Fabrication of cobalt doped titania for enhanced oxygen evolution reaction

Due to poor electron mobility, early transition metal oxides typically, are not known to catalyze water electroxidation. Here we report the modulation of electrocatalytic properties of pristine anatase by the doping of an earth-abundant metal (Co). So obtained hybrid materials show enhanced catalytic activity for oxygen evolution reaction (OER). It was noted that the retention of free carbon during the synthesis of such hybrid materials further enhances their OER activity bringing it at par with the benchmark IrO2 catalyst. Evaporation induced self-assembly (EISA) was used to prepare mesoporous titania using a triblock copolymer (P123) as structure directing agent. Nanostructured titania was first impregnated with a cobalt complex followed by thermal treatment at 500, 700 and 900 degrees C under air, argon and hydrogen atmosphere to obtain a series of catalysts. The effect of metal content and annealing atmosphere was studied on the composition and OER activity of the catalysts. The best OER activity (.: 440mV@10 mA.cm(-2)), comparable to benchmark IrO2 and decent stability was noted for the material annealed under argon and containing 15 wt % Co. Improved OER activity was attributed to better water adsorption, charge transfer and conductivity of titania upon Co doping and carbon retention.