Microwave-Assisted Fabrication of Copper Oxide/N-Doped Carbon Nanocatalyst for Efficient Electrochemical CO₂ Conversion to Liquid Fuels

Electrochemical CO₂ reduction reaction (CO₂RR), which is driven by electricity generated from renewable energy sources, is a promising technology for sustainably producing carbon-based chemicals or fuels. Several CO₂RR catalysts have been explored to date, among which copper-based electrocatalysts are the most widely known for electrochemical CO₂RR and are extensively studied for their ability to generate an array of products. Their low selectivity, however, hinders their possibility of being used for practical purposes. In this work, a microwave-assisted one-pot synthesized Cu_xO/N-doped carbon demonstrates the electrochemical conversion of carbon dioxide into multiple C₁ products (mainly formate and methanol), with a maximum Faradaic efficiency of 95% in 0.10 m KHCO₃ aqueous solution at a moderately low applied potential of -0.55 V versus RHE (reversible hydrogen electrode). The in-depth theoretical study reveals the key contribution of pyridinic N-based N-doped carbon sites and Cu₂O clusters in CO₂ adsorption and its subsequent conversion to formate and methanol via an energetically favorable formate pathway. The electrocatalyst continued to demonstrate CO₂ reduction to valuable C₁ products when a simulated flue gas stream containing 15% CO₂ along with 500 ppm SO_x and 200 ppm NO_x is used as an inlet feed.