Influence of doped elements on the property of manganese mixed oxide anode for oxygen production by electrolyzing seawater

Anode materials for hydrogen production by electrolyzing seawater were investigated. The electrodes with γ-MnO₂ type oxide coatings were prepared by anodic electrodeposition on the base of Ti/IrO₂. MnV, MnCr, MnMoFe and MnFeV electrodes were obtained by doping other elements in electrodeposition solution. The results of testing in simulated seawater indicated that the doped elements obviously enhanced the selective performance of electrodes for evolving oxygen and restraining chlorine. The oxygen evolution efficiency of MnFeV was as high as 100%, which can meet the requirement of selectivity in electrolyzing seawater. The results of structure analysis show that a mix-oxide Mn(Fe, V)O₂ with γ-MnO₂ structure was formed after adding Cr, Fe and V to the manganese oxide electrodes. These elements existed in Mn(Fe,V)O₂ in the form of Mn⁴⁺, V⁵⁺, and Fe³⁺. The doped Fe and V can refine grains and increase the deformation energy, thus the electrocatalystic properties for evolving oxygen of electrodes were improved effectively.