Heterogeneous Catalytic Generation of Hydrogen from Formic Acid under Pressurized Aqueous Conditions

Abstract

PtRuBiOx/C catalyst has shown the promise for catalyzing CO-free hydrogen generation from formic acid in aqueous solution at room temperature and atmospheric pressure. In order to produce hydrogen at moderate-pressure to feed into a fuel cell stack, postgeneration compression is needed to overcome the flow resistance. In the present study, liquid formic acid decomposition over the PtRuBiOx/C catalyst was investigated at temperatures ranging from 80 to 140 °C and pressure up to 350 psi. It was found that the selectivity of the catalyst for formic acid decomposition remained almost 100%, and a complete conversion of formic acid could be achieved in several hours, which is significantly shorter than that at ambient conditions. The overall activation energy was also found to be 78 kJ·mol–1 under present conditions. The increase from the previously determined value of 37 kJ/mol at open atmosphere pressure was due to carbon dioxide release beyond saturation at elevated pressures. Furthermore, the stability of the catalyst was confirmed by performing a series of repeated runs.