Self-Supportive Mesoporous Ni/Co/Fe Phosphosulfide Nanorods Derived from Novel Hydrothermal Electrodeposition as a Highly Efficient Electrocatalyst for Overall Water Splitting.

Abstract

Low cost and highly efficient bifuctional catalysts for overall water electrolysis have drawn considerable interests over the past several decades. Here, rationally synthesized mesoporous nanorods of nickel-cobalt-iron-sulfur-phosphorus composites are tightly self-supported on Ni foam as a high-performance, low cost, and stable bifunctional electrocatalyst for water electrolysis. The targeted designing and rational fabrication give rise to the nanorod-like morphology with large surface area and excellent conductivity. The NiCoFe-PS nanorod/NF can reach 10 mA cm-2 at a small overpotential of 195 mV with a Tafel slope of 40.3 mV dec-1 for the oxygen evolution reaction and 97.8 mV with 51.8 mV dec-1 for the hydrogen evolution reaction. Thus, this bifunctional catalyst shows low potentials of 1.52 and 1.76 V at 10 and 50 mA cm-2 toward overall water splitting with excellent stability for over 200 h, which are superior to most non-noble metal-based bifunctional electrocatalysts recently. This work provides a new strategy to fabricate multiple metal-P/S composites with the mesoporous nanorod-like structure as bifunctional catalysts for overall water splitting.