Heterogeneous Catalytic Reactor for Hydrogen Production from Formic Acid and Its Use in Polymer Electrolyte Fuel Cells

A proof-of-concept prototype of a medium-scale heterogeneous catalytic reactor for continuous production of hydrogen through formic acid (FA) dehydrogenation has been developed. A commercial proton exchange membrane (PEM) fuel cell (FC) fed with the resulting gas outflow (H2 + CO2) was applied to convert chemical energy to electricity. To implement an efficient coupling of the reactor and FC, research efforts in three interrelated areas were undertaken: 1) catalyst development and testing; 2) computer modelling of heat and mass transfer to optimize the reactor design and 3) study of compatibility of the reactor gas outflow with a PEM FC. During the catalyst development, immobilization of a homogeneous Ru – metatrisulphonated triphenylphosphine (mTPPTS) catalyst on different supports was performed and Ru-mTPPTS supported on phosphinated polystyrene beads demonstrated the best results. A validated mathematical model of the catalytic reactor with coupled heat transfer, fluid flow and chemical reactions was proposed for catalyst bed and reactor design. Measured reactor operating characteristics were used to refine modelling parameters. In turn, catalyst bed and reactor geometry was optimised during an iterative adaptation of the reactor and model parameters. In the final phase, PEM FC operating conditions and (H2+CO2) gas treatment were optimized to provide the best FC efficiency and lifetime. Stable performance of a commercial 100W PEM FC coupled with the developed reactor prototype was successfully demonstrated. The low CO concentration (below 5 ppm) in the reformate was insured by preferential oxidation (PROX).