Design and synthesis of ultrathin, layered high surface area nickel hydroxide on reduced graphene oxide electrocatalyst for enhanced HER catalysis

Nickel (Ni) remains the industrial benchmark for the hydrogen evolution reaction (HER) in alkaline electrolysis, but increasing Ni demand highlights the need for catalysts with higher Ni utilization and efficiency. Here, we report a materials engineering strategy for improving Ni atom efficiency by constructing ultrathin, highly dispersed Ni-based electrocatalysts supported on reduced graphene oxide (Ni@rGO). The catalysts are synthesized through a simple and scalable chemical impregnation–reduction approach that enables high Ni loading while maintaining extensive surface accessibility and strong electronic coupling with a conductive rGO scaffold. Structural characterization reveals uniformly distributed Ni(OH) 2 and metallic Ni species forming ultrathin architectures that increase electrochemically accessible surface area and facilitate efficient charge transport. The optimized Ni@rGO500 delivers high activity, achieving geometric current densities of −103 mA cm −2 (RDE) and −119 mA cm −2 (GDE) at −0.3 V RHE, and high mass activities of −1.94 mA μ g Ni − 1 (RDE) and −1.5 mA μ g Ni − 1 (GDE) at −0.3 V RHE, surpassing commercial Ni/C benchmark. Ni@rGO500 also exhibits a higher mass-specific ECSA than commercial Ni/C while retaining comparable specific activity, indicating that its superior mass activity arises primarily from greater electrochemical accessibility of Ni rather than from enhanced intrinsic activity. These results demonstrate that rational control over nanoscale catalyst structure, without compositional modification or dopant incorporation, provides an effective pathway toward resource-efficient Ni-based materials for scalable hydrogen production.