Vertically Aligned Binder-Free ZnO Nanorods on Ni-Foam (ZNr@NF) for Efficient Alkaline Water Electrolysis

Alkaline water electrolysis (AWE) assisted by renewable solar or wind power has become a viable and environmentally beneficial approach for producing green hydrogen on a commercial scale. However, the AWE process requires an active, cost-effective, and stable catalyst to overcome the problems associated with the sluggish reaction kinetics. Here, we present a binder-free, facile, one-step hydrothermal process for synthesizing vertically aligned ZnO nanorods of different aspect ratios on nickel foam (ZNr@NF) as an electrocatalyst. The synthesized optimal ZNr@NF-3 shows an overpotential of 412, 394, 271, 219, and 157 mV in different electrolyte solutions, i.e., neutral BS, 0.05 0.1, 0.5, and 1 M KOH, respectively. In optimum pH electrolyte (1 M KOH), ZNr@NF-3 provides an electrochemically active surface area of 204.50 cm2, and the Tafel slope is ∼109 mV dec–1. It substantiates the presence of more active sites on ZNr@NF-3, contributing to fast reaction kinetics with a turnover frequency (TOF) of ∼8.02 × 10–2H2/scm2 at 157 mV overpotential. Further, the chronopotentiometry test signifies a stable performance of the synthesized electrocatalyst ZNr@NF-3 for the hydrogen evolution reaction. Thus, the present investigation suggests that ZNr@NF-3 may be a feasible and cost-effective electrocatalyst for green hydrogen production through the AWE process.