Selection and performance of cathode materials for ozone decomposition and pollutant mineralization

Electrochemically Assisted Ozonation (EAO) is an emerging advanced technology for water purification that implies electroreduction of externally generated ozone (O3) with the formation of highly reactive species to degrade and mineralize pollutants. However, the extreme conditions and harsh pH levels associated with this process pose significant challenges to the stability and effectiveness of electrodes, making the selection of appropriate materials crucial. This study evaluated various electrode materials—noble metals like platinum (Pt), and palladium (Pd) and non-noble metals like copper (Cu), titanium (Ti), and silver (Ag)—with a focus on their electroactivity, durability, and cost. Preliminary experiments identified Ag and Ti as the most effective cathodes for EAO treatments aimed at paracetamol (PA) mineralization. After a 3-hour treatment, at 400 A m-2, the electrodes ranked as follows: Ag>Ti>Pd>Cu>>Pt. Ag and Ti, as the most promising materials were then tested for their stability over extended service periods through repeated hotoelectr measurements. The results revealed that Ag not only outperformed the other materials, achieving 65 % TOC removal after 3 h at 400 A m-2, but also demonstrated excellent reproducibility and low market costs. These findings suggest that EAO could be a key technology in developing more effective and sustainable water purification solutions.