Enhancing the coupling effect in a sandwiched FeNiPS3/graphite catalyst derived from graphite intercalation compounds for efficient oxygen evolution reaction

Abstract

The sluggish kinetics of the oxygen evolution reaction (OER) limits the development of energy transfer technologies such as water splitting and zinc air batteries (ZABs). To this end, a cost-effective and highly active FeNiPS₃/graphite layer (FeNiPS₃/GL) sandwich-structure was designed and prepared by in situ transforming ferric and nickel chloride-based graphite intercalation compounds (GICs) through a solid-state reaction for catalyzing the OER. The obtained sandwich-structured FeNiPS₃/GL catalyst exhibits excellent catalytic performance with a low overpotential of 223 mV, a small Tafel slope of 58 mV dec⁻¹, and durable stability. The outstanding performance of FeNiPS₃/GL may be due to the coupling effect, the sandwich-structure and the active Ni doping that facilitate electron transfer, suppress the aggregation of FeNiPS₃ and expose a massive number of edge active sites for enhancing the intrinsic activity of the catalyst. The FeNiPS₃/GL assembled ZAB also presents durable stability for 175 h and a stable energy efficiency of 61.9% for practical application. Therefore, the sandwich-structured FeNiPS₃/GL optimizes the unexposed active sites, semiconducting nature and the inert basal plate shortages of metal phosphorus trisulfides, and provides a reference value for exploring more metal phosphorus trisulfides through in situ transformation of GICs as efficient catalysts.