Waste-Derived Copper-Lead Electrocatalysts for CO Reduction.

It remains a real challenge to control the selectivity of the electrocatalytic CO reduction (eCOR) reaction to valuable chemicals and fuels. Most of the electrocatalysts are made of non-renewable metal resources, which hampers their large-scale implementation. Here, we report the preparation of bimetallic copper-lead (CuPb) electrocatalysts from industrial metallurgical waste. The metal ions were extracted from the metallurgical waste through simple chemical treatment with ammonium chloride, and CuPb electrocatalysts with tunable compositions were fabricated through electrodeposition at varying cathodic potentials. X-ray spectroscopy techniques showed that the pristine electrocatalysts consist of Cu, Cu and Pb domains, and no evidence for alloy formation was found. We found a volcano-shape relationship between eCOR selectivity toward two electron products, such as CO, and the elemental ratio of Cu and Pb. A maximum Faradaic efficiency towards CO was found for CuPb, which was four times higher than that of pure Cu, under the same electrocatalytic conditions. Raman spectroscopy revealed that the optimal amount of Pb effectively improved the reducibility of the pristine Cu and Pb domains to metallic Cu and Pb, which boosted the selectivity towards CO by synergistic effects. This work provides a framework of thinking to design and tune the selectivity of bimetallic electrocatalysts for CO reduction through valorization of metallurgical waste.