Electrocatalytic Hydrogenation of Toluene Using a Proton Exchange Membrane Reactor

In order to develop an efficient and greener method for organic chemical hydride production in the energy carrier system, the electrocatalytic hydrogenation of toluene to methylcyclohexane was carried out using a proton exchange membrane (PEM) reactor, which generally applied a polymer electrolyte fuel cell and industrial electrolysis technologies. The electrochemical conversion proceeded in high current efficiencies (>90%) under sufficiently mild conditions with various metal-supported catalysts such as Pt/C, Rh/C, Ru/C, and PtRu/C. For example, methylcyclohexane was obtained in 94% current efficiency by the electrochemical hydrogenation of toluene with PtRu/C. Although the current efficiency of the hydrogenation with Pt/C, Rh/C, and Ru/C apparently decreased under high current density conditions due to the side reaction (hydrogen evolution), the hydrogenation with PtRu/C catalysts proceeded in excellent efficiencies even under high current density conditions.