The Research On Electrocatalyst Material Of OER For Water Electrolysis Under Acidic Medium

Hydrogen is a kind of clean, efficient and extensive sources energy, and is considered to be an ideal energy carrier in the future. As far as we know, there are many methods to produce hydrogen. The Solid polymer electrolyte (SPE) water electrolysis technology, which provides several advantages over traditional technologies including higher energy efficiency, environmental friendly, higher production rates, higher purity, better safety and more compact design, will play more and more important role in water electrolysis industry; however, higher cost limits its further application.Mesoporous TiO2 are used as anode catalyst support for SPE water electrolysis in this work for purpose of reducing noble metal oxide catalyst loading and improving catalytic activity, and then the effects of TiO2 surface microstructure and different catalyst loading on catalyst are studied. Otherwise, the influence of heat treatment and W, Ta doping process on the carrier and catalyst were discussed.The composite catalysts were synthesized on the surface of different TiO2 support by using a modified version of the Adams fusion method and H2IrCl6·6H2O was used as raw materials. The samples were characterized by BET, XRD, SEM, TEM, cyclic voltammetry and electrochemical testing. (1).The results suggest that the lower specific surface area of supports, the smaller the ohmic resistance, the greater the active area of the catalyst, the better the performance of the catalyst in the single cell. Utilization of the TiO2 support resulted in a reduction in the size of the IrO2 crystallites and improve the distribution of IrO2 catalyst. (2).The investigation of W doped support that have been heat treated show that the charge-transfer resistance is lower, when W element doping concentration is 10at%. The W element is helpful to the charge transfer between the reactants and 40I-Ti0.9W0.1O2-2 has the maximum catalytic activity area with great durability and stability. Samples with different IrO2 loading capacity were prepared and Ti0.9W0.1O2-2 was used as the carrier. The 60I-Ti0.9W0.1O2-2 sample showed a polarization potential of 1.832V under a current density of 1Acm-2 which is much lower than that of pure IrO2. (3).The test results of Ta doping experiments indicate that the precipitation of Ta2O5 in the carrier is helpful to the charge transfer between carrier and catalyst, the ohmic resistance of the catalyst decreased, the charge transfer resistance lower, and the catalytic activity turns better. In addition, a 40wt% composite catalyst with active material loading of 2.5mg/cm2 leads to catalyst layer become too thick, which limits the contact of catalyst and reactant; and then result in a worse performance in the electrolyzer cell.