Nanocrystalline manganese-molybdenum-tungsten oxide anodes for oxygen evolution in acidic seawater electrolysis

In an attempt to tailor new oxygen evolution anodes for acidic seawater electrolysis, manganese-molybdenum-tungsten oxide anodes were prepared by anodic deposition on IrO2/Ti substrate using 0.2 kmol m(-1) MnSO4-(0.00-0.006) kmol m(-3) Na2MoO4-(0.0-0.03) kmol m(-3) Na2WO4 electrolytes at pH -0.1 similar to+1.0 and 363 K at 600 Am-2. The deposits consist of a nanocrystalline single gamma-MnO2 type phase in the form of triple Mn1-x-yMoxWyO2+x+y oxide. Anodic deposition in 0.2 kmol m(-3) Mn2+-0.003 kmol m(-3) MO6+-0.006 kmol m(-3) W6+ electrolyte at pH 0.0 resulted in the formation of an electrode with 100 % and 99.8 % oxygen evolution efficiencies before and after electrolysis for 691.2 ks in 0.5 kmol m(-3) NaCl solution of pH 2 at 1000 Am-2. Thus, Mn1-x-yMoxWyO2+x+y electrodes were promising oxygen evolving anodes for acidic seawater electrolysis. It has been concluded that additions of both tungsten and molybdenum beneficially bring about an increase in the real electro-catalytic activity along with the formation of deposits with optimum thickness and good adherence to the IrO2/Ti Substrate.