Proton‐Coupled Electron Transfer on Cu₂O/Ti₃C₂T_x MXene for Propane (C₃H₈) Synthesis from Electrochemical CO₂ Reduction

Electrochemical CO₂ reduction reaction (CO₂RR) to produce value-added multi-carbon chemicals has been an appealing approach to achieving environmentally friendly carbon neutrality in recent years. Despite extensive research focusing on the use of CO₂ to produce high-value chemicals like high-energy-density hydrocarbons, there have been few reports on the production of propane (C₃H₈), which requires carbon chain elongation and protonation. A rationally designed 0D/2D hybrid Cu₂O anchored-Ti₃C₂T_x MXene catalyst (Cu₂O/MXene) is demonstrated with efficient CO₂RR activity in an aqueous electrolyte to produce C₃H₈. As a result, a significantly high Faradaic efficiency (FE) of 3.3% is achieved for the synthesis of C₃H₈ via the CO₂RR with Cu₂O/MXene, which is ≈26 times higher than that of Cu/MXene prepared by the same hydrothermal process without NH₄OH solution. Based on in-situ attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and density functional theory (DFT) calculations, it is proposed that the significant electrocatalytic conversion originated from the synergistic behavior of the Cu₂O nanoparticles, which bound the *C₂ intermediates, and the MXene that bound the *CO coupling to the C₃ intermediate. The results disclose that the rationally designed MXene-based hybrid catalyst facilitates multi-carbon coupling as well as protonation, thereby manipulating the CO₂RR pathway.