Alkaline Water Splitting Using Hafnium-Based Stable and Efficient Bifunctional Electrocatalyst

The desire to achieve sustainable development goals inspired exploring green energy as a favorable alternative to hazardous fossil fuel-based energy. Alkaline water electrolysis is a promising candidate for producing low-cost pure green hydrogen; however, the efficiency of non-precious transitional metal-based catalysts is still behind noble electrocatalysts (like Pt and IrO2). To make hydrogen a next-generation fuel, the replacement of high-cost scarce noble metal is required. An attempt has been made to use a non-precious transitional bimetallic combination of hafnium nickel diselenide/ reduced graphene oxide (HfNiSe2/rGO) for HER, OER, and overall water splitting. HfNiSe2/rGO demonstrated good electrocatalytic performance; for achieving 10 mA/cm(2) of current density, the overpotential requirement is 162 mV for hydrogen evolution reaction (HER) and 320 mV for oxygen evolution reaction (OER) at 20 mA/cm(2) of current density. Similarly, a low Tafel slope is required, 49 mV dec(-1) for HER and 66 mV dec(-1) for OER in 1 M KOH with high stability. HfNiSe2/rGO also showed highly stable activity for overall water splitting, requiring only 1.56 V to attain 10 mA/cm(2) of current density. The result indicates HfNiSe2/rGO is a suitable electrocatalyst for green hydrogen generation because of its ease of production, economical, good activity, and stability towards water splitting.