Development of a new solar photoelectrochemical reactor design for more efficient hydrogen production

Abstract

This study concerns a new photoelectrochemical reactor design for hydrogen production to avoid the bubble formation on the surface of the electrode through the hydrogen production process via photoelectrochemical techniques. The proposed design contains two dome electrodes (photocathode and anode) immersed in the electrolyte in two cylindrical chambers. These novel electrode configurations are designed to increase the active area of the electrodes to receive the maximum possible amount of sunlight energy over the day due to the dome shape and consequently to increase the production rate of hydrogen and enhance the conversion efficiency of solar to hydrogen. The reactor is made of a good absorptivity cylindrical acrylic glass to transfer maximum wavelengths. In this study, the governing equations of the new proposed photoelectrochemical cell, particularly for fluid flow and heat transfer are modeled and solved. Moreover, the electrochemical simulation of the photoelectrochemical reactor is performed and analyzed using the Engineering Equation Solver with its built-in thermodynamic database. The effects of the solar incident flux, illuminated photoelectrode area, and quantum efficiency on the solar to hydrogen efficiency and hydrogen production rate are further investigated. According to the modeling results, the solar to hydrogen and electrolysis efficiencies are 6.10% and 30.51%, respectively, at a hydrogen mass flow rate of 75.82 μg/s occurring at the illuminated area of 0.084 m2 and solar flux of 600 W/m2. An extensive parametric study is performed to determine the significant results of the developed photoelectrochemical cell. Moreover, the maximum hydrogen production rate that could be obtained is 131.6 μg/s at an electrode illuminated area of 0.14 m2. The highest energy efficiency of solar to hydrogen is obtained as 8.98% at 400 W/m2 of solar irradiance.