Synthesis of Co-Doped Tungsten Phosphide Nanoparticles Supported on Carbon Supports as High-Efficiency HER Catalysts

Tungsten phosphide (WP) is believed to be a promising electrocatalyst in the electrochemical hydrogen evolution reaction (HER) for its unique catalytic performances. Nevertheless, its further application is severely limited by the agglomeration caused by the high preparation temperature (over 600 °C). Herein, we adopt a citric acid-guided two-stage aging method to prepare Co-doped WP with small particle size and higher dispersity on the surface of seven different carbon supports. Co is successfully incorporated into the lattice of WP, causing preferable catalytic performance. The introduction of seven different carbon supports enhances electronic metal-supported interaction and proves this two-stage aging method universal. The as-derived CoWP-CA/KB (two-step aging) featured a low overpotential of 111 mV to achieve a current density of 10 mA cm^–2, along with a desirable Tafel slope of 58 mV dec^–1, outperforming most of the WP-based electrocatalysts. Besides, the electrode possesses excellent stability for 60 h without significant attenuation. Its remarkable performance results from its structure (delicate particle size, uniform dispersion, and large specific surface area) and its electrocatalytic properties (large electrochemically active surface area, excellent electrical conductivity, enhanced interfacial charge transfer kinetics, and high turnover frequency). This novel synthesis strategy will be pivotal for designing robust non-noble metal-based electrocatalysts with high HER activity and durability to meet the future keen demand for hydrogen.