Coexistence of Fe Nanoclusters Boosting Fe Single Atoms to Generate Singlet Oxygen for Efficient Aerobic Oxidation of Primary Amines to Imines

Electron Reservoir Effect of Adjacent Fe Nanoclusters Boosts Atomic Fe Active Sites on Porous Carbon for the Both Electrocatalytic Oxygen Reduction and CO2 Reduction Reaction

Electrochemical oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO2RR) are greatly significant in renewable energy-related devices and carbon-neutral closed cycle, while the development of robust and highly efficient electrocatalysts has remained challenges. Herein, a hybrid electrocatalyst, featuring axial N-coordinated Fe single atom sites on hierarchically N, P-codoped porous carbon support and Fe nanoclusters as electron reservoir (FeNCs/FeSAs-NPC), is fabricated via in situ thermal transformation of the precursor of a supramolecular polymer initiated by intermolecular hydrogen bonds co-assembly. The FeNCs/FeSAs-NPC catalyst manifests superior oxygen reduction activity with a half-wave potential of 0.91 V in alkaline solution, as well as high CO2 to CO Faraday efficiency (FE) of surpassing 90% in a wide potential window from -0.40 to -0.85 V, along with excellent electrochemical durability. Theoretical calculations indicate that the electron reservoir effect of Fe nanoclusters can trigger the electron redistribution of the atomic Fe moieties, facilitating the activation of O2 and CO2 molecules, lowering the energy barriers for rate-determining step, and thus contributing to the accelerated ORR and CO2RR kinetics. This work offers an effective design of electron coupling catalysts that have advanced single atoms coexisting with nanoclusters for efficient ORR and CO2RR.

Asymmetrically Coordinated Mn-S1N3 Configuration Induces Localized Electric Field-Driven Peroxymonosulfate Activation for Remarkably Efficient Generation of 1O2

Singlet oxygen (1O2) species generated in peroxymonosulfate (PMS)-based advanced oxidation processes offer opportunities to overcome the low efficiency and secondary pollution limitations of existing AOPs, but efficient production of 1O2 via tuning the coordination environment of metal active sites remains challenging due to insufficient understanding of their catalytic mechanisms. Herein, an asymmetrical configuration characterized by a manganese single atom coordinated is established with one S atom and three N atoms (denoted as Mn-S1N3), which offer a strong local electric field to promote the cleavage of O─H and S─O bonds, serving as the crucial driver of its high 1O2 production. Strikingly, an enhanced the local electric field caused by the dynamic inter-transformation of the Mn coordination structure (Mn-S1N3 ↔ Mn-N3) can further downshift the 1O2 production energy barrier. Mn-S1N3 demonstrates 100% selective product 1O2 by activation of PMS at unprecedented utilization efficiency, and efficiently oxidize electron-rich pollutants. This work provides an atomic-level understanding of the catalytic selectivity and is expected to guide the design of smart 1O2-AOPs catalysts for more selective and efficient decontamination applications.

Advances of Synergistic Electrocatalysis Between Single Atoms and Nanoparticles/Clusters

Combining single atoms with clusters or nanoparticles is an emerging tactic to design efficient electrocatalysts. Both synergy effect and high atomic utilization of active sites in the composite catalysts result in enhanced electrocatalytic performance, simultaneously provide a radical analysis of the interrelationship between structure and activity. In this review, the recent advances of single-atomic site catalysts coupled with clusters or nanoparticles are emphasized. Firstly, the synthetic strategies, characterization, dynamics and types of single atoms coupled with clusters/nanoparticles are introduced, and then the key factors controlling the structure of the composite catalysts are discussed. Next, several clean energy catalytic reactions performed over the synergistic composite catalysts are illustrated. Eventually, the encountering challenges and recommendations for the future advancement of synergistic structure in energy-transformation electrocatalysis are outlined.

Single-Atom palladium engineered cobalt nanocomposite for selective aerobic oxidation of sulfides to sulfoxides

Developing efficient catalysts for the selective oxidation of sulfides to sulfoxides using molecular oxygen as the oxidant is a challenging task. Here, we report a novel catalyst comprising a single atom palladium engineered cobalt nanocomposite (denoted as PdCo@NC-800-0.01) for this reaction. The incorporation of single atom palladium effectively transforms an originally inactive cobalt nanocomposite into a highly efficient and selective catalyst for the oxidation of sulfides. This catalyst PdCo@NC-800-0.01 exhibited outstanding performance in the selective oxidation of sulfides to sulfoxides using O2 as the oxidant in the presence of isobutyraldehyde (IBA) under mild conditions, demonstrating high activity and excellent selectivity for a broad spectrum of sulfides with good tolerance toward various functional groups, including those susceptible to oxidation. Furthermore, the catalyst could be easily recovered and reused up to 10 times without any significant loss in activity and selectivity. Comprehensive characterizations and theoretical calculations revealed that the engineering of cobalt nanocomposite with single atom Pd greatly enhanced the ability to adsorb and activate IBA, leading to the generation of the key acyl radical. This radical then reacted with singlet oxygen 1O2 derived from molecular oxygen, producing reactive oxygen species peroxy radical, which ultimately promoted the catalytic performance.

Iron Monomers or Trimers on Nitrogen-Doped Carbon: Which Is Better for the Electrocatalytic Nitrogen Reduction Reaction?

The electrocatalytic nitrogen reduction reaction (NRR) presents an alternative method for the Haber-Bosch process, and single-atom catalysts (SACs) to achieve efficient NRR have attracted considerable attention in the past decades. However, whether SACs are more suitable for NRR compared to atomic-cluster catalysts (ACCs) remains to be studied. Herein, we have successfully synthesized both the Fe monomers (Fe1) and trimers (Fe3) on nitrogen-doped carbon catalysts. Both the experiments and DFT calculations indicate that compared to the end-on adsorption of N2 on Fe1 catalysts, N2 activation is enhanced via the side-on adsorption on Fe3 catalysts, and the reaction follows the enzymatic pathway with a reduced free energy barrier for NRR. As a result, the Fe3 catalysts achieved better NRR performance (NH3 yield rate of 27.89 μg h-1 mg-1cat. and Faradaic efficiency of 45.13%) than Fe1 catalysts (10.98 μg h-1 mg-1cat. and 20.98%). Therefore, our research presents guidance to prepare more efficient NRR catalysts.

Ball-milled prepared Fe3O4-FeSAs-NPs@NC catalyst synergistically facilitate the generation of reactive oxygen species for oxidative trifluoromethylation of alkenes

Heterogeneous catalysts have recently regarded as a promising chose for the thermally-driven generation of the reactive oxygen species (ROS) through catalytic reactions with molecular oxygen, which can facilitate this process by specific geometric and electronic structure. However, the oxidative trifluoromethylation of alkenes to α-trifluoromethylated ketones by CF3SO2Na is rarely reported in this system. In this work, we report a one-pot polymerization ball milling strategy to construct precursor, and then pyrolyze it to obtain specific carbon nanotubes matrix with Fe/Fe3O4 nanoparticles and single atoms Fe. Remarkably, the optimized catalyst (Fe3O4-FeSAs-NPs@NC-1) displays excellent catalytic performance, broad substrates and recyclability for this fluorination reaction via radical pathway. Based on characterizations and mechanistic studies, we discover that the coexistence of Fe/Fe3O4 and Fe-Nx not only synergistically facilitates the catalytic efficiency in altering the electronic structure of Fe sites, but also benefits the absorption of O2 and the ability of the thermally-driven generating ROS which can activate CF3SO2Na to CF3 radical. This work offers a method of designing Fe-based catalysts and also opens up a new thermal-heterogeneous catalysis way for the oxidative trifluoromethylation of alkenes.

De Novo Synthesis of Acridone-Based Zn-Metal-Organic Framework (Zn-MOF) as a Photocatalyst: Application for Visible Light-Mediated Oxidation of Sulfides and Enaminones

Acridone, a cyclic analogue of benzophenone that undergoes efficient intersystem crossing (ISC) to the triplet-excited state with near-unity quantum yield, was elaborated as a 3-connecting triacid linker, i.e., H3AcTA, to develop a photocatalytic metal-organic framework (MOF) for energy transfer applications; the triacid linker inherently features concave shapes, an attribute that is important for the construction of MOFs with significant porosity. Metal ion (Zn2+)-assisted self-assembly of the triacid yielded a Zn-MOF, i.e., Zn-AcTA, with a solvent-accessible volume of ca. 31%. The protection of the acridone chromophore in the MOF in conjunction with a wider cross-section of its absorption in the visible region renders the MOF an excellent heterogeneous photosensitizer for singlet oxygen (1O2) generation by energy transfer to the ground-state triplet oxygen (3O2). It is shown that the Zn-MOF can be applied as a photosensitizing catalyst for visible light-mediated oxidation of various sulfides to sulfoxides and enaminones to amino-esters via 1,2-acyl migration. It is further demonstrated that the photocatalyst can be easily recycled without any loss of catalytic activity and structural integrity. Based on mechanistic investigations, 1O2 is established as the reactive oxygen species in photocatalytic oxidation reactions. The results constitute the first demonstration of rational development of a photocatalytic MOF based on acridone for heterogeneous oxidations mediated by 1O2.

Nanoscale Metal Particle Modified Single-Atom Catalyst: Synthesis, Characterization, and Application

Single-atom catalysts (SACs) have attracted considerable attention in heterogeneous catalysis because of their well-defined active sites, maximum atomic utilization efficiency, and unique unsaturated coordinated structures. However, their effectiveness is limited to reactions requiring active sites containing multiple metal atoms. Furthermore, the loading amounts of single-atom sites must be restricted to prevent aggregation, which can adversely affect the catalytic performance despite the high activity of the individual atoms. The introduction of nanoscale metal particles (NMPs) into SACs (NMP-SACs) has proven to be an efficient approach for improving their catalytic performance. A comprehensive review is urgently needed to systematically introduce the synthesis, characterization, and application of NMP-SACs and the mechanisms behind their superior catalytic performance. This review first presents and classifies the different mechanisms through which NMPs enhance the performance of SACs. It then summarizes the currently reported synthetic strategies and state-of-the-art characterization techniques of NMP-SACs. Moreover, their application in electro/thermo/photocatalysis, and the reasons for their superior performance are discussed. Finally, the challenges and perspectives of NMP-SACs for the future design of advanced catalysts are addressed.

Single atom catalyst-mediated generation of reactive species in water treatment

Water is one of the most essential components in the sustainable development goals (SDGs) of the United Nations. With worsening global water scarcity, especially in some developing countries, water reuse is gaining increasing acceptance. A key challenge in water treatment by conventional treatment processes is the difficulty of treating low concentrations of pollutants (micromolar to nanomolar) in the presence of much higher levels of inorganic ions and natural organic matter (NOM) in water (or real water matrices). Advanced oxidation processes (AOPs) have emerged as an attractive treatment technology that generates reactive species with high redox potentials (E0) (e.g., hydroxyl radical (HO˙), singlet oxygen (1O2), sulfate radical (SO4˙-), and high-valent metals like iron(IV) (Fe(IV)), copper(III) (Cu(III)), and cobalt(IV) (Co(IV))). The use of single atom catalysts (SACs) in AOPs and water treatment technologies has appeared only recently. This review introduces the application of SACs in the activation of hydrogen peroxide and persulfate to produce reactive species in treatment processes. A significant part of the review is devoted to the mechanistic aspects of traditional AOPs and their comparison with those triggered by SACs. The radical species, SO4˙- and HO˙, which are produced in both traditional and SACs-activated AOPs, have higher redox potentials than non-radical species, 1O2 and high-valent metal species. However, SO4˙- and HO˙ radicals are non-selective and easily affected by components of water while non-radicals resist the impact of such constituents in water. Significantly, SACs with varying coordination environments and structures can be tuned to exclusively generate non-radical species to treat water with a complex matrix. Almost no influence of chloride, carbonate, phosphate, and NOM was observed on the performance of SACs in treating pollutants in water when nonradical species dominate. Therefore, the appropriately designed SACs represent game-changers in purifying water vs. AOPs with high efficiency and minimal interference from constituents of polluted water to meet the goals of water sustainability.

Electric Field Enhanced Ammoxidation of Aldehydes Using Supported Fe Clusters Under Ambient Oxygen Pressure

Heterogeneous catalytic ammoxidation provides an eco-friendly route for the cyanide-free synthesis of nitrile compounds, which are important precursors for synthetic chemistry and pharmaceutical applications. However, in general such a process requires high pressures of molecular oxygen at elevated temperatures to accelerate the oxygen reduction and imine dehydrogenation steps, which is highly risky in practical applications. Here, we report an electric field enhanced ammoxidation system using a supported Fe clusters catalyst (Fe/NC), which enables efficient synthesis of nitriles from the corresponding aldehydes under ambient air pressure at room temperature (RT). A synergistic effect between the external electric field and the Fe/NC catalyst promotes the ammonia activation and the dehydrogenation of the generated imine intermediates and avoids the unwanted backwards reaction to aldehydes. This electric field enhanced ammoxidation system presents high efficiency and selectivity for the conversion of a series of aldehydes under mild conditions with high durability, rendering it an attractive process for the green synthesis of nitriles with fragile functional groups.

Ce4+/Ce3+ Redox Effect-Promoted CdS/CeO2 Heterojunction Photocatalyst for the Atom Economic Synthesis of Imines under Visible Light

The employment of stoichiometric alcohols and amines for imine synthesis under mild and green reaction conditions is still a challenge in the field. In this work, based on our research foundation in the thermocatalytic synthesis of imines over ceria, a CdS/CeO2 heterojunction photocatalyst was constructed and successfully realized the atom-economic synthesis of imines under visible light without additives at room temperature. Mechanistic experiments and corresponding characterizations indicated that the CdS/CeO2 heterojunction can improve the separation efficiency of photogenerated carriers, which can be further enhanced by the Ce4+/Ce3+ redox pair by rapidly combining photogenerated e-. The in situ-reduced Ce3+ can better activate O2 to form Ce-O-O·, which, together with h+, efficiently accelerates alcohol oxidation, which is the rate-determined step for the synthesis of imines via oxidative coupling reaction of alcohol and amine. In addition, our photocatalyst exhibited fairly decent reusability and substrate universality. This work solves problems of using base additives and excess amine or alcohol in the reported photocatalytic systems and provides new insight for designing CeO2-based photocatalytic oxidation catalysts.

Single-atom catalysts-based catalytic ROS clearance for efficient psoriasis treatment and relapse prevention via restoring ESR1

Psoriasis is a common inflammatory disease of especially high recurrence rate (90%) which is suffered by approximately 3% of the world population. The overexpression of reactive oxygen species (ROS) plays a critical role in psoriasis progress. Here we show that biomimetic iron single-atom catalysts (FeN4O2-SACs) with broad-spectrum ROS scavenging capability can be used for psoriasis treatment and relapse prevention via related gene restoration. FeN4O2-SACs demonstrate attractive multiple enzyme-mimicking activities based on atomically dispersed Fe active structures, which are analogous to those of natural antioxidant enzymes, iron superoxide dismutase, human erythrocyte catalase, and ascorbate peroxidase. Further, in vitro and in vivo experiments show that FeN4O2-SACs can effectively ameliorate psoriasis-like symptoms and prevent the relapse with augmented efficacy compared with the clinical drug calcipotriol. Mechanistically, estrogen receptor 1 (ESR1) is identified as the core protein upregulated in psoriasis treatment through RNA sequencing and bioinformatic analysis. Together, this study provides a proof of concept of psoriasis catalytic therapy (PCT) and multienzyme-inspired bionics (MIB).

Water-Promoted Carbon-Carbon Bond Cleavage Employing a Reusable Fe Single-Atom Catalyst

The development of methods for selective cleavage reactions of thermodynamically stable C-C/C=C bonds in a green manner is a challenging research field which is largely unexplored. Herein, we present a heterogeneous Fe-N-C catalyst with highly dispersed iron centers that allows for the oxidative C-C/C=C bond cleavage of amines, secondary alcohols, ketones, and olefins in the presence of air (O2 ) and water (H2 O). Mechanistic studies reveal the presence of water to be essential for the performance of the Fe-N-C system, boosting the product yield from <1 % to >90 %. Combined spectroscopic characterizations and control experiments suggest the singlet 1 O2 and hydroxide species generated from O2 and H2 O, respectively, take selectively part in the C-C bond cleavage. The broad applicability (>40 examples) even for complex drugs as well as high activity, selectivity, and durability under comparably mild conditions highlight this unique catalytic system.

Preparation of mesoporous chitosan iron supported nano-catalyst for the catalyzed oxidation of primary amine to imine

Supported nano-catalysts with environmental sustainability and high catalytic performance are of great research interest for sustainable catalysis. In this article, a supported nano-catalyst, FeA-NC, with high catalytic performance was prepared by anchoring the transition metal iron onto nitrogen-doped porous carbon materials using chitosan as a raw material. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) measurement results demonstrated that the obtained catalyst has an excellent mesoporous structure, and that the element Fe is evenly distributed. The support contains abundant N atoms, which can provide sufficient anchoring points for Fe and form Fe-Nx groups with Fe, improving the catalytic activity of the catalyst. Additionally, the FeA-NC with a porous structure can also enhance the mass transfer of reactants to improve the reaction efficiency. In addition, the prepared catalyst was used to catalyze the conversion of primary amines to the corresponding imines. The results showed that the direct oxidation of primary amines to the corresponding imines can be catalyzed by using air as an oxygen source and distilled H2O as a solvent under atmospheric pressure at 90 °C. Finally, the selectivity and stability of the as-prepared catalyst were also verified.

Dual-Active-Sites Single-Atom Catalysts for Advanced Applications

Dual-Active-Sites Single-Atom catalysts (DASs SACs) are not only the improvement of SACs but also the expansion of dual-atom catalysts. The DASs SACs contains dual active sites, one of which is a single atomic active site, and the other active site can be a single atom or other type of active site, endowing DASs SACs with excellent catalytic performance and a wide range of applications. The DASs SACs are categorized into seven types, including the neighboring mono metallic DASs SACs, bonded DASs SACs, non-bonded DASs SACs, bridged DASs SACs, asymmetric DASs SACs, metal and nonmetal combined DASs SACs and space separated DASs SACs. Based on the above classification, the general methods for the preparation of DASs SACs are comprehensively described, especially their structural characteristics are discussed in detail. Meanwhile, the in-depth assessments of DASs SACs for variety applications including electrocatalysis, thermocatalysis and photocatalysis are provided, as well as their unique catalytic mechanism are addressed. Moreover, the prospects and challenges for DASs SACs and related applications are highlighted. The authors believe the great expectations for DASs SACs, and this review will provide novel conceptual and methodological perspectives and exciting opportunities for further development and application of DASs SACs.

Identification of Dynamic Active Sites Among Cu Species Derived from MOFs@CuPc for Electrocatalytic Nitrate Reduction Reaction to Ammonia

Direct electrochemical nitrate reduction reaction (NITRR) is a promising strategy to alleviate the unbalanced nitrogen cycle while achieving the electrosynthesis of ammonia. However, the restructuration of the high-activity Cu-based electrocatalysts in the NITRR process has hindered the identification of dynamical active sites and in-depth investigation of the catalytic mechanism. Herein, Cu species (single-atom, clusters, and nanoparticles) with tunable loading supported on N-doped TiO2/C are successfully manufactured with MOFs@CuPc precursors via the pre-anchor and post-pyrolysis strategy. Restructuration behavior among Cu species is co-dependent on the Cu loading and reaction potential, as evidenced by the advanced operando X-ray absorption spectroscopy, and there exists an incompletely reversible transformation of the restructured structure to the initial state. Notably, restructured CuN4&Cu4 deliver the high NH3 yield of 88.2 mmol h-1 gcata-1 and FE (~ 94.3%) at - 0.75 V, resulting from the optimal adsorption of NO3- as well as the rapid conversion of *NH2OH to *NH2 intermediates originated from the modulation of charge distribution and d-band center for Cu site. This work not only uncovers CuN4&Cu4 have the promising NITRR but also identifies the dynamic Cu species active sites that play a critical role in the efficient electrocatalytic reduction in nitrate to ammonia.

Remote Synergy between Heterogeneous Single Atoms and Clusters for Enhanced Oxygen Evolution

Integrating single atoms and clusters into one system is a novel strategy to achieve desired catalytic performances. Compared with homogeneous single-atom cluster catalysts, heterogeneous ones combine the merits of different species and therefore show greater potential. However, it is still challenging to construct single-atom cluster systems of heterogeneous species, and the underlying mechanism for activity improvement remains unclear. In this work, we developed a heterogeneous single-atom cluster catalyst (Co_nIr₁/N-C) for efficient oxygen evolution. The Ir single atoms worked in synergy with the Co clusters at a distance of about 8 Å, which optimized the configuration of the key intermediates. Consequently, the oxygen evolution activity was significantly improved on Co_nIr₁/N-C relative to the Co cluster catalyst (Co_n/N-C), exhibiting an overpotential lower by 107 mV than that of Co_n/N-C at 10 mA cm^-2 and a turnover frequency 50.9 times as much as that of Co_n/N-C at an overpotential of 300 mV.

Direct Observation of Transition Metal Ions Evolving into Single Atoms: Formation and Transformation of Nanoparticle Intermediates

Understanding the dynamical evolution from metal ions to single atoms is of great importance to the rational development of synthesis strategies for single atom catalysts (SACs) against metal sintering during pyrolysis. Herein, an in situ observation is disclosed that the formation of SACs is ascertained as a two-step process. There is initially metal sintering into nanoparticles (NPs) (500-600 °C), followed by the conversion of NPs into metal single atoms (Fe, Co, Ni, Cu SAs) at higher temperature (700-800 °C). Theoretical calculations together with control experiments based on Cu unveil that the ion-to-NP conversion can arise from the carbon reduction, and NP-to-SA conversion being steered by generating more thermodynamically stable Cu-N₄ configuration instead of Cu NPs. Based on the evidenced mechanism, a two-step pyrolysis strategy to access Cu SACs is developed, which exhibits excellent ORR performance.

Biomass-Derived Single Zn Atom Catalysts: The Multiple Roles of Single Zn Atoms in the Oxidative Cleavage of C-N Bonds

The C-N bond cleavage represents one kind of important organic and biochemical transformation, which has attracted great interest in recent years. The oxidative cleavage of C-N bonds in N,N-dialkylamines into N-alkylamines has been well documented, but it is challenging in the further oxidative cleavage of C-N bonds in N-alkylamines into primary amines due to the thermally unfavorable release of α-position H from N-C_α-H and the paralleling side reactions. Herein, a biomass-derived single Zn atom catalyst (ZnN₄-SAC) was discovered to be a robust heterogeneous non-noble catalyst for the oxidative cleavage of C-N bonds in N-alkylamines with O₂ molecules. Experimental results and DFT calculation revealed that ZnN₄-SAC not only activates O₂ to generate superoxide radicals (·O₂ ^-) for the oxidation of N-alkylamines to generate imine intermediates (C=N), but the single Zn atoms also served as the Lewis acid sites to promote the cleavage of C=N bonds in imine intermediates, including the first addition of H₂O to generate α-hydroxylamine intermediates and the following C-N bond cleavage via a H atom transfer process.

Cobalt catalysts (Co–N–C) for C–O bond cleavage in lignin-derived aryl ethers and lignin

The transformation of lignin into value-added chemicals represents one of the relevant approaches for sustainable development.

MOF-Derived Co and Fe Species Loaded on N-Doped Carbon Networks as Efficient Oxygen Electrocatalysts for Zn-Air Batteries

HIGHLIGHTS

A novel method is developed to prepare bifunctional oxygen electrocatalysts composed of Co nanoparticles and highly dispersed Fe loaded on N-doped carbon substrates by virtues of metal-organic frameworks and two different doping processes. The designed catalysts show comparable performance with commercial catalysts. Meanwhile, rechargeable Zn-air batteries with prepared catalysts demonstrate high peak power density and good cycling stability. The performance promotion originates from the synergy between Co nanoparticles and highly dispersed Fe, porous structures, large specific areas, and distinct three-dimensional carbon networks.  .

ABSTRACT

Searching for cheap, efficient, and stable oxygen electrocatalysts is vital to promote the practical performance of Zn-air batteries with high theoretic energy density. Herein, a series of Co nanoparticles and highly dispersed Fe loaded on N-doped porous carbon substrates are prepared through a “double-solvent” method with in situ doped metal-organic frameworks as precursors. The optimized catalysts exhibit excellent performance for oxygen reduction and evolution reaction. Furthermore, rechargeable Zn-air batteries with designed catalysts demonstrate higher peak power density and better cycling stability than those with commercial Pt/C+RuO₂. According to structure characterizations and electrochemical tests, the interaction of Co nanoparticles and highly dispersed Fe contributes to the superior performance for oxygen electrocatalysis. In addition, large specific surface areas, porous structures and interconnected three-dimensional carbon networks also play important roles in improving oxygen electrocatalysis. This work provides inspiration for rational design of advanced oxygen electrocatalysts and paves a way for the practical application of rechargeable Zn-air batteries. [Image: see text]

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40820-022-00890-w.