Hydrogen Production from a Proton Exchange Membrane Photoelectrochemical Cell

J. Adams, D. Moser, B. Van Scoy, Dr. C. B. Clemons, Dr. D. Golovaty, Dr. K. Kreider, Dr. G. W. Young

A one-dimensional, non-isothermal model is developed to describe the proton distribution, electric potential, water content, and temperature profile throughout a proton exchange membrane photoelectrolysis cell (PEM PEC).  The anode catalyst layer, membrane, and cathode catalyst layer of the PEM- PEC are modeled while the effects of the water channels are accounted for in boundary conditions. The PEM membrane contains SO-3 charges which are modeled by delta functions. The total current density is composed of the current due to electrolysis and the photocurrent caused by sunlight due to the photoelectric effect. Numerical techniques are implemented to solve the coupled differential equations describing the system. Results include predictions of the amount of hydrogen production along with steady-state distributions of protons, electric potential, water content, and temperature throughout the cell. Data are compared for various sets of parameters to a default case. Hydrogen production for the default case is about 6 mL/min while values of up to 22 mL/min were obtained by increasing the size of the cell. Other variables studied include the number of SO−3 groups in the membrane, spacing of the charge groups, and sizes of the regions along with the effects of photocurrent, mobility, and temperature on hydrogen production.