Engineering hierarchical NiFe-layered double hydroxides derived phosphosulfide for high-efficiency hydrogen evolving electrocatalysis

Exploring robust, highly efficient, and cost-effective non-noble metal electrocatalysts for replacing Pt in hydrogen evolution reaction (HER) is of great significance. In this study, we skillfully synthesized binary transition-metal (i.e., nickel and iron) phosphosulfides on nickel foam (NiFeSP/NF) via a sulfuration/phosphorization treatment of bimetallic layered double hydroxides (LDH). Taking the advantage of the presence of active heterointerfaces among Ni2P, Ni3S2, and FeS2, the NiFeSP/NF catalyst, which was advantageous of the highly exposed active sites, exhibited an extraordinary catalytic activity in HER-an overpotential of 70 mV at a current density of 10 mA cm(-2) and a Tafel slope of 69 mV dec(-1), outperforming most of the existing counterparts. Moreover, NiFeSP/NF catalysts demonstrated favorable long-term catalytic stability for 10 h. We contributed this superior catalytic activity to the characteristic attributes of NiFeSP/NF, which could be stemmed from its exquisite catalyst design: (i) the co-occurrence of highly HER-favored crystalline Ni2P, Ni3S2, and FeS2 in bimetallic phosphosulfides and (ii) the existence of multi-functional phase interfaces among Ni2P, Ni3S2, and FeS2 in the NiFeSP/NF hierarchical structure. The present study exemplified an effective strategy for designing HER-favored bimetallic phosphosulfides and provided the scientific base for the insight into the catalytic nature of multi metallic phosphosulfides. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.