Electrochemical Peroxodisulfate (PDS) Generation on a Self-Doped TiO 2 Nanotube Array Electrode

Peroxodisulfate (PDS, S 2 O 8 2– ) is one of the strong oxidants ( E °[S 2 O 8 2– /HSO 4 – ] = 2.12 V NHE ), which is widely used for radical polymerization or wastewater treatment. In electrochemical PDS generation, its efficiency highly depends on the •OH generating electrode materials. A boron-doped diamond (BDD) used in electrochemical PDS generation is very expensive prompting the need for new electrode materials for PDS generation. This study reports the self-doped TiO 2 nanotube array electrodes (blue and black TNAs) for PDS generation which are cheap and effective for generating a significant amount of •OH and comparable to BDD electrodes. Blue and black TNA electrodes were excellent for PDS generation exhibiting high current efficiencies for PDS generation (46% and 22%, respectively). Similar to the BDD electrode, it was also confirmed that •OH was the key precursor to the PDS g…