CuCo₂O₄ as Catalyst for Oxygen Evolution Reaction in Anion Exchange Membrane Water Electrolysis

Abstract
The UK government aims to achieve net-zero greenhouse gas emissions by 2050 [1]. Water electrolysers (WEs) represent a promising solution for generating high-purity hydrogen fuel without environmental pollution. Among WE technologies, Anion Exchange Membrane Water Electrolysers (AEMWEs) offer a unique combination of the benefits of alkaline water electrolysers (AWEs) and proton exchange membrane water electrolysers (PEMWEs). However, the performance of AEMWEs heavily depends on precious metal catalysts for the oxygen evolution reaction (OER), making them cost-prohibitive. This study investigates Copper Cobalt Oxide (CCO) spinels as a low-cost, high-performance alternative to precious metal catalysts.

Methods
A hydrothermal synthesis approach, adapted from Abu Talha Aqueel Ahmed et al. [2], was used to synthesise CCO spinels. Reaction parameters, including precursor ratios, temperatures, and synthesis durations, were systematically varied to optimise catalyst composition and morphology. Synthesised materials were characterised using SEM/EDX and XRD to confirm structure and composition.

Results
Physical characterisation revealed the successful synthesis of CCO nanoparticles with distinct morphologies, including flower-like and needle-like structures. Increasing the hydrothermal synthesis temperature to 180°C enhanced purity and homogeneity. Electrochemical testing via cyclic voltammetry (CV) demonstrated that incorporating Cu into the CCO structure improved OER activity, reducing the onset potential and increasing the current density.

Conclusions
This study highlights the potential of CCO spinels as cost-effective, efficient OER catalysts for AEMWEs. The optimised hydrothermal synthesis protocol and resulting nanostructures significantly improved catalytic activity, paving the way for sustainable hydrogen production technologies.

References

[1] UK Hydrogen Strategy, S.o.S.f.B.E.a.I. Strategy, Editor. 2021.

[2] Aqueel Ahmed, Abu Talha, Sambhaji M. Pawar, Akbar I. Inamdar, Hyungsang Kim, and Hyunsik Im. "A morphologically engineered robust bifunctional CuCo2O4 nanosheet catalyst for highly efficient overall water splitting." Advanced Materials Interfaces 7, no. 2 (2020): 1901515