Synthesis of bimetallic catalysts using Ag extracted from end-of-life solar modules supported on nanoporous Cu for electrochemical CO2 reduction

Photovoltaics and carbon dioxide reduction reaction (CO2RR) products are both promising renewable energy sources for conserving the environment. However, the re-utilization of accumulated solar module waste and the development of effective catalysts remain challenging in related industries. In this study, nanoporous Cu (NPC) film with an average ligament size of 30 ± 6 nm was used as a substrate for extracting Ag from end-of-life solar module waste to synthesize a bimetallic catalyst for CO2RR. The results showed that the galvanic replacement reaction produced a dendrite-like Ag morphology, whereas pulse electrodeposition produced two-dimensional Ag precipitates with a plate-like shape. The Faraday efficiency (FE) values for CO, HCOOH, and C2H4, which were the conversion products obtained from CO2RR with this catalyst, were 13%, 29%, and 2%, respectively. The FE ratio for CO relative to that for HCOOH could be adjusted from 0.45 to 3.5 by controlling the amount of Ag deposited, or by using either Cu foil or NPC as the substrate. These results may be explained by the high surface area presented by the nanoporous material, which allowed the NPC structure beneath the deposited Ag to retain its catalytic performance. •Ag extracted from end-of-life solar module waste and deposited on Cu by hydrometallurgical methods.•C2H4, CO, and HCOOH converted by CO2 reduction reaction using bimetallic Cu–Ag as catalysts.•Rate of CO2 reduction reaction with nanoporous Cu as catalyst three times higher than that with Cu foil.•Selectivity of products could be adjusted by varying amount of Ag deposited or Cu substrate.