Importance of optimising electrodeposition parameters for scalable and cost-effective manufacturing of Cu catalysts for efficient electrochemical CO2 reduction to renewable fuels and chemical feedstocks

The electrodeposition of Cu-based catalysts onto commercial gas diffusion layers (GDLs) provides a scalable approach to the manufacturing of gas diffusion electrodes (GDEs) for efficient electrochemical CO₂ reduction into renewable fuels and chemicals. This study investigates the influence of electrodeposition parameters on the characteristics and performance of GDEs. The effect of different process parameters on the reproducibility of the GDEs was analysed, highlighting the importance of current density in overcoming nucleation issues that could cause uneven catalyst distribution. The relationship between current density, catalyst loading and GDE performance was then evaluated, revealing the necessity of balancing these parameters to achieve uniform catalyst distribution and prevent the formation of semi-continuous films that may block the surface of the GDL, negatively affecting the performance of the GDEs. By optimising both current density (30 mA cm⁻²) and catalyst loading (1 C cm⁻² or $\approx$ 0.33 mg cm⁻²), we prepared large GDEs (geometrical electrode active area of 5 cm${}^2$) that achieved up to 70% Faradaic efficiency for the conversion of CO₂ into useful products such as C₂H₄,

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under industrially relevant conditions (applied current density of 200 mA cm⁻² during CO₂ electrolysis) while saving 50% of catalyst material and 75% of electrodeposition time when compared to other GDEs prepared under different process parameters (e.g. 15 mA cm⁻² and 2 C cm⁻² or $\approx$ 0.66 mg cm⁻²). These results illustrate how important it is to adopt a strategic approach towards developing catalysts fabricated by electrodeposition, demonstrating how it is possible to significantly reduce their material and processing costs without compromising their performance.