Visualization of oxygen bubble behavior depending on porous material in PEM water electrolysis cell

抄録

In recent years, water electrolysis technology that converts renewable energy into hydrogen has attracted attention to build a hydrogen energy system. Improving efficiency is essential for the future commercialization of proton exchange membrane (PEM) water electrolysis. One of the serious problems is that the staying of generated oxygen bubbles on the reaction site inhibits the water supply and significantly reduces the reaction efficiency. However, the mechanism of generation, growth, and detachment of oxygen bubbles in PEM water electrolysis cells has not been clarified. Therefore, it is necessary to understand these behaviors. In this study, the bubble behavior was observed on two types of anode porous transport layer (PTL) with non-treated and hydrophobic surface by using a high-speed camera. The oxygen bubble detachment speed was faster with a non-treated anode PTL than with a hydrophobic anode PTL. Moreover, a hydrophobic anode PTL hold more bubbles on the surface of PTL than a non-treated anode PTL. Therefore, it was assumed that the oxygen bubble behavior depend on the hydrophobicity of the anode PTL.