MWCNT-supported Cu11In9 nanoparticles for CO2 electroreduction to CO

Developing efficient and low-cost electrocatalysts is important for sustainable CO 2 utilization. Here, spherical Cu 11 In 9 alloy nanoparticles were synthesized on an MWCNT network via an impregnation-assisted reduction method. Electrochemical measurements in an H-type cell showed that Cu 11 In 9 @MWCNTs promoted CO 2 -to-CO conversion in 0.3 mol L −1 tetrabutylammonium chloride/acetonitrile (Bu 4 NCl/AN) electrolyte. At −2.4 V vs SHE, the Faradaic efficiency for CO (FE CO ) reached 95.8%, and the CO partial current density ( j CO ) approached 40 mA cm −2 . During 20 h of continuous electrolysis, the catalyst maintained approximately 95% CO selectivity and a stable current density. XPS and PDOS analyses indicated that Cu-In alloying modified the local electronic structures of Cu and In and shifted the d-band center of Cu away from the Fermi level. DFT calculations further showed more favorable CO 2 -to-CO energetics and less favorable H adsorption on Cu 11 In 9 than on Cu and In, consistent with the experimentally observed high CO selectivity and low H 2 formation. The MWCNT network maintained the dispersion and structural stability of the alloy nanoparticles, thereby increasing the exposure of accessible active sites and facilitating electrolyte contact and charge transport.