Influence of MnOx deposition on TiO2 nanotube arrays for electrooxidation

TiO 2 has demonstrated outstanding performance in electrochemical advanced oxidation processes (EAOPs) due to its structural stability and high oxygen overpotential. However, there is still much room for improving its electrochemical activity. Herein, narrow bandgap manganese oxide (MnO x ) was composited with TiO 2 nanotube arrays (TiO 2 NTAs) that in-situ oxidized on porous Ti sponge, forming the MnO x -TiO 2 NTAs anode. XANES and XPS analysis further proved that the composition of MnO x is Mn 2 O 3 . Electrochemical characterizations revealed that increasing the composited concentration of MnO x can improve the conductivity and reduce oxygen evolution potential so as to improve the electrochemical activity of the composited MnO x -TiO 2 NTAs anode. Meanwhile, the optimal degradation rate of benzoic acid (BA) was achieved using MnO x -TiO 2 NTAs with a MnO x concentration of 0.1 mmol L −1 , and the role of MnO x was proposed based on DFT calculation. Additionally, the required electrical energy (EE/O) to destroy BA was optimized by varying the composited concentration of MnO x and the degradation voltage. These quantitative results are of great significance for the design and application of high-performance materials for EAOPs.