Robust NiCoP/CoP Heterostructures for Highly Efficient Hydrogen Evolution Electrocatalysis in Alkaline Solution

Electrocatalytic hydrogen evolution reaction, the cornerstone of the emerging hydrogen economy, can be essentially facilitated by robustly heterostructural electrocatalysts. Herein, we report a highly active and stably heterostructural electrocatalyst consisting of NiCoP nanowires decorated with CoP nanoparticles on a nickel foam (NiCoP-CoP/NF) for effective hydrogen evolution. The CoP nanoparticles are strongly interfaced with NiCoP nanowires producing abundant electrocatalytically active sites. Combined with the integrated catalyst design, NiCoP-CoP/NF affords a remarkable hydrogen evolution performance in terms of high activity, enhanced kinetics, and outstanding durability in an alkaline electrolyte, superior to most of the Co (or Ni)-phosphide-based catalysts reported previously. Density functional theory calculations demonstrate that there is an interfacial effect between NiCoP and CoP, which allows a preferable hydrogen adsorption and thus contributes to the significantly enhanced performance. Furthermore, an electrolyzer employing NiCoP-CoP/NF as the cathode and RuO₂/NF as the anode (NiCoP-CoP/NF||RuO₂/NF) exhibits excellent water-splitting activity and outstanding durability, which is comparable to that of the benchmark Pt-C/NF||RuO₂/NF electrolyzer.