HfCoS/rGO Bifunctional Electrocatalysts for Efficient Water Splitting in Alkaline Media

Electrochemical water splitting is a new approach toward sustainable energy sources. Developing nonprecious water-splitting electrocatalysts has attracted interest recently. On the other hand, nonprecious electrocatalysts excellent in oxygen and hydrogen evolution reactions are extremely limited and challenging. An efficient nanomaterial combination of hafnium cobalt sulfide/reduced graphene oxide (HfCoS/rGO) electrocatalyst was synthesized by hydrothermal synthesis. The proposed electrocatalyst was studied for electrocatalytic activity. The synthesized electrocatalyst showed excellent performance for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Low overpotentials of 164 and 210 mV for the HER and OER, respectively, are needed to achieve 10 mA/cm2. Similarly, smaller Tafel slopes of 49 and 46 mV/dec are required for the HER and OER, respectively, with long-term stability in alkaline media (1 M KOH). Utilizing a HfCoS/rGO bifunctional nonprecious electrocatalyst, a water-splitting electrolyzer can produce a current density of 10 mA/cm2 using 1.60 V. Another outstanding result highlighted their enhanced catalytic activity, as evidenced by their long-term stability at various potentials. Developing efficient and economical H2 production electrolyzers offers no difficulty in material synthesis, and the electrolyzer assembly can facilitate the development of a clean, renewable energy infrastructure.