Enhanced HER activity of transition metal cluster decorated ReS2 monolayer

Two-dimensional material rhenium disulfide (ReS2) has attracted much attention recently as a potential electrochemical catalyst for the Hydrogen Evolution Reaction (HER). The ReS2 monolayer is found to be catalytically inert. The challenge lies in activating the ReS2 monolayer to increase HER output. One of the approaches to this lies in depositing small metal clusters on the monolayer. This paper examines the formation and stability of small metal clusters on 1T distorted ReS2 monolayer using dispersion-corrected Density Functional Theory. Four different kinds of transition metal clusters, viz. Au, Pt, Mo, and Cr are investigated for geometry and binding on the ReS2 monolayer. HER activity of each type of ReS2-supported metal cluster is investigated based on computed free energy. The HER mechanism was investigated for clusters with optimal activity, and it was found that while the ReS2 monolayer follows the Volmer-Heyrovsky route, for the transition metal cluster decorated ReS2, the Volmer-Tafel route is more probable.