Ultrafine Cu-Pd bimetallic clusters enhance asymmetric electron distribution to boost C-C coupling in photothermal CO2-to-ethanol conversion

Abstract

Converting CO2 to ethanol through photothermal catalysis faces significant challenges due to it involves multi-electron reduction and kinetically sluggish C-C coupling process. Here, copper and a minor quantity of palladium are encapsulated within the cage of UiO-66 using a dual-solvent-sonication method to form ultrafine Cu2O/Cu-Pd clusters. The Cu-Cu2O serves as an electron center to enhance CO2 uptake and activation, while the incorporation of Pd accelerates H2 activation. Due to differences in electronegativity, electrons tend to transfer from Cu to Pd, which reduces the electrostatic repulsion between intermediates and facilitates the coupling of *CO and *CHO. The photothermal ethanol yield of Cu6Pd@UiO-66 reached 1077.69 μmol·gcat–1·mL–1 with a selectivity of 94.62%, representing an 11.64-fold increase over the non-illumination, and a 3.11-fold enhancement compared with Cu6@UiO-66. This study offers evidence supporting the promotion of C-C coupling through an asymmetric electron distribution, potentially advancing the conversion of CO2 to liquid products.