Proton-Coupled Electron Transfer on Cu 2 O/Ti 3 C 2 T x MXene for Propane (C 3 H 8 ) Synthesis from Electrochemical CO 2 Reduction.

Electrochemical CO 2 reduction reaction (CO 2 RR) 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 CO 2 to produce high-value chemicals like high-energy-density hydrocarbons, there have been few reports on the production of propane (C 3 H 8 ), which requires carbon chain elongation and protonation. A rationally designed 0D/2D hybrid Cu 2 O anchored-Ti 3 C 2 T x MXene catalyst (Cu 2 O/MXene) is demonstrated with efficient CO 2 RR activity in an aqueous electrolyte to produce C 3 H 8 . As a result, a significantly high Faradaic efficiency (FE) of 3.3% is achieved for the synthesis of C 3 H 8 via the CO 2 RR with Cu 2 O/MXene, which is ≈26 times higher than that of Cu/MXene prepared by the same hydrothermal process without NH 4 OH 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 Cu 2 O nanoparticles, which bound the *C 2 intermediates, and the MXene that bound the *CO coupling to the C 3 intermediate. The results disclose that the rationally designed MXene-based hybrid catalyst facilitates multi-carbon coupling as well as protonation, thereby manipulating the CO 2 RR pathway.