Mechanism of Water Dissociation with an Electric Field and a Graphene Oxide Catalyst in a Bipolar Membrane

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 H2O dissociation. In this Article, we performed a mechanistic and kinetic study of the H2O 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 H2O 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 H2O. Our findings provide avenues for improving the BPM efficiency to achieve higher energy and power densities for next-generation energy storages.