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

Abstract 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 IrO 2 ). 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 (HfNiSe 2 /rGO) for HER, OER, and overall water splitting. HfNiSe 2 /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. HfNiSe 2 /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 HfNiSe 2 /rGO is a suitable electrocatalyst for green hydrogen generation because of its ease of production, economical, good activity, and stability towards water splitting.