Water splitting for hydrogen production using a high surface area RuO_2 electrocatalyst synthesized in supercritical water

摘要

In water electrolysis, a major obstacle is the anodic reaction for water oxidation where substantial energy loss occurs mainly due to the large overpotential. Therefore, the elec-trocatalytic material of an anode is of importance to achieve a highly efficient water splitting reaction. Among the various requirements, the surface area of electrocatalysts has been considered a key factor in electrocatalytic reactions. In this study, to obtain a high surface area RuO_2 electrocatalyst, a supercritical hydrothermal synthetic method was applied. Indeed, RuO_2 particles with the surface area of 78.2 m~2/g were successfully synthesized, which is 7 times higher compared with the commercial version. We also investigated the electrocatalytic activity of the synthesized high surface area RuO_2 by evaluating the number of active sites and hydrogen production rates and compared them with the commercial one as a reference. Based on the cyclic voltammetric measurements, the number of active sites was estimated to be 152.1 mC cm~2 and 17.0 mC cm~2 for the synthetic and the commercial RuO_2, respectively. More importantly, the hydrogen production rates measured by the water splitting device with RuO_2 films for the anode showed 4 times higher value for the synthetic RuO_2 compared with the commercial one.