Fabricating macroporous RuO2-TiO2 electrodes using polystyrene templates for high chlorine evolution efficiencies

In dimensionally stable anodes, RuO2-TiO2 has emerged as one of the fundamental anode materials in terms of practical application because of its high stability and catalytic performance toward chlorine evolution. Nevertheless, high chlorine evolution efficiency is still required for an effective chlorine production process. In this study, high chlorine electrocatalytic active RuO2-TiO2 electrodes were fabricated using several ranges of polystyrene microsphere templates (0.1, 0.46 and 1.1 mu m) resulting in novel three-dimensional ordered macroporous structures. Higher chlorine evolution efficiency was observed in the macroporous RuO2-TiO2 electrodes than that in the nontemplated electrode at the same Ru loadings. In particular, a macroporous electrode fabricated with a specific polystyrene size (0.46 mu m) exhibited the highest chlorine evolution efficiency in this study indicating the existence of an optimal macropore size for RuO2-TiO2 electrodes in the chlorine evolution reaction. This chlorine evolution efficiency could be attributed to the well-developed outer active surface area formed by the optimal pore structure which contributes to the easy mass transfer of chloride ions and removal of produced chlorine gas bubbles. This novel idea strategically provides a new method for preparing inexpensive RuO2-TiO2 electrocatalysts with a high electrochemically active surface area, especially the outer active surface area for chlorine evolution.