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.