Constructing heterostructure of WP/WP2 to enhance catalytic activity and stability toward hydrogen generation

Abstract

Transition metal phosphides (TMPs) have been identified as potential electrocatalysts for the hydrogen evolution reaction (HER) due to their unique structural and electronic properties. However, TMPs have not yet achieved the desired HER performance, and further improvements are required. Herein, we fabricate heterostructured tungsten phosphide/tungsten diphosphide (WP/WP2) composite microrods grown on carbon cloth (WP/WP2/CC) as an efficient self-supported electrocatalyst, which is proven to be highly efficient and stable for the HER. Various experimental results and density functional theory calculations reveal that the formation of WP/WP2 heterostructures can regulate the electronic structure of active sites and optimize hydrogen adsorption free energy on active sites, which accelerates the electron transfer and boosts the HER performance to WP/WP2/CC. By tuning the phosphidation temperatures, the optimized WP/WP2/CC electrocatalyst shows a superior HER performance with low overpotentials of 92 mV and 146 mV at 10 mA cm−2 in 0.5 M H2SO4 and 1.0 M KOH solutions. Meanwhile, it maintains a stable activity at 100 and 150 mV for at least 12 h in 0.5 M H2SO4 and 1.0 M KOH media, respectively. This study demonstrates that the construction of heterostructures can serve as an efficient strategy to improve the electrocatalytic performance of metal phosphide-based electrocatalysts.