We report single-atom Cu catalysts dispersed on nitrogen-doped carbon by a nitrogen-coordination strategy. The presence of nitrogen enabled good dispersion and attachment of atomic Cu species on the nitrogen-doped carbon frameworks with Cu−N x configurations. The Cu doping concentrations and Cu−N x configurations were well-tuned by the pyrolysis temperature. At a high Cu concentration of 4.9% mol , the distance between neighboring Cu−N x species was close enough to enable C−C coupling and produce C 2 H 4 . In contrast, at Cu concentrations lower than 2.4% mol , the distance between Cu−N x species was large so that the electrocatalyst favored the formation of CH 4 as C 1 products. Density functional theory calculations further confirmed the capability of producing C 2 H 4 by two CO intermediates binding on two adjacent Cu−N 2 sites, while the isolated Cu−N 4 , the neighboring Cu−N 4 , and the isolated Cu−N 2 sites led to formation of CH 4 . Our work demonstrates a facile approach of tuning active Cu sites for CO 2 electroreduction to different hydrocarbons.

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Electrochemical reduction of carbon monoxide (CO) has recently been emerging as a potential alternative for converting carbon emission into high-value multi-carbon products such as acetate. Nonetheless, the activity and selectivity for producing acetate have remained low. Herein, we developed an atomically ordered copper-palladium intermetallic compound (CuPd-IC) structure that achieved a high Faradaic e ciency of 70 ± 5% for CO-to-acetate production with a partial current density of 425 mA•cm − 2 . This corresponded to an acetate production rate of 4.0 mmol•h − 1 •cm − 2 , and 5.3 times of enhancement in acetate production compared to pure Cu. Structural characterizations and density functional theory calculations suggested that CuPd-IC presents a high density of Cu-Pd pairs that act as the active sites to enrich the surface CO coverage, stabilize the surface ethenone as a key acetate-path intermediate, and inhibit hydrogen evolution reaction, thus promoting acetate formation. Using a membrane electrode assembly device, the CuPd-IC catalyst enabled 100 hours of CO-to-acetate operation at 500 mA•cm − 2 and an average acetate Faradaic e ciency of 43%, producing ~ 2 mol acetate.

Monodispersed single metal atoms have been demonstrated with unique potentials for electroreduction of CO2 or CO, while the capability of producing multicarbon (C2+) products is still limited. In this work, we developed a dual metal atomic catalyst with uniform distributions of two adjacent Cu–Cu or Cu–Ni atoms anchored on nitrogen-doped carbon frameworks, featuring distinctive catalytic sites for CO electroreduction. Due to the synergistic effect between adjacent metal sites, the dual Cu–Cu atomic catalyst enables efficient CO electroreduction to C2+ products with an outstanding Faradaic efficiency of ∼91% and a high partial current density over 90 mA·cm–2. In contrast, the dual Cu–Ni atomic catalyst exhibits a remarkably different CO electroreduction selectivity mainly toward CH4. Theoretical calculations suggest that the dual Cu atomic sites facilitate the electroreduction of two CO molecules and subsequent carbon–carbon coupling toward ethylene and acetate, while the replacement of one of the dual Cu atoms with Ni results in too strong CO adsorption, and thus only the single Cu atom functions as the catalytic site for the C1 reduction pathway.