Unexpectedly Spontaneous Water Dissociation on Graphene Oxide Supported by Copper Substrate

TL;DR

This study reveals that copper-supported graphene oxide can spontaneously dissociate water molecules due to substrate-induced orbital interactions, significantly lowering the activation barrier and enhancing catalytic activity.

Contribution

It introduces a novel substrate-assisted mechanism for water dissociation on graphene oxide, demonstrating how copper substrate enhances interfacial oxygen activity via orbital hybridization.

Findings

Water dissociation on Copper-GO occurs spontaneously with low activation barrier.

Orbital hybridization between copper and GO enhances interfacial oxygen reactivity.

Substrate plays a crucial role in tuning catalytic performance of 2D materials.

Abstract

Water dissociation is of fundamental importance in scientific fields and has drawn considerable interest in diverse technological applications. However, the high activation barrier of breaking the O-H bond within the water molecule has been identified as the bottleneck, even for the water adsorbed on the graphene oxide (GO). Herein, using the density functional theory calculations, we demonstrate that the water molecule can be spontaneously dissociated on GO supported by the (111) surface of the copper substrate (Copper-GO). This process involves a proton transferring from water to the interfacial oxygen group, and a hydroxide covalently bonding to GO. Compared to that on GO, the water dissociation barrier on Copper-GO is significantly decreased to be less than or comparable to thermal fluctuations. This is ascribed to the orbital-hybridizing interaction between copper substrate and GO, which enhances the reaction activity of interfacial oxygen groups along the basal plane of GO for water dissociation. Our work provides a novel strategy to access water dissociation via the substrate-enhanced reaction activity of interfacial oxygen groups on GO and indicates that the substrate can serve as an essential key to tuning the catalytic performance of various two-dimensional material devices.