Development of self-supported 3D microporous solder alloy electrodes for scalable CO2 electroreduction to formate

Abstract

Self-supported solder alloy electrodes having a three-dimensional (3D) microporous morphology have been investigated for the quantitative conversion of CO₂ into formate. The microporous morphologies have been achieved by electrochemical cathodization of the alloy electrodes at various potentials. The electrodes were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). Differential scanning calorimetry (DSC) results confirm the alloy nature of the electrodes, which retained their composition even after electrochemical cathodization. Investigation for CO₂ electroreduction and its conversion into formate was performed using cyclic voltammetry and chronoamperometry. The performance of the electrodes has been quantified in terms of faradaic efficiency (FE) and partial current density (PCD) for the conversion of CO₂ to formate. The overpotential for CO₂ electroreduction to formate has been found to be decreased for 3D microporous electrodes by 0.1 V as compared with flat electrodes. The best performance for the conversion was noted to be 88% FE and 4.8 mA cm⁻² PCD for the formate product at room temperature.