Recycling spent batteries to green innovation: a CuCo-based composite as an electrocatalyst for CO2 reduction†

Abstract

The reuse of solid and gaseous waste is necessary to achieve a significant advance toward more sustainable and eco-friendly processes. It is a challenge in the electronic industry, where the materials are generally expensive and toxic (if disposed of in nature), requiring strategies for maximum material recovery. Here, we report a strategy to recycle lithium-ion batteries (LIBs), preparing a copper–cobalt composite catalyst designed to operate in electrochemical CO₂ reduction to hydrocarbons. The proposed method allows fast and easy electrodeposition of a thin layer of spherical Cu/Co nanoparticles over a conductive substrate. The electrodes were assessed for their CO₂ reduction activity at different potentials (−0.13, −0.33, and −0.53 V vs. RHE). As a result, we achieved different products such as methanol, acetic acid, ethanol, and hydrogen with selectivity according to the applied potential. The highest production and faradaic efficiency for C₁₊ compounds were for methanol, reaching 103 μmol mg_cat and 65% after 3 h of reaction at an applied potential of −0.13 V vs. RHE. A proposed scheme, based on in situ FTIR spectra using D₂O, suggests that CO₂ initially undergoes one-electron reduction, forming *CO_ads, which acts as a stable intermediate on the Cu surface. The Cu surface predominantly drives the reaction despite its higher amount in the CuCo-based composites. From that, various pathways can arise from the protonation of the intermediate, leading to the production of C₂₊ alcohols in smaller quantities or C₁ alcohols in larger quantities and intensity.