Simultaneously Integrate Iron Single Atom and Nanocluster Triggered Tandem Effect for Boosting Oxygen Electroreduction

Abstract

Atomically nitrogen‐coordinated iron atoms on carbon (FeNC) catalysts are emerging as attractive materials to substitute precious‐metal‐based catalysts for the oxygen reduction reaction (ORR). However, FeNC usually suffers from unsatisfactory performance due to the symmetrical charge distribution around the iron site. Elaborately regulating the microenvironment of the central Fe atom can substantially improve the catalytic activity of FeNC, which remains challenging. Herein, N/S co‐doped porous carbons are rationally prepared and are verified with rich Fe‐active sites, including atomically dispersed FeN4 and Fe nanoclusters (FeSA‐FeNC@NSC), according to systematically synchrotron X‐ray absorption spectroscopy analysis. Theoretical calculation verifies that the contiguous S atoms and Fe nanoclusters can break the symmetric electronic structure of FeN4 and synergistically optimize 3d orbitals of Fe centers, thus accelerating OO bond cleavage in OOH* for improving ORR activity. The FeSA‐FeNC@NSC delivers an impressive ORR activity with half‐wave‐potential of 0.90 V, which exceeds that of state‐of‐the‐art Pt/C (0.87 V). Furthermore, FeSA‐FeNC@NSC‐based Zn‐air batteries deliver excellent power densities of 259.88 and 55.86 mW cm–2 in liquid and all‐solid‐state flexible configurations, respectively. This work presents an effective strategy to modulate the microenvironment of single atomic centers and boost the catalytic activity of single‐atom catalysts by tandem effect.

Constructing atomically-dispersed Mn on ZIF-derived nitrogen-doped carbon for boosting oxygen reduction

“…NC has the united rhombic dodecahedron shape with the mean size of ∼ 400 nm, which is in agreement with that of ZIF-8. Since the N atoms doped in NC could function as anchors to adsorb MnAc molecules, NC successfully adsorbed MnAc in isopropanol solution to form MnAc/NC ( Huo et al, 2020 ; Qu et al, 2021 ; Zhai et al, 2022 ), which was then further pyrolyzed at 900°C. The obtained black power was washed by 3 M HCl solution to etch the unstable metal particles, then annealed again at 900°C for 1 h in N 2 condition to recover the crystallinity, forming Mn-N x /NC which possesses highly-dispersed Mn-N x active sites.…”

Emerging single-atom iron catalysts for advanced catalytic systems

“…When the Tafel slope is greater than 100 mV dec −1 , the RDS is the formation of the OH* intermediate in the first electron transfer step. 61,155,156…”

“…When the Tafel slope is greater than 100 mV dec À1 , the RDS is the formation of the OH* intermediate in the first electron transfer step. 61,155,156 Research results showed that when Fe, Co, and Ni are used as catalysts, the OER catalytic effect follows the order of Ni 4 Co 4 Fe. According to DFT calculation, it was found that N doping will cause the redistribution of the charge of the carbon material.…”

Steering Local Electronic Configuration of Fe–N–C‐Based Coupling Catalysts via Ligand Engineering for Efficient Oxygen Electroreduction

“…catalysts [ 11–15 ] have received significant attention thanks to their maximum atom utilization efficiency, adjustable electronic configurations, and excellent catalytic performance. [ 16–24 ] Particularly, Fe–N–C catalysts, predominantly comprising with Fe‐N 4 sites, deliver remarkable significant ORR activity and selectivity. [ 25–28 ] Nevertheless, significant performance disparity still exists between Fe–N–C catalysts and platinum‐group‐based catalysts, on account of the symmetric electron distribution in Fe–N 4 active sites result in unsuitable free energy for the adsorption/desorption of oxygen intermediates and in turn badly decrease the kinetic activity.…”