Anodic Conversion of Cyclohexane, Methylcyclohexane, and 2-Propanol: Towards a Regenerable Liquid-Fed Fuel Cell

Abstract Liquid Organic Hydrogen Carriers (LOHCs) are promising for hydrogen and energy storage but require endothermic catalytic dehydrogenation. An alternative approach is a regenerable liquid-fed fuel cell which spontaneously converts an organic carrier from its hydrogen-rich to hydrogen-lean form while generating electrical power. The anodic electrooxidation of cyclohexane, methylcyclohexane and 2-propanol in a high temperature polybenzimidazole/phosphoric acid (PBI/PA) PEM fuel cell was investigated along with a quantitative analysis of reaction products. Cyclohexane and methylcyclohexane were predominantly converted to CO2 with only a trace formation of the corresponding aromatic and cyclic olefin byproducts. This near-to-complete oxidation of the fuels is in sharp contrast to previous reports of a selective conversion of cyclohexane to benzene, with no CO2 byproducts. In experiments with 2-propanol, acetone was produced, with diisopropyl ether, propylene and CO2 as only minor side products. However, the extent of CO2 formation greatly increased at higher current densities.