Decoupling Water Electrolysis with an Organic Pseudocapacitive Electrode

Abstract Utilizing a solid‐state redox electrode capable of reversibly storing proton‐electron pairs allows for decoupling water electrolysis, enabling separate hydrogen and oxygen production. This facilitates the conversion of renewable resources into hydrogen. However, the slow rate (<100 mA cm −2 ) of these electrodes for proton‐electron storage hinders practical application. Herein, a Dibenzo[b, i]phenazine‐5,7,12,14‐tetrone (DPT)‐based pseudocapacitive electrode to decouple acidic water electrolysis is introduced. Due to the fast kinetics, high capacity, and high stability of the DPT‐electrode for proton‐electron storage, the separated hydrogen and oxygen production exhibit a high rate of 800 mA cm −2 and a high cycle stability. When combined with a photovoltaic panel, this architecture enables the direct conversion of solar energy into pure hydrogen without using ion‐exchange membranes.