Synthesis of multifunctional Ti/RuO2-ZnO composite catalytic electrodes for electrochemical oxidation and hydrogen production from toluene-containing wastewater

Developing electrodes that effectively perform indirect oxidation on nondecomposable organic compounds is a key objective in electrochemical oxidation research. This study focuses on fabricating a Ti/RuO2-ZnO electrode through a simple pyrolysis method on a Ti substrate etched with hydrochloric acid. Hydrochloric acid etching played a pivotal role in enhancing coating stability by markedly increasing the Ti substrate's surface area and hydrophilicity. Analyzing the linear sweep voltammetry revealed that the electrode exhibited a low overvoltage of the oxygen evolution reaction, reaching 221 mV at 10 mA cm(-2), indicating effective use as an active anode. The electrode's performance was evaluated by removing toluene contained in a 0.1 M NaCl solution at pH 5. The electrochemical reaction generated active chlorine in the solution, oxidizing 98.66 % of toluene over 3 h and concurrently producing 25.62 mL of hydrogen. This study presents a simple and effective synthesis of a RuO2-based active anode, demonstrating its potential application not only in removing toluene from wastewater but also in hydrogen production.