# Pure Water Splitting Driven by Overlapping Electric Double Layers

## TL;DR

A new water splitting method uses overlapping electric layers to produce hydrogen efficiently without membranes or expensive materials.

## Contribution

A nanofluidic electrolyzer using overlapping electric double layers for pure water splitting without membranes or precious metals.

## Key findings

- The reactor achieves 2.8 A·cm–2 current density at 1.7 V using a nickel anode.
- Overlapping electric double layers enhance ion migration and water dissociation.
- The system avoids crossover of gases using convective flow between electrodes.

## Abstract

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. Convective
flow is introduced between the nanogap electrodes to suppress the
crossover of generated gases. The strong electric field within the
overlapping EDLs enhances ion migration and facilitates the dissociation
of water molecules. Acidic and basic environments, which are created in situ at the cathode and anode, respectively, enable the
use of nonprecious 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 toward a new type of
water electrolyzer that needs no membrane, no supporting electrolyte,
and no precious metal catalysts.