Hierarchical Zn-Co-P nanoneedle arrays supported on three-dimensional framework as efficient electrocatalysts for hydrogen evolution reaction in alkaline condition

Abstract Currently, the numerous research efforts have focused on the development of efficient non-nobble-metal electrocatalysts toward electrochemical hydrogen evolution reaction (HER) for producing high-purity hydrogen, which has been recognized as a cost-effective and eco-friendly fuel to satisfy global energy demands in the future. Herein, an active HER electrocatalyst based on Zn-Co-P nanoneedle arrays growing directly on the surface of three-dimensional (3D) nickel foam (Zn-Co-P NNs/3D-NF) was successfully synthesized via the simple and low-cost methods. The combination of desired properties for electrocatalysts such as 3D hierarchical nanostructure containing large surface area and abundant electroactive sites for fast diffusion and mass transfer of reactant/electrolyte, highly physical stability for strongly catalytic durability along with the remarkable feature of 1D porous structure of Zn-Co-P NN providing richly active sites for HER resulted in a highly electrocatalytic activity. Interesting, in the introduction of Zn, the Zn-Co-P NNs/3D-NF provides rich edge sites and defects for exposing more active sides, leading to the great enhancing in active surface area, and thereby improving HER catalytic activity. The obtained Zn-Co-P NNs/3D-NF catalyst shown high electrocatalytic efficiency toward HER with the requirement of low overpotential of 138 mV and 210 mV to reach a current density of 10 and 50 mA cm−2 in alkaline media, respectively, together with rapid kinetic at a small Tafel slope of 81.9 mV dec−1. In addition to highly electrocatalytic performance, the Zn-Co-P NNs/3D-NF catalyst also shown the superior durability at −0.138 V, this allowed the production process of H2 to continually occur at least 12 h with retaining a constant current density of 10 mA cm−2. More importantly, our research offered an attractive approach to design non-noble-metal electrocatalysts in the requirement of cost-effectiveness, high catalytic activity, and strong stability for practical HER application.