Floating Membraneless PV-Electrolyzer Based on Buoyancy-Driven Product Separation

Although the sun is a promising energy source to meet society’s demands, the storage of solar energy during intermittent hours remains a significant challenge. One possible solution is to electrolyze water into hydrogen fuel. The ocean is an untapped source of abundant water and space, but modern proton exchange membrane electrolysis devices are ill-equipped to electrolyze seawater due to their intolerance to the impurities present in the ocean. Motivated by this challenge, our group has recently investigated the application of membraneless electrolyzers based on mesh flow-through electrodes for seawater electrolysis. In this study, we have demonstrated a stand-alone, floating PV electrolyzer capable of safe and reliable separation of H₂ and O₂ product gases via bubble buoyancy in the absence of forced convection. By selectively depositing the electrocatalyst on only one side of mesh flow-through electrodes, we were able to separate the product gases with high purity in an un-pumped, free-standing electrolyte. This electrode architecture was applied to a 3D printed floating laboratory-scale PV-electrolyzer that achieved a solar-to-hydrogen efficiency of ~5%.[1]

[1] Davis, et al. 2017 Floating Membraneless PV-Electrolyzer Based on Buoyancy-Driven Product Separation Manuscript in Submission.