Effect of annealing temperature on Structure and Performance of Nano Ti/IrO2/MnO2 Electrode by Anodic Deposition for Oxygen Evolution

摘要

Nano MnO2 coating was electrochemically deposited on Ti/IrO2 substrate in 1M MnSO4 +0.5M H2SO4 solution of 98 ℃ Field emission scanning electron microscopes (FESEM) showed the as-deposited MnO2 coating consisted of mass of nano γ-MnO2 chips, with a thickness of 5-12nm, a width of 30-50nm and a length of about 100nm. Thermogravimetric and differential scanning calorimetry (TGA/DSC) studied dehydration and oxidation of nano MnO2 coating as a function of annealing temperature. Energy dispersive spectroscopy (EDS) measured the chemical formula of samples annealed at different temperatures, it was as follows: (a) as-deposited: MnO1.50 · 0.65H2O, (b) 200℃: MnO1.64, (c) 300℃: MnO1.945, (d) 400 : ℃ MnO1.946, (e) 500-700 : Mn ℃ 2O3. The physical phases of the as-deposited MnO2 coatings annealed at different temperatures were identified by X-ray diffraction (XRD). The Pr (De Wolff defect) and Tw (Microtwinning defect) of samples were analyzed by the model of Chabre and Pannetier. Cyclic voltammetry (CV) has been used to investigate the electrochemical behavior of the Ti/IrO2/MnO2 electrodes in acid solution. The accelerated lifetime test was measured in 0.5M H2SO4 solution at 40 with a constant anodic current density of 2A ℃ /cm2. The as-deposited Ti/IrO2/MnO2 anode prepared by anodic deposition has the highest service life of 300h.