Carbon-Embedded Tungsten Carbide Electrocatalysts Derived from Self-Deposited Tungsten Oxide for the pH-Universal Hydrogen Evolution Reaction

Tungsten carbide (WC) has been exploredas a cost-effectiveandEarth-abundant alternative electrocatalyst for the hydrogen evolutionreaction (HER) in both acid and alkaline conditions, due to its electronicstructure comparable to that of platinum. Herein, we report on a simpleand convenient approach for depositing the carbon-embedded WC electrocatalyston nickel foam from the thermal reduction of a sucrose-impregnatedself-deposited tungsten trioxide (WO3) precursor. Differentsucrose concentrations (between 20 and 80% aqueous solution) and reductiontemperatures (between 600 and 1000 degrees C) are tested to achievean optimized material exhibiting the best electrocatalytic efficiencyfor HER. The optimized material is obtained from the precursor impregnatedwith 50% sucrose and thermally reduced at 800 degrees C. It can operateHER with overpotential values measured at 10 and 100 mA cm(-2) of 0.124 and 0.232 V, respectively, at pH 14, and 0.208 and 0.333V at pH 0.3, respectively. Furthermore, these electrodes are foundto be stable in both media during controlled-current density electrolysistests over a period of 40 h. The presence of excess amorphous carbonembedding WC is beneficial to improve the conductivity and dispersibilityof the electrocatalyst and consequently its HER activity. These findingsdemonstrate that robust and efficient WC-based binder-free HER electrocatalystscan be produced easily from spontaneously deposited WO3 film and sucrose as the carbon source.

Automated summary

This article presents a simple and convenient method for depositing carbon-embedded tungsten carbide electrocatalyst on nickel foam. By optimizing the sucrose concentration and reduction temperature, the best electrocatalytic efficiency for the hydrogen evolution reaction (HER) is achieved. The resulting electrocatalyst exhibits stability and efficiency in both acid and alkaline conditions.