Electrochemical Synthesis of Tungsten Oxide in Chloride Solutions for Environmental Photocatalysis

Abstrac

t—The electrochemical behavior of tungsten in chloride electrolytes with various cationic compositions (Na⁺, K⁺, Li⁺, \({\text{NH}}_{4}^{ + }\)) under the action of pulse alternating current is studied. The decisive influence of the nature of the electrolyte on the phase composition of the resulting dispersed products is shown. The use of NH₄Cl provides the formation of pure crystalline WO₃ with a particle sized 30–35 nm. The photoelectrochemical activity of the synthesized WO₃ in a sulfuric acid medium under simulated solar radiation is studied. The addition of glycerol to H₂SO₄ causes a cathodic shift in the oxidation onset potential by 0.25 V and a three-fold increase in the maximal photocurrent density. The WO₃/FTO-photoanode as part of a flow-through photocatalytic fuel cell (with glycerol as fuel and air-breathing Pt/C-cathode) showed excellent stability in acidic environment and the maximal power density of 64.0 μW cm^–2.