Atomic Iron Research Articles

Construction of N-Fe-S bridge in atomic iron catalyst for boosting Fenton-like reactions

Constructing the coordination environment of single-atom catalysts (SACs) can be an attractive technical strategy to regulate the generation of reactive oxygen species for Fenton-like reactions. Herein, we have constructed an asymmetric coordination of Fe single-atom catalyst (FeSA-NS-PCNS) with abundant N-Fe-S bridge (FeSA-N3S1) for robust Fenton-like reactions. 82.5 % of singlet oxygen (1O2) selectivity and high turnover frequency of bisphenol A degradation (0.568 min−1) were achieved at mild conditions. Experimental works and theoretical analyses illustrated that S doping breaks the inert environment of the original N-Fe-N symmetric coordination equilibrium and modulates the electron density of the atomic Fe center, which is beneficial for boosting PMS adsorption and reducing the energy barriers of vital *OH and *O intermediates. The coupling between the FeSA-N3S1 interface and peroxymonosulfate molecule boosts in-situ electron transfer through the N-Fe-S bridge, which induces more electron flow from the low valence Fe to OH* on the surface of Fe-*O-H, forming a high yield of 1O2. Moreover, we designed the Fenton-like reactions by FeSA-NS-PCNS membrane reactor for an efficient contaminant removal rate of over 90 % even after 11 cycles. This work provides a novel perspective on developing SACs with asymmetric coordination to regulate reactive oxygen species for the treatment of organic contaminants in water bodies.

Challenges and Opportunities in Preparing Fe-N-C Layers Supported on Non-Carbon Supports

Global energy demand will be continuously rising in the foreseeable future. To mitigate the results of climate change it is necessary to reduce the emittance of greenhouse gases. One promising approach is to switch to hydrogen as energy carrier and use proton exchange membrane fuel cells (PEMFCs) to efficiently convert H2 into electric power. Here, hydrogen and oxygen/air are used to directly generate electrical energy with only water as byproduct. Both reactions need to happen efficiently at the same time. The oxygen reduction reaction (ORR), however, is a very sluggish four-electron-reaction and needs efficient catalysts.The state-of-the-art ORR catalyst in PEMFC is platinum but that is a very scarce and expensive metal. Hence, it is important to switch to precious-metal-group (PGM) free catalysts. In recent years, bio inspired iron-based FeNC catalysts have been shown to approach ORR activities that are competitive with those of platinum, even though they need a higher catalyst loading than Pt to reach the desired high current densities.1–3 Those catalysts feature single Fe atoms surrounded by four N atoms in graphitic carbon. The drawback of those materials is their lower stability compared to PGM materials. In a nutshell, the carbon matrix oxidizes during operation in PEMFCs, changing the morphology of the catalytic center and rendering it less active, or inactive, depending on the carbon oxidation extent. Direct demetallation phenomena are also possible, leaving a N4 cavity without metal cation center. It was shown recently by Wu et al.4 that it is possible to raise durability by adding an additional carbon layer on the catalyst. One alternative approach to reduce those degradations is to interface Fe-N4 sites with a carbon-free support. The targeted support material must be immune to corrosion in acid and withstand the typical ORR electrochemical potentials. It also has to be electrically conductive to facilitate electron transfers, both locally and on long scale.In this work, conductive ceramic metal oxide materials (Ta doped SnO2, TTO) was investigated as a possible alternative catalyst supports. This material is resistant to acid and can withstand prolonged potentials at operating conditions in PEMFCs.5 During the synthesis of the FeNC catalysts, high temperatures are generally applied. Such treatments can be detrimental to the conductivity of ceramics due to metal aggregation (in case of doped materials) and may also lead to morphological changes as well as the reduction of the ceramics to metallic materials. A robust method to synthesize FeNC catalysts is by mixing the separate Fe, N and C precursors and using optimized thermal treatment. In this study, the effect of the pyrolysis conditions as well as the ratio of FeNC precursors to TTO was investigated with various characterization methods, e.g. X-ray absorption spectroscopy, Mossbauer spectroscopy, and high resolution TEM. The characterization techniques confirm the presence of single atom Fe as well as different Sn species that might contribute to the activity. The resulting materials were electrochemically characterized with rotating disc electrode techniques and in PEM fuel cells for their ORR-activity and durability. It was shown that the activity of materials with a high FeNC precursor content relative to TTO can outperform a reference FeNC synthesized similarly but without TTO, in both RDE (Figure) and PEMFC.The presentation will report in detail the effects of pyrolysis conditions and FeNC precursor/TTO content on the structure, activity and stability of materials.(1) Mehmood, A. et al. High Loading of Single Atomic Iron Sites in Fe–NC Oxygen Reduction Catalysts for Proton Exchange Membrane Fuel Cells. Nat. Catal. 2022, 5 (4), 311–323. https://doi.org/10.1038/s41929-022-00772-9.(2) Gasteiger, H. A.; Marković, N. M. Just a Dream—or Future Reality? Science 2009, 324 (5923), 48–49. https://doi.org/10.1126/science.1172083.(3) Zion, N. et al.. Electrocatalysis of Oxygen Reduction Reaction in a Polymer Electrolyte Fuel Cell with a Covalent Framework of Iron Phthalocyanine Aerogel. ACS Appl. Energy Mater. 2022, 5 (7), 7997–8003. https://doi.org/10.1021/acsaem.2c00375.(4) Liu, S.et al. Atomically Dispersed Iron Sites with a Nitrogen–Carbon Coating as Highly Active and Durable Oxygen Reduction Catalysts for Fuel Cells. Nat. Energy 2022, 7 (7), 652–663. https://doi.org/10.1038/s41560-022-01062-1.(5) Jiménez-Morales, et al. Strong Interaction between Platinum Nanoparticles and Tantalum-Doped Tin Oxide Nanofibers and Its Activation and Stabilization Effects for Oxygen Reduction Reaction. ACS Catal. 2020, 10 (18), 10399–10411. https://doi.org/10.1021/acscatal.0c02220. Figure 1

The Optical Spectra of Hydrogen Plasma Smelting Reduction of Iron Ore: Application and Requirements

Due to the ever‐increasing demand for high‐quality steel and the need to reduce CO2 emissions, research and development of sustainable steelmaking processes have gained a lot of interest in the past decade. One of these processes is the hydrogen plasma smelting reduction (HPSR), which has proven to be a promising solution for iron ore reduction where water vapor is formed instead of CO2. However, due to the highly dynamic and sometimes unpredictable behavior of plasmas and their nonlinear interaction with the liquid oxides, the monitoring and control of the underlying processes must be improved. This article explores the usage of optical emission spectroscopy (OES) and image analysis for HPSR process monitoring at laboratory and pilot scale. The results cover the time evolution of the OES and camera data with the focus on the most interesting radiating species, such as atomic hydrogen, iron, and oxygen together with the FeO molecule. In addition, the advantages, disadvantages, and requirements of these methods for HPSR process monitoring are discussed.

Harmonizing Enzyme-like Cofactors to Boost Nanozyme Catalysis.

Engineering isolated metal sites resembling the primary coordination sphere of metallocofactors enables atomically dispersed materials as promising nanozymes. However, most existing nanozymes primarily focus on replicating specific metallocofactors while neglecting other supporting cofactors within active pockets, leading to reduced electron transfer (ET) efficiency and thus inferior catalytic performances. Herein, we report a metal-organic framework UiO-67 nanozyme with atomically dispersed iron sites, which involves multiple tailored enzyme-like nanocofactors that synergistically drive the ET process for enhanced peroxidase-like catalysis. Among them, the linker-coupled atomic iron site plays a critical role in substrate activation, while bare linkers and zirconia nodes facilitate the ET efficiency of intermediates. The synergy of three nanocofactors results in a 4.29-fold enhancement compared with the single effort of isolated metal site-based nanocofactor, holding promise in immunoassay for sensitive detection of chlorpyrifos. This finding opens a new way for designing high-performance nanozymes by harmonizing various nanocofactors at the atomic and molecular scale.

Harmonizing Enzyme‐like Cofactors to Boost Nanozyme Catalysis

AbstractEngineering isolated metal sites resembling the primary coordination sphere of metallocofactors enables atomically dispersed materials as promising nanozymes. However, most existing nanozymes primarily focus on replicating specific metallocofactors while neglecting other supporting cofactors within active pockets, leading to reduced electron transfer (ET) efficiency and thus inferior catalytic performances. Herein, we report a metal–organic framework UiO‐67 nanozyme with atomically dispersed iron sites, which involves multiple tailored enzyme‐like nanocofactors that synergistically drive the ET process for enhanced peroxidase‐like catalysis. Among them, the linker‐coupled atomic iron site plays a critical role in substrate activation, while bare linkers and zirconia nodes facilitate the ET efficiency of intermediates. The synergy of three nanocofactors results in a 4.29‐fold enhancement compared with the single effort of isolated metal site‐based nanocofactor, holding promise in immunoassay for sensitive detection of chlorpyrifos. This finding opens a new way for designing high‐performance nanozymes by harmonizing various nanocofactors at the atomic and molecular scale.

Triggering the electronic microenvironment of extraordinary nitrogen-bridged atomic iron coordinated with in-plane nitrogen by manipulating phase-reconfigured 2D vanadium nitride MXenes toward invigorated lithium–sulfur batteries

The electronic microenvironment of isolated Fe in FeN4-O-NC-VN was modulated by axial-bridged nitrogen-doped carbon for bidirectional lithium–sulfur batteries.

Spectroscopy of a mesospheric ghost reveals iron emissions

Mesospheric Green emissions from excited Oxygen in Sprite Tops (ghosts) are infrequent and faint greenish transient luminous events that remain for hundreds of milliseconds on top of certain energetic sprites. The main hypothesis to explain this glow persistence is the long lifetime of excited atomic oxygen at 557.73 nm, a well-known emission line in aurora and airglow. However, due to the lack of spectroscopic campaigns to analyse such events to date, the species involved in the process can not yet be identified. Here we report observational results showing the temporal evolution of a ghost spectrum between 500 nm and 600 nm. Besides weak -but certain- traces of excited atomic oxygen, our results show four main contributors related to the slow decay of the glow: atomic iron and nickel, molecular nitrogen and ionic molecular oxygen. Additionally, we are able to identify traces of atomic sodium, and ionic silicon, these observations being consistent with previous direct measurements of density profiles of meteoric metals in the mesosphere and lower thermosphere. This finding calls for an upgrade of current air plasma kinetic understanding under the influence of transient luminous events.

Interfacial "Single-Atom-in-Defects" Catalysts Accelerating Li+ Desolvation Kinetics for Long-Lifespan Lithium-Metal Batteries.

The lithium-metal anode is a promising candidate for realizing high-energy-density batteries owing to its high capacity and low potential. However, several rate-limiting kinetic obstacles, such as the desolvation of Li+ solvation structure to liberate Li+ , Li0 nucleation, and atom diffusion, cause heterogeneous spatial Li-ion distribution and fractal plating morphology with dendrite formation, leading to low Coulombic efficiency and depressive electrochemical stability. Herein, differing from pore sieving effect or electrolyte engineering, atomic iron anchors to cation vacancy-rich Co1- x S embedded in 3D porous carbon (SAFe/CVRCS@3DPC) isproposed and demonstrated as catalytic kinetic promoters. Numerous free Li ions are electrocatalytically dissociated from the Li+ solvation complex structure for uniform lateral diffusion by reducing desolvation and diffusion barriers via SAFe/CVRCS@3DPC, realizing smooth dendrite-free Li morphologies, as comprehensively understood by combined insitu/exsitu characterizations. Encouraged by SAFe/CVRCS@3DPC catalytic promotor, the modified Li-metal anodes achieve smooth plating with a long lifespan (1600h) and high Coulombic efficiency without any dendrite formation. Paired with the LiFePO4 cathode, the full cell (10.7mgcm-2 ) stabilizes a capacity retention of 90.3% after 300 cycles at 0.5C, signifying the feasibility of using interfacial catalysts for modulating Li behaviors toward practical applications.

Single‐atom Iron Catalyst with Biomimetic Active Center to Accelerate Proton Spillover for Medical‐level Electrosynthesis of H2O2Disinfectant

AbstractElectrosynthesis of H2O2has great potential for directly converting O2into disinfectant, yet it is still a big challenge to develop effective electrocatalysts for medical‐level H2O2production. Herein, we report the design and fabrication of electrocatalysts with biomimetic active centers, consisting of single atomic iron asymmetrically coordinated with both nitrogen and sulfur, dispersed on hierarchically porous carbon (FeSA‐NS/C). The newly‐developed FeSA‐NS/C catalyst exhibited a high catalytic activity and selectivity for oxygen reduction to produce H2O2at a high current of 100 mA cm−2with a record high H2O2selectivity of 90 %. An accumulated H2O2concentration of 5.8 wt.% is obtained for the electrocatalysis process, which is sufficient for medical disinfection. Combined theoretical calculations and experimental characterizations verified the rationally‐designed catalytic active center with the atomic Fe site stabilized by three‐coordinated nitrogen atoms and one‐sulfur atom (Fe‐N3S‐C). It was further found that the replacement of one N atom with S atom in the classical Fe‐N4‐C active center could induce an asymmetric charge distribution over N atoms surrounding the Fe reactive center to accelerate proton spillover for a rapid formation of the OOH* intermediate, thus speeding up the whole reaction kinetics of oxygen reduction for H2O2electrosynthesis.

Single-atom Iron Catalyst with Biomimetic Active Center to Accelerate Proton Spillover for Medical-level Electrosynthesis of H2 O2 Disinfectant.

Electrosynthesis of H2 O2 has great potential for directly converting O2 into disinfectant, yet it is still a big challenge to develop effective electrocatalysts for medical-level H2 O2 production. Herein, we report the design and fabrication of electrocatalysts with biomimetic active centers, consisting of single atomic iron asymmetrically coordinated with both nitrogen and sulfur, dispersed on hierarchically porous carbon (FeSA -NS/C). The newly-developed FeSA -NS/C catalyst exhibited a high catalytic activity and selectivity for oxygen reduction to produce H2 O2 at a high current of 100 mA cm-2 with a record high H2 O2 selectivity of 90 %. An accumulated H2 O2 concentration of 5.8 wt.% is obtained for the electrocatalysis process, which is sufficient for medical disinfection. Combined theoretical calculations and experimental characterizations verified the rationally-designed catalytic active center with the atomic Fe site stabilized by three-coordinated nitrogen atoms and one-sulfur atom (Fe-N3 S-C). It was further found that the replacement of one N atom with S atom in the classical Fe-N4 -C active center could induce an asymmetric charge distribution over N atoms surrounding the Fe reactive center to accelerate proton spillover for a rapid formation of the OOH* intermediate, thus speeding up the whole reaction kinetics of oxygen reduction for H2 O2 electrosynthesis.

Boosting oxygen reduction of single atomic iron sites by charge redistribution

Atomically dispersed porphyrin-type iron catalysts have demonstrated great potential to substitute platinum group metals for the oxygen reduction reaction (ORR), yet being subjected to limited active sites and sluggish O2 activation kinetics over the symmetrical planar four-coordinated FeN4 structure. Herein, the charge regulation on FeN4 site is achieved via non-bonding interaction of adjacent nitrogen over high-loading single atomic Fe catalysts to boost their intrinsic ORR activity. The single atomic Fe catalysts exhibit excellent alkaline ORR activity with a half-wave potential of 0.914 V versus reversible hydrogen electrode and tenfold higher kinetic current density than that of Pt/C catalysts. Both experimental and theoretical studies confirm that the secondary nitrogen compensation can anchor greater Fe atoms up to 5.44 wt% with sufficient O2 activation sites and simultaneously break the symmetrical charge distribution of FeN4 site to optimize the adsorption/desorption of oxygen intermediate for accelerating ORR kinetics. Moreover, the single atomic Fe catalysts demonstrate great practical application in liquid and solid zinc-air batteries with long-term cycling stability for 600 and 150 h, respectively, as well as superior flexibility in solid batteries.

Atomic iron on porous graphene films for catalyzing the VO2+/VO2+ redox couple in vanadium redox flow batteries

The electrocatalytic activity of the electrode materials towards the vanadium redox couples is a major factor in determining the performance of vanadium redox flow batteries (VRFBs). Herein, we report the employment of iron single atoms supported on a monolithic porous graphene film (Fe1-PGF) as electrodes for catalyzing the VO2+/VO2+ redox couple. The high intrinsic catalytic activity of the atomic Fe sites, the superior surface hydrophilicity, along with the enhanced mass transfer efficiency and exposure of active sites benefited from the porous structure, endow the Fe1-PGF electrode with improved electrochemical performance compared to metal-free PGF counterpart and commercial graphite felt electrode. Consequently, the single-cell battery assembled with Fe1-PGF exhibits a high voltage efficiency (77.96%) and energy efficiency (70.27%) at the current density of 60 mA cm−2 as well as lower overpotential and higher rate capability compared to the control samples. This study demonstrates that single atom catalysts (SACs) are promising candidates for catalyzing the vanadium redox couples in VRFBs and motivates the exploration of SACs in other types of redox flow batteries.

Double Riveting and Steric Hindrance Strategy for Ultrahigh‐Loading Atomically Dispersed Iron Catalysts Toward Oxygen Reduction

Atomically dispersed iron on nitrogen doped carbon displays high intrinsic activity toward oxygen reduction reaction, and has been identified as an attractive candidate to precious platinum catalysts. However, the loading of atomic iron sites is generally limited to below 4 wt% due to the undesired formation of iron-related particles at higher contents. Herein, this work overcomes this limit by a double riveting and steric hindrance strategy to achieve monodispersed iron with a high-loading of 12.8 wt%. Systematic study reveals that chemical riveting of atomic iron in ZIF-8 framework, chelation of Fe ions with interconfined 1,4-phenylenebisboronic, and physical hindrance are essential to obtain high-loading monodispersed Fe moieties. Resultantly, designed Fe-N-C-PDBA exhibits superior catalytic activity and excellent stability over commercial platinum catalysts toward oxygen reduction reaction in both half-cells and zinc-air fuel cells (ZAFCs). This provides an avenue for developing high-loading single-atom catalysts (SACs) for energy devices.

Generalized Encapsulations of ZIF-Based Fe-N-C Catalysts with Controllable Nitrogen-Doped Carbon for Significantly-Improved Stability Toward Oxygen Reduction Reaction.

The vigorous development of efficient platinum group metal-free catalysts is considerably important to facilitate the universal application of proton exchange membrane fuel cells. Although nitrogen-coordinated atomic iron intercalated in carbon matrix (Fe-N-C) catalysts exhibit promising catalytic activity, the performance in fuel cells, especially the short lifetime, remains an obstacle. Herein, a highly-active Fe-N-C catalyst with a power density of >1 w cm-2 and prolonged discharge stability with a current density of 357 mA cm-2 after 40 h of constant voltage discharge at 0.7 V in H2 -O2 fuel cells using a controllable and efficient N-C coating strategy is developed. It is clarified that a thicker N-C coating may be more favorable to enhance the stability of Fe-N-C catalysts at the expense of their catalytic activity. The stability enhancement mechanism of the N-C coating strategy is proven to be the synergistic effect of reduced carbon corrosion and iron loss. It is believed that these findings can contribute to the development of Fe-N-C catalysts with high activity and long lifetimes.

Single-Atom iron catalyst activating peroxydisulfate for efficient organic contaminant degradation relying on electron transfer

Single-atom iron catalysts (SACs) have drawn extensive attention in advanced oxidation processes (AOPs) because of their tunable electron feature. Although single-atomic metal activation has been developed to optimize the organic contaminant oxidation and understand the associated mechanism governing persulfate-based AOPs, studies on peroxydisulfate (PDS) are rare. Herein, atomic iron was anchored in Enteromorpha-derived carbon matrices via a novel and cost-effective route in this work. This single atomic catalyst (FeSA-NEPBC) exhibited very high activity in PDS conversion for organic pollutant oxidation. Integrated with radical quenching experiments and electron spin resonance (ESR), the nonradical pathways of pollutant degradation was unveiled to be an electron-transfer process. Electrochemical analysis, masking experiments and theoretical calculations unraveled that FeSA-NEPBC/PDS* complex and Fe-pyridinic N4 moiety were the predominant oxidizing intermediate and active sites, respectively. The innovative application of galvanic oxidation process (GOP) was also employed to probe the mechanism. Bisphenol S (BPS) was degraded only when the catalyst-coating the graphite sheets was applied in the GOP, further confirming the occurrence of electron transfer. Moreover, the FeSA-NEPBC/PDS system exhibited favorable performance in realistic wastewater remediation scenarios. This work offers a better mechanistic understanding of PDS activation by the single-atom catalysts, while providing keen insights into the design of stable atomic metal catalysts for practical use.

Hierarchical porous carbon foam embedded with readily accessible atomic iron sites for efficient electrochemical nitrite sensing

A hierarchical porous carbon foam embedded with atomic iron sites is facilely synthesized and works as an efficient electrochemical nitrite sensor.

Bidirectional Atomic Iron Catalysis of Sulfur Redox Conversion in High‐Energy Flexible ZnS Battery

AbstractTo achieve the full theoretical potential of high energy ZnS electrochemistry, the incomplete and sluggish conversion during battery discharging and high reactivation energy barrier during battery recharging associated with the sulfur cathodes must be overcome. Herein, the atomically dispersed Fe sites with FeN4 coordination are experimentally and theoretically predicted as bidirectional electrocatalytic hotspots to simultaneously manipulate the complete sulfur conversion and minimize the energy barrier of ZnS decomposition. It is discovered that the Fe sites were favorable for strong sulfur and possible zinc polysulfide intermediate adsorption, and ensure nearly complete sulfur to ZnS conversion during discharge. For the following recharging process, the electrodeposited ZnS can be readily reversible charged back to S without a noticeable activation overpotential around FeN4 moieties comparing to pure carbon matrixes. As expected, the freestanding iron embedded carbon fiber cloth supported sulfur cathode delivers a high specific capacity of 1143 mAh g−1 and a lower voltage hysteresis of 0.61 V. As elaborated by postmortem analysis, the degradation mechanism of ZnS cell is the accumulation of inactive ZnS crystals on the cathode side rather than the Zn metallic depletion. More encouragingly, a flexible solid‐state ZnS battery with a high discharge capacity and stable reversibility is also demonstrated.

N, Si-codoped carbon-based iron catalyst for efficient, selective synthesis of pyrroles from nitroarenes: The role of Si doping

The development of novel iron heterogeneous catalysts for organic synthesis is attractive and significant for both academic and industrial applications. A carbon-based iron heterogeneous catalyst (Fe@NSiC) comprising of different iron species including iron atomic single sites (FeNxSiy), iron silicate and iron nanoparticles (NPs) has been developed. This catalyst exhibits high performance on the solvent-free synthesis of pyrroles from nitroarenes and 2,5-hexanedione via cascade reaction using HCOOH/DBU as the reductant. Si doping can increase Lewis acid sites of the catalyst and the electron density of iron sites, thus promoting the reaction. Furthermore, a set of pyrroles reflecting potential interest from the pharmaceutical perspective are obtained with moderate to excellent yields in this chemistry.

(Invited, Digital Presentation) Methane Conversion to High Value Chemicals By Photocatalysis

As underlined in the COP26, methane as a greenhouse gas is nearly 80 time more potent than CO2 while its reserve is much more than the sum of coal, oil and natural gas. Thus methane conversion not only involves the environmental issue but also is related to high-value chemical production /clean energy supply, which has been attracting substantial interest over the last decades. However CH4 activation is energy intensive and kinetically very challenging so that methane activation is regarded as the “holy grail” in the catalytically chemical process. [1] Photocatalysis provides a cost efficient potential to activation of such small molecule under very mild conditions, while to achieve the potential is a huge challenge.[2]Stimulated by our research outcomes on the charge dynamics in inorganic semiconductor photocatalysis, which reveal that the low reaction efficiency is due to both fast charge recombination and large bandgap of an inorganic semiconductor [3,4], together with the recent findings on atomic catalysis [5], we developed novel material strategies for photocatalytic methane conversion to methanol. Highly dispersed atomic level iron species immobilised on a TiO2 photocatalyst show an excellent activity for methane conversion, resulting into ~97% selectivity towards alcohols operated under ambient conditions by a one-step chemical process [6]. Such photocatalyst is also very stable, promising an attractive industrial process of methane upgrade. The dominating function of the iron species has also been investigated in detail. Furthermore, we designed a flow system for relatively efficient methane to C2, achieving the benchmark results in this area.[7] In addition, C1 oxygenates can be produced with nearly 100% by photocatalytic methane conversion due to the synergy between Au and Cu cocatalysts loaded on ZnO.[8] References ： Li, X. Wang, C., Tang, J. Nature Reviews Materials , 2022, Doi: 1038/s41578-022-00422-3.Wang Y., Suzuki H., Xie, J., Tomita, O., Martin, D. J., Higashi, M., Kong, D., Abe R. Tang, J., Chem. Rev., 2018, 118: 5201-5241.Tang, J. Durrant J. R., Klug, R ., J. Am. Chem. Soc ., 2008, 130(42) : 13885-13891.Miao, T., Wang, C., Xiong, L., Li, X., Xie, X., Tang, J., ACS Catalysis , 2021, 11, 8226-8238.Wang, A. Li J., Zhang. T., Nat . Rev. Chem ., 2018, 2; 65-81.Xie, J., Jin, R. ,Li, A., Bi, Y., Sankar, G. , Ma , Tang, J. Nature Catalysis , 2018, 1: 889-896.Li, X., Xie J.,Rao, H., Wang, , Tang, J., Angewandte Chemie International Edition , 2020, 132: 19870-19875.Luo, L., Gong, Z., Xu, Y., Ma, J., Liu, H., Xing, J., Tang, J., Journal of the American Chemical Society , 2022, 144, 2, 740–750.

An extraordinary Na-S battery enabled by a carbon nanosheet host loaded with Fe-accelerator and TiO2-inhibitor

The inexpensive room-temperature sodium-sulfur (RT Na-S) battery has attracted extensive attention due to its various potential application but is still suffering from the low utilization of sulfur, the shuttle effect and the sluggish reaction activity of sodium polysulfides (SPSs). In this work, a TiO2/sulfur/atomic-iron loaded carbon nanosheet cathode is designed for high performance RT Na-S battery. When the atomic iron exists, a much higher electrochemical activity of sulfur was obtained, indicating the atomic iron can accelerate the conversion of SPSs. Furthermore, the TiO2 layer can inhibit the shuttle effect of SPSs and the side-reaction between the intermediates and carbonate electrolyte. As a result, the constructed sulfur cathode exhibits a high reversible capacity (569.9 mAh g−1 with an initial coulombic efficiency of 57.57%) at 0.1 A g−1 and outstanding cycling performance (507 mAh g−1 after 50 cycles). This work provides a new strategy for preparing high performance cathode materials for RT Na-S battery.