(418a) Investigation of Highly Nanoporous Metal Oxide Catalysts Via Nano-Template Synthesis for Oxygen Evolution Reaction

Over the decades, the generation of electricity using renewable energy such as photovoltaic (PV), wind, etc. is sorely expanded through the whole world by the national policies. For example, in Germany, PV-generated power covered approximately 7.2% (40 TWh) of the nation’s net electricity consumption in 2017. As increasing the portion of renewable electricity, the role of power-to-gas (PtG) has been attracting great attention to store the excess electricity and to balance the grid, which can convert the electricity to hydrogen or methane. Recently, proton exchange membrane water electrolysis (PEMWE) has been developing due to the high current operation and excellent load-following characteristics compared to the alkaline water electrolysis for the PtG. Among the electrocatalytic reaction of the PEMWE, the oxygen evolution reaction (OER) at the anode displayed a significantly high overpotential. Thus, the catalysts for OER has been widely developed for several decades to improve the total efficiency of PEMWE. In this presentation, nanoporous RuO_x-based binary catalysts were synthesized by a nano-template method, using the ordered mesoporous silica material as a template and were investigated to improve the activity and stability for OER. Through this method, the nanoporous OER catalysts with a very high surface area over than 100 m²/g were achieved. To investigate the effect of a secondary element in the RuO_x oxide, Ir and Sn were incorporated in the initial preparation stage. In half cell test, OER activity and stability were evaluated by an over-potential at 10mA/cm² and by using galvanic mode, respectively. Synthesized IrRuOx and SnRuOx catalysts displays both very small over-potential of 0.26 V at 10mA/cm², whichindicates the addition of the second metal in the nanoporous RuOx catalyst is improved the activity towards for OER under acidic condition. These catalysts showed superior OER activity compared with the commercial RuO₂ sample