Title

Interaction of graphene, MnOx, and Ca2+ for enhanced biomimetic, ‘bubble-free’ oxygen evolution reaction at mild pH

Publication Name

International Journal of Hydrogen Energy

Abstract

Water electrolysis powered by renewable electricity will likely be critical to a future hydrogen economy. However, the typical use of strongly acidic or alkaline electrolytes necessitates the use of expensive materials, while bubbles add to capital and operational costs, due to blocking of the electrode surface and the necessary use of pumps and gas-liquid separators. Here ‘bubble-free’ oxygen evolution at mild pH is carried out using an electrocatalyst that mimics photosystem II (PSII). The bubble-free electrode includes a gas-extracting Gore-Tex® membrane. Edge-functionalised graphene (EFG) is included to mimic the metal-binding local protein environment, and the tyrosine residue, in the oxygen evolving complex (OEC) of PSII, while MnOx and Ca2+ are incorporated to mimic the Mn4CaO5 cluster. Interaction between EFG, MnOx, and Ca2+ results in a significant, 130 mV fall in the overpotential required to drive electrocatalytic oxygen evolution at 10 mA cm−2, compared to the electrode without these biomimetic components.

Open Access Status

This publication is not available as open access

Volume

46

Issue

56

First Page

28397

Last Page

28405

Funding Number

CE140100012

Funding Sponsor

Australian Research Council

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Link to publisher version (DOI)

http://dx.doi.org/10.1016/j.ijhydene.2021.06.094