Liquid Nitrogen Sources Assisting Gram‐Scale Production of Single‐Atom Catalysts for Electrochemical Carbon Dioxide Reduction

Abstract

Developing metal-nitrogen-carbon (M-N-C)-based single-atom electrocatalysts for carbon dioxide reduction reaction (CO 2 RR) have captured widespread interest because of their outstanding activity and selectivity. Yet, the loss of nitrogen sources during the synthetic process hinders their further development. Herein, an effective strategy using 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]) as a liquid nitrogen source to construct a nickel single-atom electrocatalyst (Ni-SA) with well-defined Ni-N 4 sites on a carbon support (denoted as Ni-SA-BB/C) is reported. This is shown to deliver a carbon monoxide faradaic efficiency of >95% over a potential of −0.7 to −1.1 V (vs reversible hydrogen electrode) with excellent durability. Furthermore, the obtained Ni-SA-BB/C catalyst possesses higher nitrogen content than the Ni-SA catalyst prepared by conventional nitrogen sources. Importantly, only thimbleful Ni nanoparticles (Ni-NP) are contained in the large-scale-prepared Ni-SA-BB/C catalyst without acid leaching, and with only a slight decrease in the catalytic activity. Density functional theory calculations indicate a salient difference between Ni-SA and Ni-NP in the catalytic performance toward CO 2 RR. This work introduces a simple and amenable manufacturing strategy to large-scale fabrication of nickel single-atom electrocatalysts for CO 2 -to-CO conversion.

Fabrication of Nickel Single Atoms with Ionic Liquids by Only One-Step Pyrolysis for CO2 Electroreduction

“…When [BMIM]BF 4 is employed to be the nitrogen source to form N-doped carbon, the additional carbon source is essential. In previous work, sodium citrate is taken as the carbon source to synthesize Ni-SA-BB/C along with [BMIM]BF 4 as the nitrogen source . Here, the cooperation of [BMIM]BF 4 and [BMIM]DCN prompts the formation of N-doped carbon materials, in which [BMIM]BF 4 and [BMIM]DCN are mainly the nitrogen source and carbon source, respectively.…”

Nickel Single Atom Density‐Dependent CO2 Efficient Electroreduction

“…Furthermore, the wavelet transform (WT) of EXAFS data revealed that both 12.5 Ni 1 @NG-900 and NiPc exhibited similar contour plot, with only one intensity maximum at 7.0 Å instead of the Ni-Ni interaction at 8.4 Å. This indicates that the dispersed Ni atoms in 12.5 Ni 1 @NG-900 were coordinated with Ni─N coordination, [55,56] confirming the presence of atomically dispersed Ni species with a NiN 4 moiety. This finding is in good agreement with the results obtained from SACTEM and XPS analysis.…”

Electron Tug Effect in Ni Single Atoms for Carbon Dioxide Electroreduction over a Wide Potential Range

“…17 3d). 25,42,43 In the inset of Fig. 3d, the pre-edge feature peak at approximately 8330 eV is assigned to the 1s → 3d transition of the central Ni atoms.…”