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.