A highly active and stable hydrogen evolution catalyst based on pyrite-structured cobalt phosphosulfide

TLDR

Hybrid structures with multiple functional components are a promising approach for electrocatalytic hydrogen production, where cost‑effective, active, durable catalysts are needed to replace platinum. The study reports a design and synthesis of a highly active, stable hydrogen evolution catalyst based on pyrite‑structured cobalt phosphosulfide nanoparticles on carbon nanotubes. The catalyst is produced via a three‑step synthesis that imparts conductivity, activity, and stability, with phosphorus substitution enhancing chemical stability and durability, as revealed by X‑ray absorption spectroscopy and computational studies. The catalyst delivers high hydrogen evolution activity, reaching 10 mA cm⁻² and 100 mA cm⁻² at 48 mV and 109 mV overpotentials, and phosphorus substitution provides essential chemical stability and durability.

Abstract

Abstract Rational design and controlled synthesis of hybrid structures comprising multiple components with distinctive functionalities are an intriguing and challenging approach to materials development for important energy applications like electrocatalytic hydrogen production, where there is a great need for cost effective, active and durable catalyst materials to replace the precious platinum. Here we report a structure design and sequential synthesis of a highly active and stable hydrogen evolution electrocatalyst material based on pyrite-structured cobalt phosphosulfide nanoparticles grown on carbon nanotubes. The three synthetic steps in turn render electrical conductivity, catalytic activity and stability to the material. The hybrid material exhibits superior activity for hydrogen evolution, achieving current densities of 10 mA cm −2 and 100 mA cm −2 at overpotentials of 48 mV and 109 mV, respectively. Phosphorus substitution is crucial for the chemical stability and catalytic durability of the material, the molecular origins of which are uncovered by X-ray absorption spectroscopy and computational simulation.