Ordered proton channels constructed from deoxyribonucleic acid-functionalized graphene oxide for proton exchange membranes via electrostatic layer-by-layer deposition

Abstract

Based on the construction strategy of proton transport channels, we design a high-performance proton exchange membrane (PEM) with ordered deoxyribonucleic acid (DNA)-functionalized graphene oxide (GO) and Nafion matrix via the electrostatic layer-by-layer deposition (ELD) technique, which is a novel method of membrane formation aided by electrostatic force. The effects of different content rations of single-strand DNA (ss-DNA) molecules and GO (ss-DNA@GO) on the proton conductivity, methanol permeability, and single cell performance of composite PEMs are investigated. The composite membrane shows a high proton conductivity of 351.8 mS cm−1 (80 °C, 100%RH) but a low methanol permeability of 1.63 × 10−7 cm2 s−1 at room temperature. Furthermore, the composite membranes are assembled into direct methanol fuel cells at 60 °C, and Nafion/DNA@GO-2/5 exhibits a maximum power density of 255.33 mW cm−2, which is 2.42 times higher than that of pure Nafion. This work explores the application potential of DNA@GO in PEM and provides a bioinspired avenue to designing next-generation high-performance PEM for fuel cells.