Mechanism of Water Dissociation with an Electric Field and a Graphene Oxide Catalyst in a Bipolar Membrane
Zhen Jiang, Peter P. Bazianos, Zhifei Yan, Andrew M. Rappe
Abstract
Bipolar membranes (BPMs) have recently been incorporated into energy storage devices to increase the overall battery potential and maintain a constant pH gradient by catalyzing internal H 2 O dissociation. In this Article, we performed a mechanistic and kinetic study of the H 2 O dissociation reaction on graphene oxide (GO) embedded in BPM using Car–Parrinello molecular dynamics (CPMD) and CPMD-based metadynamics methods. The synergistic effect of active sites (*OH, *C–O–C, and *C═C) on the GO catalyst and the electric field ( E ) strength across the GO catalyst were investigated for H 2 O splitting in a BPM. The results indicate the dominant activity of surface *OH sites, providing the lowest activation barrier (0.57 eV) among different sites on GO. Moreover, a higher E (>10 8 V/m) will significantly facilitate the dissociation reaction by polarizing the H–O bond in H 2 O. Our findings provide avenues for improving the BPM efficiency to achieve higher energy and power densities for next-generation energy storages.