Giant photo-effect in proton transport through graphene membranes

TL;DR

This paper demonstrates a significant enhancement of proton transport through graphene membranes when illuminated with visible light, revealing a photoresponsivity comparable to advanced photodetectors and opening new avenues for energy and separation technologies.

Contribution

It uncovers a giant photo-effect in proton transport through graphene, showing light can dramatically increase proton permeation, a novel finding in 2D material-based membranes.

Findings

Proton transport is strongly enhanced by visible light illumination.

Achieved a photoresponsivity of 10^4 A W-1 and a gain of 10^4 protons per photon.

Response times are in the microsecond range, suitable for practical applications.

Abstract

Graphene has recently been shown to be permeable to thermal protons, the nuclei of hydrogen atoms, which sparked interest in its use as a proton-conducting membrane in relevant technologies. However, the influence of light on proton permeation remains unknown. Here we report that proton transport through Pt-nanoparticle-decorated graphene can be enhanced strongly by illuminating it with visible light. Using electrical measurements and mass spectrometry, we find a photoresponsivity of 10^4 A W-1, which translates into a gain of 10^4 protons per photon with response times in the microsecond range. These characteristics are competitive with those of state-of-the-art photodetectors that are based on electron transport using silicon and novel two-dimensional materials. The photo-proton effect can be important for graphene's envisaged use in fuel cells and hydrogen isotope separation. Our observations can also be of interest for other applications such as light-induced water splitting, photocatalysis and novel photodetectors.