An atmospheric water electrolyzer for decentralized green hydrogen production

• Published in: Cell reports physical science 2021-11, Vol.2 (11), p.100627, Article 100627
• Main Authors: Thimmappa, Ravikumar, Gautam, Manu, Bhat, Zahid M., Thodika, Abdul Raafik Arattu, Devendrachari, Mruthunjayachari C., Mukhopadhyay, Sanchayita, Dargily, Neethu Christudas, Thotiyl, Musthafa Ottakam
• Format: Article
• Language: English
• Subjects: atmospheric water electrolyzer; graphene oxide membrane; proton conductivity; proton exchange membrane
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2021.100627

The necessity of ultrapure water and water-transport infrastructure pose grand challenges in renewable-energy-assisted water electrolysis to produce green hydrogen. Directly accessing atmospheric water should offer a decisive solution because it provides ∼13 trillion kiloliters of pure water at any given instant. We show that the central challenge for atmospheric water electrolysis is related to the water-sorption kinetics of the proton-conducting membrane where state-of-the-art membranes critically fail. A proof-of-concept atmospheric water electrolyzer is demonstrated with a graphene oxide proton-conducting membrane, which has nearly three times higher water-sorption kinetics and ten times higher hydration number than a Nafion membrane due to capillary water condensation and the abundant presence of hydrophilic functionalities. At a wind velocity of ∼50 km/h, this electrolyzer delivers nearly 18 mL/h/cm2 of green hydrogen directly from the feedstock of atmospheric water. Because this electrolyzer does not require water-transport infrastructure, it can be placed almost anywhere, which offers opportunities for decentralized green hydrogen production. [Display omitted] Direct harvesting of atmospheric water to produce green hydrogenWater-sorption kinetics of the membrane is crucial for atmospheric water electrolysisVery high water-sorption kinetics of graphene oxide aids atmospheric water electrolysis Thimmappa et al. report a renewable-energy-driven, graphene-based atmospheric water electrolyzer. In theory, this can be placed almost anywhere because it does not require ultrapure water supply and water-transport infrastructure, offering a feasible approach toward decentralized green hydrogen production.