Carbon Dioxide to Methane using Ruthenium Nanoparticles: Effect of the Ionic Liquid Media

Abstract

Carbon dioxide hydrogenation to methane is efficiently achieved using ruthenium nanoparticles (Ru NPs) prepared and stabilized in task-specific ionic liquids. 1-Octyl-3-methylimidazolim perfluorobutanesulfonate [C8mim][NfO] is the best ionic liquid media producing 84% yield of methane at 150 °C. Other fluorinated anions based ionic liquids exhibited a greater influence on the methane production. In parallel, carbon monoxide is selectively produced in a small amount for the ionic liquid media containing trifluoroacetate and mesylate anions. It is known that ionic liquids strongly contribute to higher CO2 solubility as well as the formation and stabilization of Ru NPs. The catalytic system maintains some activity at least after 5 recycling studies and a promissory improvement can be achieved using a further continuous-flow system.