Enhanced CO₂ Electroreduction to Ethylene on Laser-Synthesized Copper Phyllosilicate Catalysts

Carbon dioxide electrochemical reduction (CO2 ECR) to ethylene is a promising means of simultaneously mitigating CO2 emissions and producing an important feedstock for industrial, environmental, and agricultural sectors without petroleum. However, developing CO2 ECR catalysts with high ethylene selectivity remains a challenge. This work reports the synthesis of copper phyllosilicate (CuPS) CO2 ECR catalysts using the nonequilibrium reactive laser ablation in liquid (RLAL) technique. Compared to CuPS synthesized through conventional ammonia evaporation (CuPS-AE), which only contained Cu2+ species, the RLAL-synthesized CuPS catalysts had higher Cu loading and contained reduced copper (Cu+). Cu-PS synthesized using 30 fs laser pulses (CuPS-fs) contained nearly 50% more Cu+ than CuPS synthesized using 4 ps pulses (CuPS-ps), along with a higher concentration of crystalline Cu2O phases within the amorphous CuPS network. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements showed a higher fraction of CO2 adsorption on copper sites as compared to oxygen functional group sites for the CuPS-fs catalyst. CO2 ECR measurements showed exceptional ethylene selectivity for the CuPS-fs catalyst, reaching 84% Faradaic efficiency (FE) at −1.1 V vs RHE, compared to 29 and 16% for the CuPS-ps and CuPS-AE catalysts, respectively. Moreover, the CuPS-fs catalyst exhibited exceptional stability, maintaining more than 80% FE to ethylene and 10 mA cm–2 current density over 30 h on stream.