Theoretical Insights into Enhancing Catalytic Performance of Al-Cu Alloy for CO 2 Electroreduction toward Ethene Production.

The understanding of the reaction mechanism of CO 2 electroreduction (CO 2 RR) is essential for the precise design of catalysts for specific products with high selectivity. In this work, combined with the computational hydrogen electrode model and kinetic energy barrier calculations, CO 2 RR pathways on Cu(100) and Al 1 Cu 3 (100) are intensively investigated. The free energy barrier of the rate-determining step of ethylene formation is reduced from 1.08 eV for *CCOH formation on Cu(100) to 0.51 eV for *CH 2 OCHOH formation on Al 1 Cu 3 (100) and enhances the catalytic activity. The reaction free energy of *CO-*CO coupling is remarkably reduced from 0.86 eV on Cu(100) to -0.43 eV on Al 1 Cu 3 (100) and the coupling barrier is reduced from 0.97 to 0.37 eV, suppressing the production of gas phase CO and enhancing the production of C 2 products. Furthermore, the selectivity toward C-O breaking of *CH 2 CHOH on Cu(100) and *CH 2 CH 2 OH on Al 1 Cu 3 (100) ensures high selectivity toward ethene rather than ethanol.