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

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 Ti 3 C 2 O 2 and Ti 4 C 3 O 2. 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 Ti 4 C 3 O 2 has stronger catalytic ability than Ti 3 C 2 O 2. H coverage is negatively correlated with catalytic performance of Ti n+1 C n O 2 (n = 2, 3). Among calculated doping elements, for improving catalytic ability of Ti 3 C 2 O 2 , V or Mo doping is beneficial. While for Ti 4 C 3 O 2 , only Mo doping is beneficial. Furthermore, compression strain of −5%, −3%, −1% is beneficial for improving catalytic performance of Ti 3 C 2 O 2 and Ti 4 C 3 O 2. Our work reveals the microscopic mechanism of MXene catalyzing HER, which is useful for the further development of water electrolysis catalysts. [Display omitted] • Catalytic properties of Tin+1CnO2 (n = 2, 3) were systematically calculated & compared • Ti4C3O2 shows better catalytic performance than Ti3C2O2 • H coverage is negatively correlated with catalytic performance of Tin+1CnO2 (n = 2, 3) • V, Mo for Ti3C2O2, Mo for Ti4C3O2 can improve the catalytic performance • Compression strain of -5%, -3%, -1% is beneficial for Ti3C2O2 and Ti4C3O2 catalysts [ABSTRACT FROM AUTHOR]