Characterization And Electrocatalytic Properties Of Ti/Sb-SnO₂ Electrodes Containing Different Inter Layers For Phenol

Electrochemical catalytic oxidation, which can produce OH?, is an advanced oxidation technology and an effective means to deal with toxic and harmful wastewater. Many electrodes have been used in dealing with organic waste, such as Ti/SnO₂, Ti/PbO₂, Ti/RuO₂, Ti/IrO₂ and so on. Ti/SnO₂ electrode has caused great concern to researchers because of its high oxygen evolution potential and good electrocatalytic activity for organic waste. But Ti/SnO₂ electrode's service life is short, so it is difficult to be applied in industry. Phenol and its derivatives are the main components of wastewater which are expelled from industry, and are a typical representative of organic pollutants. Therefore, this paper is committed to developing an efficient, cheap and stable electrode which has long service life and good electrocatalytic activity for phenol compounds.This paper has prepared Ti/Sb-SnO₂ electrodes with Ni, Co and Mn (doped with different) middle layers, and find out the best doping of Ni, Co and Mn by comparing the effect of electrocatalytic activity for phenol. Then the electrode performance testing and characteriza- tion of Ti/Sb-SnO₂ electrode with Ni, Co and Mn (doped with the best containing) middle layers have been done. The results show that, the best containing of Ni, Co and Mn are all 2%.The order of the electrocatalytic activity of electrodes with Ni, Co and Mn (doped with the best containing) middle layers is Ti/Ni/Sb-SnO₂> Ti/Co/Sb-SnO₂> Ti/Mn/Sb-SnO₂. The service life of Ti/Mn/Sb-SnO₂ is long to 289h, much longer than the Ti/Co/Sb-SnO₂ and Ti/Ni/Sb-SnO₂ electrodes. SEM, XRD and LSV show that the surface of Ti/Mn/Sb-SnO₂ is dense, which can cover the surface of Ti substrate. The average size of the crystal of Ti/Ni/Sb-SnO₂ electrode is small, which cause that the real surface area of Ti/Ni/Sb-SnO₂ electrode is big and the number of active adsorption point is more; the oxygen evolution potential of Ti/Ni/Sb-SnO₂ electrode is high, which is beneficial to the electrocatalytic reaction.Based on the previous experiments, Ti/Co-Ni/Sb-SnO₂ electrode and Ti/Mn-Ni/Sb-SnO₂ electrode have been prepared by thermal oxidation. After 4h, the phenol and COD removal efficiency of Ti/Mn-Ni/Sb-SnO₂ electrode reach 93.86%, which correspond to Ti/Sb-SnO₂ electrode. The degradation on Ti/Mn-Ni/Sb-SnO₂ electrode is worse, and the phenol and COD removal efficiency only reach 52.5% after 4h. The service life of Ti/Mn-Ni/Sb-SnO₂ is 270h, which is longer than the life of Ti/Co-Ni/Sb-SnO₂ and Ti/Sb-SnO₂. SEM, XRD and LSV show that the surface of Ti/Mn-Ni/Sb-SnO₂ is dense, which can cover the surface of Ti substrate, and there is no Ti element present on the surface of the electrode. The average size of the crystal of Ti/Mn-Ni/Sb-SnO₂ electrode is small, and the oxygen evolution potential is higher.The UV spectroscopic study shows that the electrolyzing produces of phenol at different times on Ti/Mn-Ni/Sb-SnO₂ electrode first is quinone, then CO₂ and H2O which are produced after the benzene rings opened.