High-Pressure Electrochemical Hydrogen Purification Process Using a High-Temperature Polybenzimidazole (PBI) Membrane

A high-pressure electrochemical hydrogen purification system comprising a two-chamber electrochemical cell and fully automatic flow, pressure, and temperature control units has been successfully constructed. The electrochemical hydrogen purification process using a high-temperature polybenzimidazole membrane and Pt electrocatalysts has been investigated via polarization measurements and product analysis at elevated pressure. Measured linear potential-current curves demonstrate high electrode polarizations in simulated reformate gas containing hydrogen, carbon monoxide, and carbon dioxide. The adsorption of both CO and CO2 onto Pt electrocatalysts at increased pressure has been proposed to be responsible for the high electrode polarizations. The gas chromatography analysis of cathode products suggests that high-purity hydrogen could be obtained at the cathode side, albeit with a small amount of CO2 as impurity. Further research on the optimization of the high-pressure electrochemical purification process for minimized electrode polarizations and maximized hydrogen purity is under way at the Energy and Environmental Research Center.