Precisely Constructed Silver Active Sites in Gold Nanoclusters for Chemical Fixation of CO2

Abstract

Precise control of the composition and structure of active sites in an atom-by-atom fashion remains insuperable for heterogeneous catalysts. Here, we introduce tailor-made catalytic sites for the cycloaddition of CO₂ to epoxides achieved by implementing Ag atoms at different levels of liberation in atomically precise Au nanoclusters. Our results reveal that a single open Ag site on the Au₁₉ Ag₄ cluster improves the ring-opening of epoxides and sequent CO₂ insertion, while the partially exposed Ag site on the Au₂₀ Ag₁ cluster exhibits a weak affinity for epoxides and poor efficiency for CO₂ capture. Structural tunability imparted by the atom-by-atom tailoring and unusual atomic charges distributed on Au and Ag atoms of the three clusters seem to be crucial for promoting challenging bond cleavages and formations in the chemical utilization of CO₂ .

Keywords: CO2 fixation; active sites; gold; nanoclusters; silver.