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Abstract
The lack of availability of efficient, selective, and stable electrocatalysts is a major hindrance to the scalability of the CO2 reduction processes. The use of Cu with Indium (In) and Tin (Sn) to form bimetallic composite electrocatalyst materials has been shown, from our pioneering work, to greatly improve selectivity of CO2 reduction through changes in morphology and electronic structure. Such changes were a result of the suppression of the hydrogen evolution reaction (HER), whilst showing only a slight weakening of the adsorption energy of CO. Due to the mild poisoning of active sights through In incorporation however, Cu2O/In electrodes have previously demonstrated only mild current densities. By incorporating highly conductive Pt within the electrode back contact gas diffusion layer (GDL), we aim to develop upon prior electrocatalyst designs by overcoming this key limitation of electrode activity. Herein, we report a pioneering study into the dynamics of cutting-edge tri-metallic electrocatalysts, providing activity enhanced electrodes through Pt incorporation. Experimental results demonstrate how the incorporation of nano-thickness interfacial Pt layers within the catalyst bulk provides a facile method of activity control within a given range. Using a Pt-enriched GDE layer, current densities up to -204 mA cm−2 at -1.5 V vs RHE were observed, demonstrating a 183% improvement in electrocatalyst activity over that of Cu2O/In. Pt deposition within 2 μm of the electroactive surface additionally demonstrates highly consistent partial current densities for CO2 reduction products over a 24-hour period, suggesting Pt incorporation to provide minimal reduction in electrode stability with prolonged use. The study herein provides a cutting-edge method of enhancing electrocatalytic performance of previous Cu2O/In electrocatalyst designs through tailored, sub-surface Pt layer deposition.
