Monopalladium Substitution in Gold Nanoclusters Enhances CO₂ Electroreduction Activity and Selectivity

Abstract

Atomically precise gold nanoclusters provide opportunities for correlating the structure and electrocatalytic properties at the atomic level. Here, we report the single-atom doping effect on CO2 reduction by comparing monopalladium-doped Pd1Au24 and homogold Au25 nanoclusters (both protected by thiolates) that share an identical core structure. Experimental results show that single Pd-substitution drastically inhibits H2 evolution at large currents; thus, Pd1Au24 can convert CO2 to CO with ∼100% faradaic efficiency ranging from −0.6 (onset) to −1.2 V (vs RHE), while Au25 starts to decline at −0.9 V. Theoretical simulations reveal that the Pd dopant influences the Au nanocluster properties through a unique mechanism different from that in conventional alloy nanoparticles. The surface S atoms of the thiolate ligand are identified as the active sites (with the Au13 core as the electron reservoir) for selective CO2 reduction, whereas undercoordinated Au atom active sites are predicted to favor H2 evolution. Thermodynamic analysis of the ligand removal process predicts that Pd1Au24 should retain a larger population of S atom active sites under cathodic potentials compared with Au25, which extends the potential range for selective CO2 reduction. Our results demonstrate that single-atom substitution can substantially improve the CO2 reduction selectivity of gold nanoclusters at large potentials. The dopant-induced ligand stability may serve as a design strategy to modify the stability of catalytic active sites under harsh conditions.

Homoleptic Alkynyl‐Protected Ag15 Nanocluster with Atomic Precision: Structural Analysis and Electrocatalytic Performance toward CO2 Reduction

“…Figure 1cpresents the simulated absorbance spectrum of [Ag 15 (CCÀCH 3 ) 12 ] + along with the experimental one.T osimplify the calculation, all C C-t Bu ligands are replaced with C C À CH 3 ,w hich has been regarded as ac ommon choice in the simulation of organic ligand-protected clusters. [32][33][34][35][36][37] Note that this simplified treatment of the side groups has been demonstrated to show negligible effect on the electronic,optical, and catalytic behaviors when compared to the experimental bulky ligands, since the main optical transition and the catalytic active sites mainly derive from the metals,w hile the contributions from the side groups of the ligands are less significant. It can be seen that the main peak (a peak, 2.04 eV) deviates from the experimental 2.20 eV due to the PBE (Perdew-Burke-Ernzerhof) function, which underestimates the excitation energy.T he main peak primarily comes from HOMO !…”

Homoleptic Alkynyl‐Protected Ag15 Nanocluster with Atomic Precision: Structural Analysis and Electrocatalytic Performance toward CO2 Reduction

“…Figure 1 c presents the simulated absorbance spectrum of [Ag 15 (C≡C−CH 3 ) 12 ] + along with the experimental one. To simplify the calculation, all C≡C‐ t Bu ligands are replaced with C≡C−CH 3 , which has been regarded as a common choice in the simulation of organic ligand‐protected clusters [32–37] . Note that this simplified treatment of the side groups has been demonstrated to show negligible effect on the electronic, optical, and catalytic behaviors when compared to the experimental bulky ligands, since the main optical transition and the catalytic active sites mainly derive from the metals, while the contributions from the side groups of the ligands are less significant.…”

Controllable synthesis and electrocatalytic applications of atomically precise gold nanoclusters

“…Most importantly, the results confirm that the CO 2 RR ability of Au 47 Cd 2 (TBBT) 31 is superior. Cd doped Au NCs show good performance, and other metals like Ag, 112 Pd, 113 and Pt 114 doped Au NCs also have great manifestation on CO 2 RR.…”