Effect of synthesis pH on the electrocatalytic activity of RuxSey prepared by the microwave polyol process for oxygen reduction reaction (ORR)

The electrocatalytic conversion for the direct four electron reduction of oxygen to water is extremely important in the clean energy industry. In fuel cells, Pt supported on carbon is usually used as the catalyst for the electroreduction of oxygen. Depolarization of the Pt cathode in direct methanol fuel cells, due to methanol crossover, results in considerable voltage losses [1]. RuxSey nanoparticles have a reasonable high catalytic activity and methanol-tolerance for ORR [2]. In this paper uniform RuxSey chalcogenide electrocatalyst supported on carbon (Vulcan, XC-72R) was prepared by the microwave assisted polyol process, in which an ethylene glycol solution of ruthenium (III) chloride and sodium selenite are heated under microwave [3]. It was found that the RuxSey characteristics including reaction yield, particle size and electrochemical activity for ORR are highly dependent on pH of the synthesis medium. Rotating disk electrode (RDE) voltammetry was carried out to evaluate the electrocatalytic activity of the RuxSey chalcogenide catalyst.