Amino Modified Carbon Dots with Electron Sink Effect Increase Interface Charge Transfer Rate of Cu-Based Electrocatalyst to Enhance the CO2 Conversion Selectivity to C2H4

Electrocatalytic conversion of CO2 to valuable products, especially for ethylene (C2H4), is an urgent challenge in material science and catalysis. Cu-based materials are the most promising catalysts to realize C-2 products from CO2 reduction, while, they often suffer from the poor selectivity and efficiency. Here, it is shown that -NH2-modified carbon dots (NCDs) can regulate the electron transfer behavior on Cu/CuO catalyst, and then enhance the CO2 conversion selectivity to C2H4. The selectivity of C2H4 (in carbon products) on NCDs/Cu/CuO composites is increased by 1.2 times when compared with that of Cu/CuO catalysts. NCDs increase the adsorption capacity of catalysts to CO2 by 18.2%. Transient photo-induced voltage (TPV) tests are used to reveal the effect of NCDs on electron transfer behavior at the catalyst interface. On one hand, NCDs reduce the electron transfer resistance between Cu/CuO particles, increasing the overall electron transfer rate by 37%; on the other hand, NCDs with electron sink effect can increase the electron concentration on catalyst surface significantly. These effects significantly promote the C-C coupling reactions over NCDs/Cu/CuO composite catalysts. This work provides a new understanding and approach to address the challenges of improving electrocatalytic reduction of CO2 to multi-carbon products.