First-principles Density Functional Theory Elucidation of the Hydrogen Evolution Reaction on TM-promoted TiC 2 (TM=Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au).

Single-atom-catalyst-based systems have been attractive by virtue of their desirable catalytic performance. Herein, the possibility of the 15 transition-metal (TM)-promoted (TM=Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Cd, Os, Ir, Pt, Au, and Hg) and their hydrogen evolution reaction (HER) performance were investigated on two-dimensional titanium carbides (TiC 2 ). It is found that the adsorption strength of TMs on TiC 2 is stronger than that of TMs on γ-graphyne and weaker than that of TMs on Ti 3 C 2 . Among the fifteen investigated catalysts, Ru-TiC 2 , Ag-TiC 2 , Ir-TiC 2 , Au-TiC 2 , and Fe-TiC 2 exhibits overpotential of -0.18, -0.15, -0.18, -0.17, and -0.04 V, respectively. In addition, the Volmer-Tafel step was preferred to the Volmer-Heyrovsky step on Fe-TiC 2 . This work suggests that Fe-TiC 2 is possibly a superior HER electrocatalyst.