Single Ru–N₄ Site-Embedded Porous Carbons for Electrocatalytic Nitrogen Reduction

Abstract

Ammonia is an effective feedstock for chemicals, fertilizers, and energy storage. The electrocatalytic nitrogen reduction reaction (NRR) is an alternative, efficient, and clean technology for ammonia production, relative to the traditional Haber−Bosch method. Singlemetal catalysts are widely studied in the field of NRR. However, very limited conclusions have been made on how to precisely modulate the coordination environment of the single-metalatom sites to boost catalytic NRR performance. Herein, we report a 5,7-membered carbon ringinvolved porous carbon (PC) preparation toward single-atom Ru-embedded PCs. As electrocatalysts, such materials exhibit surprisingly promising catalytic NRR properties with an NH 3 yield rate of up to 67.8 ± 4.9 μg h −1 mg cat −1 and a Faradaic efficiency of 19.5 ± 0.6%, exceeding those of most of the reported single-atom NRR catalysts. Extended X-ray absorption fine structure demonstrates that the presence of topological defects increases the Ru−N bond from 1.48 to 1.56 Å, modulating the coordination environment of the single-atom Ru active sites. Density functional theory-calculated results demonstrate that the adsorption of N 2 onto single-atom Ru surrounded by topological defects extends the N�N bond to 1.146 Å, weakening the strength of N�N and making it susceptible to the NRR. All in all, this work provides a new design strategy by involving topological defects and corresponding large polarization around the Ru single atom to boost the catalytic NRR performance. Such a concept can also be applied to many other kinds of catalysts for energy storage and conversion.

Double–single-atom MoCu-embedded porous carbons boost the electrocatalytic N2 reduction reaction

“…2b). 9,30 The existence of metal–O and lattice oxygen was demonstrated by the XPS O 1s spectra of MoCu@C at 530.2 and 531.7 eV, respectively (Fig. 2c).…”

“…[6][7][8] Due to limitations of the NH 3 yield rate and Faraday efficiency (FE), eNRR is, regrettably, still only at the laboratory development stage. 9,10 To address the industrialization of eNRR, innovative and rational electrocatalytic materials are being developed.…”

Machine Learning Design of Single-Atom Catalysts for Nitrogen Fixation

“…Furthermore, the nitrogen reduction activity of V group metal-based SACs has been verified experimentally. 40,41 Therefore, using the well-performing vanadium group metals (V/Nb/Ta) as centers, we constructed catalyst structures with varying coordination heteroatoms, forming dataset 2. We conducted similar calculations and analyses on this dataset.…”

Unraveling the Activity Trends and Design Principles of Single-Atom Catalysts for Nitrate Electrocatalytic Reduction

“…The NITRR is investigated by a standard three-electrode setup in an H-type electrolytic cell (Figure S6), which is widely used in N species reduction reactions. − Both colorimetric methods (Figure S7) and 1 H nuclear magnetic resonance (NMR) spectra (Figure S8) are performed to quantify NH 3 . We first screen the features of different SAs by analyzing their NITRR activities (Figure a), such as the Ga/NC, Mn/NC, Ru/NC, Ni/NC, Mo/NC, Pd/NC, Pt/NC, and Cu/NC, under the same experimental conditions, which contains 0.5 M Na 2 SO 4 solution (50 mL) and 200 ppm nitrate-N.…”