(233a) Elucidating Doping Effects on the Catalytic Activity of Ligand Protected Gold Nanoclusters for the Electrochemical Reduction of CO2

Ligand-protected gold nanoclusters (LPNCs) are a novel class of nanomaterials that exhibit atomic structural precision and unique physicochemical properties¹. Recently, LPNCs have emerged as promising catalytic nanomaterials, particularly for the electrochemical reduction of CO₂ (CO₂ RR) to CO and H₂ evolution². In order to further tune the properties of gold-based catalytic materials, surface modification through doping (alloying) has shown promise. Owing to their atomic precision and tunable composition, LPNCs have gained attention as model catalysts for understanding the impact of heterometal doping on catalysis. In this work, we investigated the effect of cadmium (Cd) doping on the catalytic activity of the [Au₂₃(SR)₁₆]^1- NC (Au₂₃ NC) and [Au₁₉Cd₂(SR)₁₆]^1- NC (Au₁₉Cd₂ NC). Using density functional theory (DFT) calculations, we unraveled the thermodynamic feasibility of active site formation through partial ligand (-R) removal, which leads to the activation of the Au₁₉Cd₂ NC as an electrocatalyst. Furthermore, the formation of CO (from CO₂ RR) on the undoped Au₂₃ NC was found to be thermodynamically less favorable than on Au₁₉Cd₂ NC by 0.74 eV. Experimental observations show that Cd doping into the Au₂₃ NC enhanced the CO₂ RR activity as well as selectivity by twofold at ~ -0.9 V. Moreover, the Au₁₉Cd₂ NC exhibited the highest CO₂ RR activity among reported gold NCs. With theory and experiments being in excellent agreement, we suggest that Cd doping can boost the CO₂ RR performance of gold NCs. Overall, this work offers detailed fundamental understanding of the catalytic mechanism of CO₂ RR on heterometal doped LPNCs.

References

1. Jin, R.; Zeng, C.; Zhou, M.; Chen, Y. Chemical Reviews 2016, 116, (18), 10346-10413.
2. Austin, N.; Zhao, S.; McKone, J. R.; Jin, R.; Mpourmpakis, G. Catalysis Science & Technology 2018, 8, (15), 3795-3805.