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The development of highly efficient robust electrocatalysts with low overpotential and industrial‐level current density is of great significance for CO2 electroreduction (CO2ER), however the low proton transport rate during the CO2ER remains a challenge. Herein, a porous N‐doped carbon nanofiber confined with tin‐nitrogen sites (Sn/NCNFs) catalyst is developed, which is prepared through an integrated electrospinning and pyrolysis strategy. The optimized Sn/NCNFs catalyst exhibits an outstanding CO2ER activity with the maximum CO FE of 96.5%, low onset potential of −0.3 V, and small Tafel slope of 68.8 mV dec−1. In a flow cell, an industrial‐level CO partial current density of 100.6 mA cm−2 is achieved. In situ spectroscopic analysis unveil the isolated SnN site acted as active center for accelerating water dissociation and subsequent proton transport process, thus promoting the formation of intermediate *COOH in the rate‐determining step for CO2ER. Theoretical calculations validate pyrrolic N atom adjacent to the SnN active species assisted reducing the energy barrier for *COOH formation, thus boosting the CO2ER kinetics. A Zn‐CO2 battery is designed with the cathode of Sn/NCNFs, which delivers a maximum power density of 1.38 mW cm−2 and long‐term stability. [ABSTRACT FROM AUTHOR]

Unlocking of the extremely inert C=O bond during electrochemical CO2 reduction demands subtle regulation on a key "resource", protons, necessary for intermediate conversion but also readily trapped in water splitting, which is still challenging for developing efficient single-atom catalysts limited by their structural simplicity usually incompetent to handle this task. Incorporation of extra functional units should be viable. Herein, a proton deployment strategy is demonstrated via "atomic and nanostructured iron (A/N-Fe) pairs", comprising atomically dispersed iron active centers spin-polarized by nanostructured iron carbide ferromagnets, to boost the critical protonation steps. The as-designed catalyst displays a broad window (300 mV) for CO selectivity > 90% (98% maximum), even outperforming numerous cutting-edge M—N—C systems. The well-placed control of proton dynamics by A/N-Fe can promote *COOH/*CO formation and simultaneously suppress H2 evolution, benefiting from the magnetic-proximity-induced exchange splitting (spin polarization) that properly adjusts energy levels of the Fe sites' d-shells, and further those of the adsorbed intermediates' antibonding molecular orbitals. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts show great promise as non‐precious electrocatalysts for CO2 electroreduction reaction (CO2ER). However, it is still challenging to gain a fundamental understanding of the complicated dynamic behavior of CO2 activation to achieve high product selectivity. Herein, the authors report an unusual iron single‐atom catalyst, containing atomically dispersed Fe–N4 species and Fe3C nanoparticles (NPs) (Fe3C|Fe1N4). Having a fragmental‐rock‐shaped nanocarbon architecture, isolated Fe–N4 sites uniformly disperse with adjacent Fe3C NPs (<30 nm) in a carbon matrix. Benefiting from the strong coupling effect between Fe3C and Fe1N4 and unique spatial nanostructure, Fe3C|Fe1N4 displays exceptional CO2ER activity with a low onset potential of −0.3 V and high Faradaic efficiency of 94.6% at −0.5 V for CO production, acting as one of the most active Fe–N–C catalysts and even exceeding most other carbon supported non‐precious metal NPs. Experimental observations discover that the excellent CO2ER activity of Fe3C|Fe1N4 catalyst is attributable to the presence of Fe3C NPs that optimizes JCO of the coexisted Fe–N4 active sites. In situ attenuated total reflectance‐Fourier transform infrared analysis and theoretical calculations reveal that the Fe3C NPs strengthen the adsorption of CO2 on the isolated Fe–N4 sites to accelerate the formation of *COOH intermediate, and hence enhance the whole CO2ER performance. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO2 (CO2RR) to value‐added chemicals is of great significance for CO2 utilization, however the CO2RR process involving multi‐electron and proton transfer is greatly limited by poor selectivity and low yield. Herein, We have developed an atomically dispersed monovalent zinc catalyst anchored on nitrogenated carbon nanosheets (Zn/NC NSs). Benefiting from the unique coordination environment and atomic dispersion, the Zn/NC NSs exhibit a superior CO2RR performance, featuring a high current density up to 50 mA cm−2 with an outstanding CO Faradaic efficiency of ≈95 %. The center ZnI atom coordinated with three N atoms and one N atom that bridges over two adjacent graphitic edges (Zn‐N3+1) is identified as the catalytically active site. Experimental results reveal that the twisted Zn‐N3+1 structure accelerates CO2 activation and protonation in the rate‐determining step of *CO2 to *COOH, while theoretical calculations elucidate that atomically dispersed Zn‐N3+1 moieties decrease the potential barriers for intermediate COOH* formation, promoting the proton‐coupled CO2RR kinetics and boosting the overall catalytic performance. [ABSTRACT FROM AUTHOR]

Developing single‐atom electrocatalysts with high activity and superior selectivity at a wide potential window for CO2 reduction reaction (CO2RR) still remains a great challenge. Herein, a porous NiNC catalyst containing atomically dispersed NiN4 sites and nanostructured zirconium oxide (ZrO2@Ni‐NC) synthesized via a post‐synthetic coordination coupling carbonization strategy is reported. The as‐prepared ZrO2@Ni‐NC exhibits an initial potential of −0.3 V, maximum CO Faradaic efficiency (F.E.) of 98.6% ± 1.3, and a low Tafel slope of 71.7 mV dec−1 in electrochemical CO2RR. In particular, a wide potential window from −0.7 to −1.4 V with CO F.E. of above 90% on ZrO2@Ni‐NC far exceeds those of recently developed state‐of‐the‐art CO2RR electrocatalysts based on NiN moieties anchored carbon. In a flow cell, ZrO2@Ni‐NC delivers a current density of 200 mA cm−2 with a superior CO selectivity of 96.8% at −1.58 V in a practical scale. A series of designed experiments and structural analyses identify that the isolated NiN4 species act as real active sites to drive the CO2RR reaction and that the nanostructured ZrO2 largely accelerates the protonation process of *CO2− to *COOH intermediate, thus significantly reducing the energy barrier of this rate‐determining step and boosting whole catalytic performance. [ABSTRACT FROM AUTHOR]

Developing highly efficient carbon aerogels (CA) electrocatalysts based on transition metal‐nitrogen sites is critical for the CO2 electroreduction reaction (CO2RR). However, simultaneously achieving a high current density and high Faradaic efficiency (FE) still remains a big challenge. Herein, a series of unique 3D hierarchical cross‐linked nanostructured CA with metal‐nitrogen sites (MN, M = Ni, Fe, Co, Mn, Cu) is developed for efficient CO2RR. An optimal CA/N‐Ni aerogel, featured with unique hierarchical porous structure and highly exposed M‐N sites, exhibits an unusual CO2RR activity with a CO FE of 98% at −0.8 V. Notably, an industrial current density of 300 mA cm−2 with a high FE of 91% is achieved on CA/N‐Ni aerogel in a flow‐cell reactor, which outperforms almost all previously reported M‐N/carbon based catalysts. The CO2RR activity of different CA/N‐M aerogels can be arranged as Ni, Fe, Co, Mn, and Cu from high to low. In situ spectroelectrochemistry analyses validate that the rate‐determining step in the CO2RR is the formation of *COOH intermediate. A ZnCO2 battery is further assembled with CA/N‐Ni as the cathode, which shows a maximum power density of 0.5 mW cm−2 and a superior rechargeable stability. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO 2 (CO 2 RR) to value-added chemicals is of great significance for CO 2 utilization, however the CO 2 RR process involving multi-electron and proton transfer is greatly limited by poor selectivity and low yield. Herein, We have developed an atomically dispersed monovalent zinc catalyst anchored on nitrogenated carbon nanosheets (Zn/NC NSs). Benefiting from the unique coordination environment and atomic dispersion, the Zn/NC NSs exhibit a superior CO 2 RR performance, featuring a high current density up to 50 mA cm -2 with an outstanding CO Faradaic efficiency of ≈95 %. The center Zn I atom coordinated with three N atoms and one N atom that bridges over two adjacent graphitic edges (Zn-N 3+1 ) is identified as the catalytically active site. Experimental results reveal that the twisted Zn-N 3+1 structure accelerates CO 2 activation and protonation in the rate-determining step of *CO 2 to *COOH, while theoretical calculations elucidate that atomically dispersed Zn-N 3+1 moieties decrease the potential barriers for intermediate COOH* formation, promoting the proton-coupled CO 2 RR kinetics and boosting the overall catalytic performance., (© 2021 Wiley-VCH GmbH.)