Preparation, characterization, and electrochemical behavior of a novel porous Magnéli phase Ti4O7-coated Ti electrode

Although Magnéli phase Ti4O7 has been recognized as one of the most promising anode materials for electrochemical advanced oxidation process (EAOP), the current density is still not uniformly distributed on the large-sized Ti4O7 bulk electrode due to its relatively poor conductivity, which leads to rapid deterioration and damage of the electrode. Therefore, the development of Ti4O7 coated metal electrode on a large scale with low cost is of great significance for its industrial applications. Here we report for the first time that Ti4O7-coated Ti electrode is successfully prepared by sintering the brushed TiO2 coating on Ti substrate. The microstructure and electrochemical behavior of the electrode were also investigated. Results show that the continuous and porous Magnéli phase Ti4O7 coating well bonded with the substrate can be fabricated by sintering the pre-coated TiO2 with the thickness of 78–200 μm on Ti substrate at 1000 °C for 1 h under a flowing argon atmosphere. The electrochemical stability window of the Ti4O7-coated Ti electrode in 1 M NaCl solution is more than 4.2 V. Additionally, the refractory organic ethylene glycol butyl ether is effectively degraded on the Ti4O7-coated Ti electrode. The CODcr decreases from 18000 mg L−1 to 82 mg L−1 and the removal rate of CODcr reaches 99.54% after electrolysis for 24 h.