Nafion fluorine-modified rGO-modified Cu electrode for efficient electrocatalytic CO2 reduction

Abstract

Oxide-derived Cu catalysts with multiple chemical states have been shown to promote C-C coupling in electrochemical reduction of CO₂ (CO₂RR) for forming valuable multi-carbon product, but their scalability has been strongly limited by using complex templates or reducing agents. In this work, we propose a simple yet highly controllable synthetic strategy to construct the Nafion fluorine-modified reduced graphene oxide (rGO-Nafion) modified Cu electrodes, which shows good activity for the production of C₂ products in CO₂RR. XRD and XPS analyses reveal that the introduction of rGO-Nafion stabilizes the Cu/CuO heterostructure and promotes the partial conversion of Cu²⁺ into Cu⁺/Cu⁰, in which metallic Cu, Cu⁺ species, and rGO-Nafion act cooperatively to optimize intermediate adsorption and suppress competing hydrogen evolution, finally leading to significantly improved CO₂RR activity and product selectivity. The optimized rGO-Nafion-Cu-60 + 60 µL electrode thus achieves a stable current density of approximately − 20 mA cm^− 2 at − 1.0 V vs. RHE, delivering a high C₂ (C₂H₄, C₂H₆, and C₂H₅OH) Faradaic efficiency of 39% and a total carbon-based Faradaic efficiency (CO, formate, and C₂ products) of 72%.