development of water electrolysis catalysts.