Transition metal doping for enhanced decoupled water splitting through the h-WO3 auxiliary electrode

Efficient H₂ production is an actual global problem. Decoupled water splitting is the most efficient method for H₂ industrial production. Among the many electrolyzer configurations, the recently proposed single-cell acid electrolyzer with pseudocapacitive WO₃-based auxiliary electrodes is a promising way to generate H₂ and O₂ temporarily and spatially decoupled without membranes or expensive materials. The performances of this device are related to WO₃ electrochemical properties. In this work, hexagonal WO₃ were produced by using hydrothermal synthesis both pure and Co, Cr, Ni, Mo and Ti (5 % at.) doped with the aim to improve WO₃ pseudocapacity. Structural and morphological properties of obtained materials were investigated as well as the electrochemical behavior of the related electrodes. It resulted that by doping h-WO₃ with Ti and Mo ions the specific capacity increased from 477.04 F/g of pure h-WO₃ to 636.94 F/g and 657.75 F/g, respectively.