Single Atom Research Articles

Single-Atom Pt Loaded on MOF-Derived Porous TiO2 with Maxim-Ized Pt Atom Utilization for Selective Hydrogenation of Halonitro-benzene.

The location control of single atoms relative to supports is challenging for single-atom catalysts, leading to a large proportion of inaccessible single atoms buried under supports. Herein, a "sequential thermal transition" strategy is developed to afford single-atom Pt preferentially dispersed on the outer surface of TiO2. Specifically, a Ti-MOF confining Pt nanoparticles is converted to PtNPs and TiO2 composite coated by carbon (PtNPs&TiO2@C-800) at 800 °C in N2. Subsequent thermal-driven atomization of PtNPs at 600 °C in air produce single-atom Pt decorated TiO2 (Pt1/TiO2-600). The resulting Pt1/TiO2-600 exhibits superior p-chloroaniline (p-CAN) selectivity (99 %) to PtNPs/TiO2-400 (45 %) and much better activity than Pt1@TiO2-600 with randomly dispersed Pt1 both outside and inside TiO2 in the hydrogenation of p-chloronitrobenzene (p-CNB). Mechanism investigations reveal that Pt1/TiO2-600 achieves 100 % accessibility of Pt1 and preferably adsorbs the -NO2 group of p-CNB while weakly adsorbs -Cl group of p-CNB and p-CAN, promoting catalytic activity and selectivity.

Single‐Atom Pt Loaded on MOF‐Derived Porous TiO2 with Maxim‐Ized Pt Atom Utilization for Selective Hydrogenation of Halonitro‐benzene

AbstractThe location control of single atoms relative to supports is challenging for single‐atom catalysts, leading to a large proportion of inaccessible single atoms buried under supports. Herein, a “sequential thermal transition” strategy is developed to afford single‐atom Pt preferentially dispersed on the outer surface of TiO2. Specifically, a Ti‐MOF confining Pt nanoparticles is converted to PtNPs and TiO2 composite coated by carbon (PtNPs&TiO2@C‐800) at 800 °C in N2. Subsequent thermal‐driven atomization of PtNPs at 600 °C in air produce single‐atom Pt decorated TiO2 (Pt1/TiO2‐600). The resulting Pt1/TiO2‐600 exhibits superior p‐chloroaniline (p‐CAN) selectivity (99 %) to PtNPs/TiO2‐400 (45 %) and much better activity than Pt1@TiO2‐600 with randomly dispersed Pt1 both outside and inside TiO2 in the hydrogenation of p‐chloronitrobenzene (p‐CNB). Mechanism investigations reveal that Pt1/TiO2‐600 achieves 100 % accessibility of Pt1 and preferably adsorbs the –NO2 group of p‐CNB while weakly adsorbs –Cl group of p‐CNB and p‐CAN, promoting catalytic activity and selectivity.

Asymmetric Charge Distribution in Atomically Precise Metal Nanoclusters for Boosted CO2 Reduction Catalysis.

Recently, atomically precise metal nanoclusters (NCs) have been widely applied in CO2 reduction reaction (CO2RR), achieving exciting activity and selectivity and revealing structure-performance correlation. However, at present, the efficiency of CO2RR is still unsatisfactory and cannot meet the requirements of practical applications. One of the main reasons is the difficulty in CO2 activation due to the chemical inertness of CO2. Constructing symmetry-breaking active sites is regarded as an effective strategy to promote CO2 activation by modulating electronic and geometric structure of CO2 molecule. In addition, in the subsequent CO2RR process, asymmetric charge distributed sites can break the charge balance in adjacent adsorbed C1 intermediates and suppress electrostatic repulsion between dipoles, benefiting for C-C coupling to generate C2+ products. Although compared to single atoms, metal nanoparticles, and inorganic materials the research on the construction of asymmetric catalytic sites in metal NCs is in a newly-developing stage, the precision, adjustability and diversity of metal NCs structure provide many possibilities to build asymmetric sites. This review summarizes several strategies of construction asymmetric charge distribution in metal NCs for boosting CO2RR, concludes the mechanism investigation paradigm of NCs-based catalysts, and proposes the challenges and opportunities of NCs catalysis.

Theoretical Study on Pt1/CeO2 Single Atom Catalysts for CO Oxidation

Understanding the influence of structural configurations on catalytic performance is crucial for optimizing atom‐efficient single‐atom catalysts (SACs). In this study, we conducted a density functional theory (DFT) investigation of single Pt atoms positioned at step‐edges and within a solid solution on the CeO2(111) surface. We compared these configurations in terms of thermodynamic stability, electronic properties, and further potential energy surfaces for CO oxidation. Stability studies revealed that the solid solution catalyst exhibits greater stability compared to the step‐edge catalyst. Additionally, the Pt in the solid solution catalyst can effectively activate lattice oxygen atoms, making the catalyst more conducive to the formation of oxygen vacancies. The CO oxidation process was analyzed using the Mars‐van Krevelen mechanism, revealing that the solid solution catalyst possesses a more moderate CO adsorption energy. This, coupled with its lower oxygen vacancy formation energy, leads to reduced energy barriers throughout the CO oxidation cycle. Our findings highlight the strong dependence of catalytic activity on the specific configuration of Pt atoms within the CeO2 matrix, with the solid solution model demonstrating superior catalytic efficiency compared to the step‐edge‐supported Pt catalysts.

Atomically Tailored Zn-ZIF-8 via RuNi Nanoalloy Replacement for Improved Photocatalytic H2 Evolution.

In this study, we developed a solid-state atomic replacement method for metal catalysts, enabling the exchange of metal atoms between single atoms and nanoalloys to create new combinations of nanoalloys and single atoms. We observed that partial metal interchange occurred between the RuNi nanoalloy and Zn from the zeolitic imidazolate framework-8 (ZIF-8) on a carbon-nitrogen framework (CNF) at a high temperature of 900 °C, leading to the creation of RuZn nanoparticles and single nickel atoms (Ni-CN). Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) analyses revealed that Ni is atomically dispersed within (RuZn)/Ni-CN. This finding confirms the migration of Zn and Ni during the pyrolysis of the RuNi@ZIF-8 precursor, providing definitive evidence of atomic replacement. Due to the synergistic influence of RuZn nanocrystals and Ni-CN, the resulting (RuZn)/Ni-CN multisite catalyst exhibited superior hydrogen evolution reaction (HER) ability compared to the conventional nanoalloy-based catalysts. Density functional theory calculations revealed that the integration of the (RuZn)n cluster on Ni surrounded with different N-coordinated carbon structures enhanced HER activity with the optimized (RuZn)n/NiN2C2 catalyst exhibiting a low ΔGH and improved electron charge redistribution, thereby promoting favorable hydrogen adsorption. Our findings provide valuable insights into the design and optimization of photocatalysts through atomic-level engineering, opening new avenues for efficient and sustainable energy conversion technologies.

Fe‐N‐C in Proton Exchange Membrane Fuel Cells: Impact of Ionomer Loading on Degradation and Stability

AbstractFe single atoms in N‐doped C (Fe‐N‐C) present the most promising replacement for carbon‐supported Pt‐based catalysts for the O2 reduction reaction at the cathode of proton exchange membrane fuel cells (PEMFCs). However, it remains unclear how the I/C ratio affects Fe‐N‐C degradation and the stability of single Fe atom active sites (FeNx). Here, an accelerated stress test (AST) protocol is combined with emerging electrochemical techniques for a porous Fe‐N‐C in PEMFC with a range of I/C ratios. The PEMFC current density degradation rates are found to be comparable; however, with increased I/C ratio the additional FeNx sites accessed are more stable, as shown by their higher active site stability number (electrons passed per FeNx lost) at the end of the AST protocol. Meanwhile, the initial rate of TOF decay is suppressed with increasing I/C. Electrochemical process changes are studied via distribution of relaxation times analysis. Minor changes in H+ and O2 transport resistance at low current density prove kinetic degradation dominants at high potentials. These findings demonstrate how electrochemical techniques can be combined with stability metrics to determine and deconvolute changes from the active site to device level electrochemical processes in PEMFCs.

Investigation of the mechanism of [M-H]+ ion formation in photoionized N-alkyl-substituted thieno[3,4-c]-pyrrole-4,6-dione derivatives during higher order MSn high-resolution mass spectrometry.

The mechanism underlying dopant-assisted atmospheric pressure photoionization's (APPI) formation of ions is unclear and still under debate for many chemical classes. In this study, we reexamined the gas-phase reaction mechanisms responsible for the generation of [M-H]+ precursor ions, resulting from the loss of a single hydrogen atom, in a series of N-alkyl-substituted thieno[3,4-c]-pyrrole-4,6-dione (TPD) derivatives. Atmospheric pressure photoionization combined with higher order MS/MSn using high-resolution mass spectrometry (APPI-HR-CID-MSn) and electronic structure calculations using density functional theory were used to determine the chemical structure of observed [M-H]+ ions. As a result, the higher order MSn (n = 3) experiments revealed a reversed Diels-Alder fragmentation mechanism, leading to a common fragment ion at m/z 322 from the studied [M1-5-H]+ ion species. In addition, the calculation for two chemical structure models (N-alkyl-TPD1 and N-alkyl-TPD5) showed that the fragment structure, resulting from the removal of the hydrogen atom connected to the third carbon atom of the N-alkyl side chain, has a more stable cyclic form compared with the linear one. The proposed chemical structure of the N-alkyl TPD ion species, following the loss of a single hydrogen atom, was revealed during APPI-HR-CID-MSn (n= 3) experiments on the [M-H]+ species. Hydrogen radical (H•) abstraction from the alkyl side chain (e.g., hexyl, heptyl, octyl, 2-ethylhexyl, and nonyl) triggered a rearrangement in the radical cation structure of the N-alkyl-TPD derivatives, initiating cyclization and forming a six-membered ring that connects the oxygen atom to the third carbon atom in the alkyl chain. In addition, theoretical calculations supported the APPI-HR-CID-MSn (n = 3) experiments by demonstrating that the proposed chemical structure, resulting from the intramolecular cyclization of the N-alkyl-TPD ion species, was stable in the presence of chlorobenzene. These findings will aid the structural determination and elucidation of molecules with similar core structures.

Preparation and Catalytic Properties of Gold Single-Atom and Cluster Catalysts Utilizing Nanoparticulate Mg-Al Layered Double Hydroxides.

Au single atoms and clusters were stabilized on Mg-Al layered double hydroxide nanoparticles (LDH NPs), and the obtained Au@LDH NPs were supported on SiO2 and CeO2. After hydrogen reduction, Au single atoms were found together with Au clusters on LDH/SiO2. In contrast to Au single-atom catalysts which are deposited in metal vacancies of oxide supports, the LDH NPs stabilize very small Au species despite the absence of metal vacancies. The obtained Au(0)@LDH/SiO2 catalyzed aerobic oxidation of alcohols, and Au single atoms maintained after the reaction. Given that only Au NPs were observed on bulk LDH, the abundant surface OH group of LDH NPs would contribute to stabilize Au, resulting in higher activity than Au/LDH-bulk. After calcination to transform LDH to mixed metal oxide (MMO), the obtained Au(0)@MMO/SiO2 also exhibited high catalytic activity. Moreover, Au(0)@LDH/CeO2 exhibited higher activity and excellent selectivity for hydrogenation of 4-nitrostyrene to 4-aminostyrene than conventional Au catalysts such as Au/CeO2 and Au/TiO2. We demonstrated that Au size can be minimized using LDH NPs, exhibiting high catalytic performance. The basic surface OH groups of LDH would be also beneficial for deprotonation of alcohols and heterolytic dissociation of H2 in the catalytic reactions.

Oriented and Continuous Phase Epitaxy Enabled by A Highly Dendrite‐Resistant Plane Toward Super‐High Areal Capacity Zinc Metal Batteries

AbstractUnstable Zn metal anodes with dendrites/side reactions are becoming the main obstacle to the practical application of zinc‐based aqueous batteries. Epitaxial growth has been considered to be an effective strategy for solving these issues, especially for inducing the (002) plane growth. Nonetheless, the (002)‐textured Zn is difficult to achieve highly stable Zn anode under high capacity resulting from its large lattice distortion. Herein, the Cu single atom anchored polymeric carbon nitride (Cu@PCN) is synthesized by a facile thermal polymerization method. Serving as multifunctional protective layer on Zn surface, the Cu@PCN can provide massive nucleation sites at a nano‐level and uniformize the electron distribution through coordination engineering. Optimizing the coordination structures of single Cu and N atoms within the carbon matrix enables a redistribution for electric field and regulates ion flux. More importantly, this coordination strategy with single atoms is first reported to customize oriented and continuous phase epitaxy along highly dendrite‐resistant Zn(101) plane by reducing (101) surface energy. This pattern of oriented dense deposition leads to stable and reversible Zn plating/stripping is achieved, which delivers an extended cycling life of 550 h at 10 A cm−2, 20 mAh cm−2. The practical full cell also displays stable performance for 1200 cycles.

Upcycling of Polyamide Wastes to Tertiary Amines Using Mo Single Atoms and Rh Nanoparticles

AbstractThe pursuit of sustainable practices through the chemical recycling of polyamide wastes holds significant potential, particularly in enabling the recovery of a range of nitrogen‐containing compounds. Herein, we report a novel strategy to upcycle polyamide wastes to tertiary amines with the assistance of H2 in acetic acid under mild conditions (e.g., 180 °C), which is achieved over anatase TiO2 supported Mo single atoms and Rh nanoparticles. In this protocol, the polyamide is first converted into diacetamide intermediates via acidolysis, which are subsequently hydrogenated into corresponding carboxylic acid monomers and tertiary amines in 100 % selectivity. It is verified that Mo single atoms and Rh nanoparticles work together to activate both amide bonds of the diacetamide intermediate, and synergistically catalyze its hydrodeoxygenation to form tertiary amine, but this catalyst is ineffective for hydrogenation of carboxylic acid. This work presents an effective way to reconstruct various polyamide wastes into tertiary amines and carboxylic acids, which may have promising application potential.

Metal Single Atom-Hydroxyl Incorporation in Poly(heptazine imide) to Create Active Sites for Photocatalytic Water Oxidation.

Poly(heptazine imide) (PHI) salts are extensively researched crystalline carbon nitride photocatalysts, but their photocatalytic water oxidation (PWO) performance is scarcely researched because of the difficulty in creating efficient active sites. Interference of metal ion (e.g., Na+ and K+) loss from the PHI salts in their PWO research has hardly been considered. Herein, metal single atom─OH (e.g., Co─OH) groups are incorporated into PHI to create efficient PWO active sites, via simple ion metathesis, hydrolysis, and deprotonation. The Co─OH modified PHI exhibits 9.3-fold higher PWO (oxygen evolution) activity than PHI, with an external quantum yield reaching 0.44% even at 600 nm. Excluding interference of the metal ion loss, the function of the Co─OH incorporation is evidenced mainly to facilitate the oxygen evolution reaction, as well as to promote photogenerated charge separation and raise visible light absorption, with the role of the OH especially revealed. Moreover, it is discovered that Na+ loss from sodium PHI will decrease its PWO activity, protonation of PHI has a detrimental effect on its PWO performance, and some other metal single atom─OH incorporation in PHI can also enhance its PWO activity. Overall, this work provides a general way to create PWO active sites in PHI.

Iron Oxide Clusters as Electron Donors Under Light Enhance Oxygen Reduction Kinetics at Atomically Dispersed Fe for Photocatalytic CH4 Partial Oxidation

AbstractPhotocatalytic CH4 oxidation to CH3OH emerges as a promising strategy to sustainably utilize natural gas and mitigate the greenhouse effect. However, there remains a significant challenge for the synthesis of methanol by using O2 at low temperature. Inspired by the catalytic structure in soluble methane monooxygenase (MMO) and the corresponding reaction mechanism, we prepared a biomimetic photocatalyst with the decoration of Fe2O3 nanoclusters and satellite Fe single atoms immobilized on carbon nitride. The catalyst demonstrates an excellent CH3OH productivity of 5.02 mmol ⋅ gcat−1 ⋅ h−1 with CH3OH selectivity of 98.5 %. Mechanism studies reveal that the synergy between Fe2O3 nanoclusters and Fe single atoms establishes a dual‐Fe site as MMO for O2 activation and subsequent CH4 partial oxidation. Moreover, the light excitation of Fe2O3 nanoclusters with a relative narrow band gap could deliver the electrons and protons to atomic Fe that facilitating the oxygen reduction kinetics for the robust of CH3OH synthesis.

Synergetic Modulation of Electronic Properties of Cobalt Oxide via "Tb" Single Atom for Uphill Urea and Water Electrolysis.

Exploring single-atom (SA) catalysts in hybrid urea-assisted water electrolysis offers a viable alternative to both Hydrogen (H2) generation and polluted water treatment. However, the unfavorable electronic stabilization, low SA content, intrinsically slow kinetics, and imbalanced adsorption-desorption steps are the bottleneck for its scale-up implementation. Herein, a rare-earth Terbium single atom (TbSA) is topologically stabilized on defect-rich Co3O4 (TbSA@d-Co3O4) by Tb─O co-ordination for urea oxidation reaction (UOR) and H2 evolution reaction (HER). Benefitting from the strong TbSA interaction with the d-Co3O4, the TbSA@d-Co3O4 achieves a 10mAcm-2 current density at 1.27V and -35mV for UOR and HER, respectively. Remarkably, when TbSA@d-Co3O4 is applied as a bi-functional catalyst in a two-electrode system, it merely requires 1.22V to acquire 10mAcm-2 with excellent operational stability for 100 h. The hybrid electrolyzer can be successfully empowered by the triboelectric nanogenerator, AA battery, and solar panel with a nominal potential of 1.5V. The mechanistic investigation predicts "TbSA" insertion in d-Co3O4 lowered the potential determining step, attributed to balanced reaction energetics for adsorption-desorption of intermediates and favorable charge transfer characteristics for UOR. This work offers a new paradigm to explore the catalytic properties of rare-earth "f-block" elements to create advanced electrocatalysts via structural modulation.

Redox-Tunable Ring Expansion Enabled By A Single-Component Electrophilic Nitrogen Atom Synthon.

Controllable installation of a single nitrogen atom is central to many major goals in skeletal editing, with progress often gated by the availability of an appropriate N-atom source. Here we introduce a novel reagent, termed DNIBX, based on dibenzoazabicycloheptadiene (dbabh), which allows the electrophilic installation of dbabh to organic substrates. When indanone β-ketoesters are aminated by DNIBX, the resulting products undergo divergent ring expansions depending on the mode of activation, producing heterocycles in differing oxidation states under thermal and photochemical conditions. The mechanism of each transformation is discussed, and the different reactivity modes of the indanone-dbabh adducts are compared to other nitrogenous precursors.

Redox‐Tunable Ring Expansion Enabled By A Single‐Component Electrophilic Nitrogen Atom Synthon

Controllable installation of a single nitrogen atom is central to many major goals in skeletal editing, with progress often gated by the availability of an appropriate N‐atom source. Here we introduce a novel reagent, termed DNIBX, based on dibenzoazabicycloheptadiene (dbabh), which allows the electrophilic installation of dbabh to organic substrates. When indanone β‐ketoesters are aminated by DNIBX, the resulting products undergo divergent ring expansions depending on the mode of activation, producing heterocycles in differing oxidation states under thermal and photochemical conditions. The mechanism of each transformation is discussed, and the different reactivity modes of the indanone‐dbabh adducts are compared to other nitrogenous precursors.

Fe-loaded two-dimensional nitrogen-doped carbon for electromagnetic wave absorption

Abstract Electromagnetic wave absorbing materials are particularly important in modern electronics, especially in the fields of stealth and communications. Carbon-based materials show great promise in the production and application of efficient wave-absorbing materials due to their rich structure, ultra-light weight, good corrosion resistance, and low cost. Among them, nitrogen-doped carbon-based two-dimensional materials have a stronger depletion effect on electromagnetic waves due to their higher specific surface area and abundant polarization states. In this article, nitrogen-doped carbon 2D flakes (NC) were successfully synthesized by a hydrothermal method. Furthermore, Fe single atoms were successfully loaded onto their surfaces, creating Fe@NC. The wave-absorbing properties of Fe@NC samples were significantly enhanced, with the minimum reflection loss (RLmin) reaching -69.22 dB at 11.48 GHz and the effective absorption bandwidth (EAB) extending to 5.79 GHz. The enhancement of electromagnetic wave absorption is attributed to the synergistic effects of magnetic loss, relaxation processes, dipole polarization, and electrical conduction loss. The successful preparation of Fe@NC offers new possibilities for the development of atomically dispersed wave-absorbing materials.

Room Temperature Electrochemical-Shock Synthesis of Solid-Solution Medium-Entropy Alloy Nanoparticles for Hydrogen Evolution.

For millennia, humankind has discovered great benefits in alloying materials. Over the past 100 years, a renaissance in nanoscience has cemented the importance of nanoparticles in a variety of fields ranging from energy storage and conversion to cell biology. While many synthetic strategies exist for nanoparticle and alloy nanoparticle formation, new methods are necessary to create nanoparticles under unprecedented conditions. Here, we demonstrate a simple technique to electrodeposit solid-solution alloy nanoparticles at room temperature. When metal salts of platinum, gold, and palladium are confined to nanodroplets suspended in oil, and then a nanodroplet collides with a sufficiently negative-biased electrode to reduce the metal salts at the mass-transfer limitation, solid-solution alloy nanoparticles form. High-angle annular dark-field scanning transmission electron microscopy and single atom energy dispersive X-ray spectroscopy confirm the solid-solution microstructure of the nanoparticles. The results also confirm the nanodroplet's ability to tune alloy microstructures from amorphous to solid-solution. We further extend our technique by adding salts of silver, which lead to the synthesis of polycrystalline medium-entropy alloys. Finally, we go on to show the application of our midentropy alloys toward renewable and clean energy devices by highlighting their electrocatalytic activity toward hydrogen evolution reaction. Our method is unrivaled in its simplicity and will find applications across various fields of study.

Scalable bottom-up synthesis of Co-Ni-doped graphene.

Introducing heteroatoms into graphene is a powerful strategy to modulate its catalytic, electronic, and magnetic properties. At variance with the cases of nitrogen (N)- and boron (B)-doped graphene, a scalable method for incorporating transition metal atoms in the carbon (C) mesh is currently lacking, limiting the applicative interest of model system studies. This work presents a during-growth synthesis enabling the incorporation of cobalt (Co) alongside nickel (Ni) atoms in graphene on a Ni(111) substrate. Single atoms are covalently stabilized within graphene double vacancies, with a Co load ranging from 0.07 to 0.22% relative to C atoms, controllable by synthesis parameters. Structural characterization involves variable-temperature scanning tunneling microscopy and ab initio calculations. The Co- and Ni-codoped layer is transferred onto a transmission electron microscopy grid, confirming stability through scanning transmission electron microscopy and electron energy loss spectroscopy. This method holds promise for applications in spintronics, gas sensing, electrochemistry and catalysis, and potential extension to graphene incorporation of similar metals.

Location-Specific Microenvironment Modulation Around Single-Atom Metal Sites in Metal-Organic Frameworks for Boosting Catalysis.

Despite coordination environment of catalytic metal sites has been recognized to be of great importance in single-atom catalysts (SACs), a significant challenge remains in the understanding how the location-specific microenvironment in the higher coordination sphere influences their catalysis. Herein, a series of Cu-based SACs, namely Cu1/UiO-66-X (X = -NO2, -H, and -NH2), are successfully constructed by anchoring single Cu atoms onto the Zr-oxo clusters of metal-organic frameworks (MOFs), i.e. UiO-66-X. The -X functional groups dangling on the MOF linkers could be regarded as location-specific remote microenvironment to regulate electronic properties of the single Cu atoms. Remarkably, they exhibit significant differences in the catalysis toward the hydroboration of alkynes. The activity follows the order of Cu1/UiO-66-NO2 ˃ Cu1/UiO-66 ˃ Cu1/UiO-66-NH2 under identical reaction conditions, where Cu1/UiO-66-NO2 showcases the phenylacetylene conversion of 92%, ~3.5 times higher efficiency than that of Cu1/UiO-66-NH2. Experimental and calculation results jointly support that the Cu electronic structure is modulated by the location-specific microenvironment, thereby regulating the product desorption and promoting the catalysis.

Bamboo-derived aerogel with atomically dispersed Co as a high-performance bifunctional electrocatalyst for durable zinc-air batteries

The development of highly efficient and durable bifunctional electrocatalysts is crucial for rechargeable zinc-air batteries, which have garnered significant attention as a promising sustainable energy storage technology. Herein, a novel Co-N-C-1050 catalyst is synthesized using a high-temperature gas transport method, where high purity cobalt powder and bamboo biomass aerogel are treated with ammonia gas at 1050 °C. The resulting catalyst exhibits a 3D interconnected porous network composed of dense carbon fibers, which atomically dispersed Co, N, and C elements are uniformly distributed. The synergistic integration of highly active Co single atoms and N-doped 3D carbon fiber aerogel enables Co-N-C-1050 to demonstrate excellent bifunctional electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), comparable to commercial Pt/C and RuO2 catalysts. This catalyst has a half-wave potential of 0.842 V for ORR and a potential of 1.472 V at 10 mA cm−2 for OER, outperforming N-C-1050 and benchmark catalysts. A zinc-air battery is driven by Co-N-C-1050 achieves a high power density of 135 mW/cm2 and exceptional stability over 138 h of charge/discharge cycling, surpassing the higher-cost Pt/C + RuO2 catalyst. This biomass aerogel based single-site Co-N-C catalyst offers a promising approach for developing high-efficiency and long-cycle-life zinc-air batteries.