Copper Doping Boosts Electrocatalytic CO2 Reduction of Atomically Precise Gold Nanoclusters

Guocheng Deng; Hyewon Yun; Megalamane S Bootharaju; Fang Sun; Kangjae Lee; Xiaolin Liu; Seungwoo Yoo; Qing Tang; Yun Jeong Hwang; Taeghwan Hyeon

doi:10.1021/jacs.3c08438

Copper Doping Boosts Electrocatalytic CO₂ Reduction of Atomically Precise Gold Nanoclusters

J Am Chem Soc. 2023 Dec 20;145(50):27407-27414. doi: 10.1021/jacs.3c08438. Epub 2023 Dec 6.

Authors

Guocheng Deng^{1

2}, Hyewon Yun^{1

3}, Megalamane S Bootharaju^{1

2}, Fang Sun⁴, Kangjae Lee^{1

2}, Xiaolin Liu^{1

2}, Seungwoo Yoo^{1

2}, Qing Tang⁴, Yun Jeong Hwang^{1

3}, Taeghwan Hyeon^{1

2}

Affiliations

¹ Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.
² School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea.
³ Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea.
⁴ School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China.

PMID: 38055351
DOI: 10.1021/jacs.3c08438

Abstract

Unraveling the atomistic synergistic effects of nanoalloys on the electrocatalytic CO₂ reduction reaction (eCO₂RR), especially in the presence of copper, is of paramount importance. However, this endeavor encounters significant challenges due to the lack of the crystallographically determined atomic-level structure of appropriate monometallic and bimetallic analogues. Herein, we report a one-pot synthesis and structure characterization of a AuCu nanoalloy cluster catalyst, [Au₁₅Cu₄(DPPM)₆Cl₄(C≡CR)₁]²⁺ (denoted as Au₁₅Cu₄). Single-crystal X-ray diffraction analysis reveals that Au₁₅Cu₄ comprises two interpenetrating incomplete, centered icosahedra (Au₉Cu₂ and Au₈Cu₃) and is protected by six DPPM, four halide, and one alkynyl ligand. The Au₁₅Cu₄ cluster and its closest monometal structural analogue, [Au₁₈(DPPM)₆Br₄]²⁺ (denoted as Au₁₈), as model systems, enable the elucidation of the atomistic synergistic effects of Au and Cu on eCO₂RR. The results reveal that Au₁₅Cu₄ is an excellent eCO₂RR catalyst in a gas diffusion electrode-based membrane electrode assembly (MEA) cell, exhibiting a high CO Faradaic efficiency (FE_CO) of >90%, and this efficiency is substantially higher than that of the undoped Au₁₈ (FE_CO: 60% at -3.75 V). Au₁₅Cu₄ exhibits an industrial-level CO partial current density of up to -413 mA/cm² at -3.75 V with the gas CO₂-fed MEA, which is 2-fold higher than that of Au₁₈. The density functional theory (DFT) calculations demonstrate that the synergistic effects are induced by Cu doping, where the exposed pair of AuCu dual sites was suggested for launching the eCO₂RR process. Besides, DFT simulations reveal that these special dual sites synergistically coordinate a moderate shift in the d-state, thus enhancing its overall catalytic performance.