Morphology engineering induces the increase of FeP/CoP heterointerface density for efficient alkaline water splitting driven by interfacial dual active sites

Abstract

Developing heterogeneous electrocatalysts with high-efficiency performances toward alkaline water splitting (AWS) is extremely urgent and challenging for the green hydrogen economy. In this work, density functional theory (DFT) calculations revealed that Fe and Co atoms at the FeP/CoP heterogeneous interface act as interface dual active sites to synergistically accelerate AWS. Therefore, the heterointerface density becomes a non-negligible factor affecting the AWS performance. Given this, we innovatively increase the density of the FeP/CoP heterointerface by controlling the size and surface curvature of the phosphide, thereby increasing the number of interfacial dual active sites. Driven by the abundant interfacial dual active sites, FeP/CoP nano-mulberries (FeP/CoP NMs) display a promising AWS performance requiring a voltage of 1.530 V at 10 mA cm⁻² along with exceptional durability up to 1000 h. This work points out a novel direction for enhancing the electrocatalytic performance of heterostructure catalysts.