First‐principles Density Functional Theory Elucidation of the Hydrogen Evolution Reaction on TM‐promoted TiC2 (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 (TiC2). It is found that the adsorption strength of TMs on TiC2 is stronger than that of TMs on γ‐graphyne and weaker than that of TMs on Ti3C2. Among the fifteen investigated catalysts, Ru−TiC2, Ag−TiC2, Ir−TiC2, Au−TiC2, and Fe−TiC2 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−TiC2. This work suggests that Fe−TiC2 is possibly a superior HER electrocatalyst. Electronic properties of fifteen single transition‐metal (TM)‐promoted (TM=Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Cd, Os, Ir, Pt, Au, and Hg) TiC2 are investigated. Ru−TiC2, Ag−TiC2, Ir−TiC2, Au−TiC2, and Fe−TiC2 have hydrogen evolution reaction (HER) overpotential of −0.18, −0.15, −0.18, −0.17, and −0.04 V, respectively. Overall, this study suggests that Fe−TiC2 could be an excellent HER electrocatalyst.