Electrochemically enhanced activation of Co3O4/TiO2 nanotube array anode for persulfate toward high catalytic activity, low energy consumption, and long lifespan performance

Advanced oxidation processes (AOPs) can directly degrade and mineralize organic pollutants (OPs) in water by generating reactive oxygen species with strong oxidizing ability. The development of advanced electrode materials with high catalytic performance, low energy consumption, no secondary pollution, and long lifespan has become a challenge that must be addressed in this field. A heterojunction catalyst loaded with Co3O4 on TDNAs (Co3O4/RTDNAs) was designed and constructed by a simple and efficient pyrolysis (Co3O4/TDNAs) and electrochemical reduction. Co3O4 can be uniformly distributed on the inner wall and surface of the TiO2 nanotubes, enhancing the specific surface area while forming a tight conductive interface with TiO2. This facilitates rapid transmission of electrons, thereby assisting Co3O4 in quickly activating PS to form reactive oxygen species. The Ti3+ and Ov generated in Co3O4/RTDNAs can significantly improve the electrocatalytic degradation of OPs. Also, the interface formed by Co3O4 and RTDNAs will effectively suppress Co2+ leakage, thereby reducing the risk of secondary pollution. When the reaction conditions were 1 mM PMS (PDS) and a current density of 5 mA/cm2 in the EA-PMS (PDS)/Co3O4/RTDNA system, 30 mg/L TC can achieve 83.24 % (81.89 %) removal in 120 min, with very low cobalt ion leaching, while the energy consumption was reduced significantly. Therefore, EA-PS/Co3O4/RTDNA system has strong stability and a high potential for treating the OPs in AOPs.