ZnS-stabilized single atoms for highly-efficient water electrolysis

Efficient generation of hydrogen via water electrolysis provides a strategy for producing clean and sustainable fuel. Nevertheless, the sluggish cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) require much energy input to overcome the high overpotential. Rational design of electrocatalysts is of crucial importance for enhancing the HER and OER performance. Herein, metal single atoms stabilized on the ZnS support (M@ZnS) were systematically investigated as the electrocatalysts for HER and OER via the density functional theory (DFT) calculations. Volcano plots were established to screen HER and OER catalysts with excellent performance. The structural, thermodynamic and electrochemical stability of M@ZnS catalysts were investigated. Sn@ZnS and Ni@ZnS exhibit superior HER catalytic activity. In particular, the ΔGH∗ value of Sn@ZnS is 0.049 eV, which is lower than that of the well-known benchmark Pt catalyst. Sn@ZnS and Pt@ZnS show good OER activity, thus they are expected to be the promising OER electrocatalyst candidates. The overpotential values of Sn@ZnS and Pt@ZnS are 0.60 V and 0.42 V, respectively. Sn@ZnS can work as a bifunctional HER/OER electrocatalyst for water electrolysis. This work not only provides theoretical guidance on the design of low-cost electrocatalysts toward HER and OER, but also paves a new way to stabilize single atoms for the fabrication of single-atom catalysts.