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

Abstract

Electrochemical water splitting is a new approach toward sustainable energy sources. Developing nonprecious watersplitting 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/cm 2 . 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/cm 2 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 H 2 production electrolyzers offers no difficulty in material synthesis, and the electrolyzer assembly can facilitate the development of a clean, renewable energy infrastructure.

Wastewater Utilization as a Source for Green Energy Generation Using Alkaline Water Splitting

“…The suggested electrocatalyst was effectively prepared by using an effective hydrothermal process, and our earlier works detail its numerous advanced characterization outcomes …”

“…However, their high cost and rareness have prevented further commercialization. , Hence, developing non-noble-metal-based catalysts with high activity and stability is essential. In this background, our earlier research discovered the applicability of hafnium-based transitional metal electrocatalysts with remarkable potential for alkaline water electrolysis applications. , The second challenging task is replacing pure water with wastewater for electrolysis applications. Every day, tons of wastewater are generated worldwide, and no single treatment can reduce the water’s contaminants to the permitted limits.…”

Enhancing Trifunctional Electrocatalytic Activities via Lanthanide Modulation in Fe–Co-Based Double Perovskite Oxides

“…), H 2 is being used as an ideal energy vector, thanks to its mobility and storable nature. , Due to the high energy demand (for the strong OO bond formation) and complex four-electron transfer process (sluggish kinetics) of oxygen evolution reaction (OER, the oxidative half-cell), electrochemical H 2 generation (through hydrogen evolution reaction, HER) from complete water splitting on the industrial scale is still limited. Worthy progress for the past few decades had been made in developing a technology with robust, efficient, and durable electrocatalyst for overall water splitting. , Although due to excellent activity along with moderate stability, especially in aqueous medium, RuO 2 and IrO 2 set a benchmark as OER catalysts, but the high cost and low abundance of these noble metals limit their large-scale usage; even cheap earth-abundant electrocatalysts are being looked up for replacement.…”