A Novel Water Oxidation Catalyst Made By the Facile Deposition of Ruthenium on Graphene Oxide

Abstract

As populations grow worldwide, there is an ever-increasing need for sustainable and renewable energy sources to keep up with the high demand of energy. One promising technology is electrochemical water-splitting, which creates hydrogen and oxygen at the cathode and anode, respectively. Developing viable, stable catalysts for water splitting is critical since this reaction is truly a green, sustainable method to generate hydrogen fuel. However, more active electrocatalysts for the water oxidation reaction (WOR) are needed to improve the viability of this technology. Currently, these catalysts are most often composed of rare and expensive earth metals such as iridium. More sustainable materials such as those based on ruthenium have been recently investigated as alternatives to the rare metal systems. Ruthenium-based materials are an ideal choice as Ru offers multiple available oxidation states to help facilitate the water-splitting reaction and possibly lower overpotentials[1]. However, many ruthenium-based materials are prone to stability issues in acidic media at high over potentials. In addition, sluggish kinetics are often observed [2]. In this work we synthesized graphene oxide, via a simple and low-cost method, and utilized it as a support for the Ru oxide nanocatalyst[3]. We used graphene oxide due it high mechanical strength, favorable electronic properties, and the ease at which it can be doped with metals[4]. Ruthenium oxide nanoparticles were deposited on the surface of the graphene oxide at a 5wt% metal loading by a facile method. The materials were examined electrochemically in acidic media for the water oxidation reaction, where we observed low overpotentials and high stability during prolonged testing. This simple preparation method could be used to efficiently synthesize active and highly stable water-oxidation catalysts that are more cost-effective. This novel ruthenium stabilized on graphene catalyst could aid in the future development of more sustainable materials for the future of renewable energy technology.