Pure Water Splitting Driven by Overlapping Electric Double Layers

In pursuit of a sustainable future powered by renewable energy, hydrogen production through water splitting should achieve high energy efficiency with economical materials. Here, we present a nanofluidic electrolyzer that leverages overlapping cathode and anode electric double layers (EDLs) to drive the splitting of pure water. The strong electric field within the overlapping EDLs enhances ion migration and facilitates the dissociation of water molecules. Acidic and basic environments, that are created in situ at cathode and anode, respectively, enable the use of non-precious metal catalysts. All these merits allow the reactor to exhibit a current density of 2.8 A·cm-2 at 1.7 V with a nickel anode. This paves the way towards a new type of water electrolyzers without membranes, supporting electrolytes, or precious metal catalysts.