Surface Functionalization of Industrial Materials and its Influence on Oxygen Nucleation

Proton-exchange membrane (PEM) electrolysis is one of the mostly used principles for H2 generation. To increase its efficiency, an enhanced O2 separation in the anodic cycle is necessary to reduce overvoltage and improve cooling. In this work, we investigate the surface functionalization with direct laser interference pattering (DLIP) and plasma coating (PECVD) of Ti64 and polypropylene to tune the affinity of the nonpolar gas to the materials by varying the hydrophilicity/hydrophobicity. The water contact angle is used to characterize the wettability. It gradually increases after the DLIP due to the adsorption of carbon compounds from the environment [1]. We observed that the effect is highly dependent on the surrounding media and also is reversible. Our experimental findings are supported by XPS and confocal microscopy measurements. Since DLIP requires heat resistant materials, we further investigated low-pressure plasma coating. Via optical recording we analyse the influence of the wettability on the O2 nucleation and provide first insights on how the oxygen separation of the anodic cycle of PEM electrolysers can be tuned by surface functionalization.