Local Coordination Environment Research Articles

Metal-Coordinated Phthalocyanines as Platform Molecules for Understanding Isolated Metal Sites in the Electrochemical Reduction of CO2.

Single-atom catalysts (SACs) of non-precious transition metals (TMs) often show unique electrochemical performance, including the electrochemical carbon dioxide reduction reaction (CO2RR). However, the inhomogeneity in their structures makes it difficult to directly compare SACs of different TM for their CO2RR activity, selectivity, and reaction mechanisms. In this study, the comparison of isolated TMs (Fe, Co, Ni, Cu, and Zn) is systematically investigated using a series of crystalline molecular catalysts, namely TM-coordinated phthalocyanines (TM-Pcs), to directly compare the intrinsic role of the TMs with identical local coordination environments on the CO2RR performance. The combined experimental measurements, in situ characterization, and density functional theory calculations of TM-Pc catalysts reveal a TM-dependent CO2RR activity and selectivity, with the free energy difference of ΔG(*HOCO) - ΔG(*CO) being identified as a descriptor for predicting the CO2RR performance.

Atomically dispersed 3d metal bimetallic dual-atom catalysts and classification of the structural descriptors

Solid atomic catalysts with well-defined and complex structures are believed to effectively bridge homogeneous and heterogeneous catalysis. Nonetheless, the current limited capacity of “precise engineering” in solid atomic catalysts has led to structural heterogeneity and thus unsatisfactory catalytic selectivity. Here, we show that late 3 d metal cations, such as Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+ , can be assembled to afford combinations of “dual atoms” within zeolitic micropores, and this clearly avoids issues like uncontrolled metal aggregation during synthesis. In this work, by the quantitative evaluation of the structural descriptors over a probe superoxide dismutation reaction, we demonstrate the unique synergistic advantage between (i) neighboring bimetallic active motifs, (ii) tertiary structure around the zeolitic support, and (iii) the local coordination environment. The identification and tunability of the structural descriptors shown in this work unravel a reliable approach to the precise engineering of next-generation solid dual-atom catalysts. • Atom-precise synthesis of supported bimetallic dual-atom catalysts • Reliable approach for precise microenvironment engineering in solid catalysts • Discovery of the interplay between the structural descriptors and catalytic properties • Demonstration of synergistic effect with sorafenib for augmented tumor cell apoptosis We aim to present a creative approach to afford dual-atom bimetallic catalysts in a controlled and modular manner. This directly allows the combinations of different late 3 d metals (forming M 1 -M 2 -supported dual atoms) and shows extensive possibility not limited to catalytic applications. Through the unique synergistic advantage between the two metal species and the tertiary structure around the zeolitic support, we demonstrated the feasibility of developing next-generation dual-atom bimetallic catalysts in a controlled manner as well as the identification of the structural descriptors. The manipulation and control of materials and phenomena at atomic and molecular dimensions are achieved by utilizing the fundamental concepts of coordination and solid-state chemistries. The findings presented in this work reveal the precise engineering of supported dual-atom catalysts (such as combinations of 3 d /4 d metals) over support materials not only for biochemical applications but also for more extensive applications. This shall genuinely bring heterogeneous catalysis toward the molecular frontier that addresses the critical challenges in the field.

C2H2 hydrochlorination over the diatomic RuM catalysts anchored over the N-doped graphene: Influences of metal M type and coordination environment

Catalytic performance of N-doped graphene supported diatomic catalysts is closely related to the coordination environment and the metal types of active center. In this work, the influences of the second metal M type and local coordination environment in the N-doped graphene anchored RuM diatomic catalysts on C2H2 hydrochlorination activity were unraveled. The results showed that the metal M type and local coordination environment (N6V4 and N8V4) of RuM diatomic catalysts effectively regulate C2H2 hydrochlorination activity, attributing to the unique electronic properties of diatomic active sites caused by the metal M type and local coordination environment. Among sixteen types of RuM diatomic catalysts considered, five types of low-cost RuSn-N6V4, RuCo-N6V4, RuCu-N6V4, RuAu-N8V4 and RuCo-N8V4 catalysts were screened out to exhibit excellent C2H2 hydrochlorination activity, and AIMD simulations further confirmed better thermal stability of these five catalysts at 453 K. These predication needs to be checked via further experiments. This work identifies the role of the coordination environment and the type of active metal for N-doped graphene supported RuM diatomic catalysts in regulating C2H2 hydrochlorination activity, and helps rational design of high-performance and low-cost RuM diatomic catalysts by tuning the local coordination environment and the types of the second metal M.

Doping-Mediated Size and Structure Tailoring of CaS Nanocrystals

Lanthanide-doped CaS crystals are extensively studied as light-emitting materials, but the investigation of CaS nanocrystals is largely lagging. This work reports a doping-induced modification of surface charge density and the local coordination environment in CaS:Ce nanocrystals, which offers precise control over the nanocrystal size (39–14 nm) and emission color (green to yellow). Our mechanistic investigations, corroborated by theoretical calculations, reveal a S-enriched nanocrystal surface that accommodates excess charges of the aliovalent lanthanide dopants. Owing to the altered surface structure, we identify a dark Ce state that selectively extinguishes light emission of the CaS:Ce nanocrystals. We demonstrate that the doping-induced surface effects can be offset by coating the CaS:Ce nanocrystals with an undoped CaS shell, giving rise to a shell-thickness-dependent emission. Our findings suggest that nanocrystals may respond differently to impurity dopants than the corresponding bulk crystals, thereby giving rise to extended control over materials properties for applications such as optical encryption.

Actinides in complex reactive media: A combined ab initio molecular dynamics and machine learning analytics study of transuranic ions in molten salts

The predominant ionic chemistry and the similarity in ionic radius of actinides make it very difficult to structurally distinguish them in liquids. To tackle this problem, we investigate actinides in molten salts using ab initio molecular dynamics and machine learning analytics. Ab initio simulations show that the f-states clearly affects the electronic properties while their impact on structural properties is not obvious. For the series of trivalent actinides U3+, Pu3+, Cm3+, Cf3+, and Fm3+ in molten NaCl and FLiBe, actinide-ligand bonds have a higher degree of covalency in NaCl (than in FLiBe), and a higher degree of ionicity in FLiBe. Furthermore, a machine learned classification model can distinguish atomic environments of chemically similar actinides with more than 80% confidence, as long as atoms beyond the first solvation shells are considered. Our work shows that only two types of descriptors are necessary to account for all the fluctuations in heavy metal/molten salt mixtures: The first descriptor represents the electronic state of the heavy metal, while the second encompasses the local coordination environment.

Determine the coordination of Al and Si of Fe-rich fly ash: The challenge in NMR and how we probe its heterogeneity using X-ray spectromicroscopy

Scanning transmission X-ray microscopy (STXM) coupled with ptychographic imaging at Al and Si K-edge is a new probe to the microscale chemistry of heterogenous materials. Here, the combined techniques are applied to study local coordination environment of Fe-rich fly ash (FA). Ptychographic imaging at Al K- and Si K-edge highlights the fine Al- and Si-rich morphological features, respectively, at 6 nm pixel resolution. STXM visualizes the inter- and intra-particle variations in the silicate polymerization degree and two types of Al coordination environment in FA. The Si K-edge of SiO4 connected with four-fold coordinated Al is higher than SiO4 sharing oxygen with six-fold coordinated Al. The result is consistent with bulk nuclear magnetic resonance spectroscopy measurement of the Fe-rich sample which, however, is sensitive to paramagnetic Fe and time-consuming. We demonstrate that the combined method has great potential in the studies of chemically heterogenous aluminosilicates.

Two‐Dimensional Organometallic Frameworks with Pyridinic Single‐Metal‐Atom Sites for Bifunctional ORR/OER

AbstractAchieving efficient bifunctional oxygen reduction and evolution reactions (ORR/OER) on non‐noble metal catalysts is desirable but remains a significant challenge. Herein, inspired by the experimentally synthesized (phen2N2)FeCl molecule, a stable 2D organometallic framework, namely (phen2N2)FeCl monolayer, is proposed as a qualified candidate by means of constant‐potential first‐principles computations. Unlike most 2D organometallic frameworks that feature pyrrolic coordination, the (phen2N2)FeCl monolayer exhibits a pyridinic‐type FeN4 ligation environment. The unique structure of the monolayer enables a high single‐atom Fe loading in a heterogeneous system, superior to the typical FeNC materials. Constant‐potential energy analysis and microkinetic modeling demonstrate that the monolayer holds great potential for facilitating bifunctional ORR/OER in both the acidic and alkaline conditions, showing theoretical activity higher than the FeNC materials, (phen2N2)FeCl molecule, and Pt/IrO2. Moreover, (phen2N2)MCl monolayers (M = Mn, Co, and Ni) are explored, and the (phen2N2)MnCl monolayer is also identified to have excellent bifunctional activity. This study highlights the rational design of local coordination environments for boosting the electrocatalytic performance of 2D organometallic frameworks.

Macro/Micro-Environment RegulatingCarbon-Supported Single-Atom Catalysts for Hydrogen/Oxygen Conversion Reactions.

Single-atom catalysts (SACs) have attracted tremendous research interest due to their unique atomic structure, maximized atom utilization, and remarkable catalytic performance. Among the SACs, the carbon-supported SACs have been widely investigated due to their easily controlled properties of the carbon substrates, such as the tunable morphologies, ordered porosity, and abundant anchoring sites. The electrochemical performance of carbon-supported SACs is highly related to the morphological structure of carbon substrates (macro-environment) and the local coordination environments of center metals (micro-environment). This review aims to provide a comprehensive summary on the macro/micro-environment regulating carbon-supported SACs for highly efficient hydrogen/oxygen conversion reactions. The authors first summarize the macro-environment engineering strategies of carbon-supported SACs with altered specific surface areas and porous properties of the carbon substrates, facilitating the mass diffusion kinetics and structural stability. Then the micro-environment engineering strategies of carbon-supported SACs are discussed with the regulated atomic structure and electronic structure of metal centers, boosting the catalytic performance. Insights into the correlation between the co-boosted effect from the macro/micro-environments and catalytic activity for hydrogen/oxygen conversion reactions are summarized and discussed. Finally, the challenges and perspectives are addressed in building highly efficient carbon-supported SACs for practical applications.

Homogeneity of Supported Single-Atom Active Sites Boosting the Selective Catalytic Transformations.

Selective conversion of specific functional groups to desired products is highly important but still challenging in industrial catalytic processes. The adsorption state of surface species is the key factor in modulating the conversion of functional groups, which is correspondingly determined by the uniformity of active sites. However, the non‐identical number of metal atoms, geometric shape, and morphology of conventional nanometer‐sized metal particles/clusters normally lead to the non‐uniform active sites with diverse geometric configurations and local coordination environments, which causes the distinct adsorption states of surface species. Hence, it is highly desired to modulate the homogeneity of the active sites so that the catalytic transformations can be better confined to the desired direction. In this review, the construction strategies and characterization techniques of the uniform active sites that are atomically dispersed on various supports are examined. In particular, their unique behavior in boosting the catalytic performance in various chemical transformations is discussed, including selective hydrogenation, selective oxidation, Suzuki coupling, and other catalytic reactions. In addition, the dynamic evolution of the active sites under reaction conditions and the industrial utilization of the single‐atom catalysts are highlighted. Finally, the current challenges and frontiers are identified, and the perspectives on this flourishing field is provided.

Design Principles for the Development of Gd(III) Polarizing Agents for Magic Angle Spinning Dynamic Nuclear Polarization

Nuclear magnetic resonance suffers from an intrinsically low sensitivity, which can be overcome by dynamic nuclear polarization (DNP). Gd(III) complexes are attractive exogenous polarizing agents for magic angle spinning (MAS) DNP due to their high chemical stability in contrast to nitroxide-based radicals. However, even the state-of-the-art Gd(III) complexes have so far provided relatively low DNP signal enhancements of ca. 36 in comparison to standard DNP biradicals, which show enhancements of over 200. Here, we report a series of new Gd(III) complexes for DNP and show that the observed DNP enhancements of the new and existing Gd(III) complexes are inversely proportional to the square of the zero-field splitting (ZFS) parameter D, which is in turn determined by the ligand-type and the local coordination environment. The experimental DNP enhancements at 9.4 T and the ZFS parameters measured with pulsed electron paramagnetic resonance (EPR) spectroscopy agree with the above model, paving the way for the development of more efficient Gd(III) polarizing agents.

Triazine organic framework derived Fe single-atom bifunctional electrocatalyst for high performance zinc air batteries

Owing to their adjustable local structure and coordination environment, Fe single-metal site electrocatalysts become superior alternatives to the precious metal-based systems for oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). However, they often suffer from complicated preparation methods. The optimized conditions hide in a narrow window and require a large amount of screening work. Moreover, the porous support may collapse during high temperature, resulting in dead volume and low atomic usage efficiency. Herein we report a facile build-up of atomically dispersed Fe single metal site (Fe–N–C) derived from Fe-doped thermalized covalent triazine frameworks (TTF) towards bifunctional ORR/OER catalysts. The TTF-derived carbon provides a platform for the formation and uniform dispersion of single-atom Fe–N catalytic centers. A high electrocatalytic behavior towards ORR (E1/2 = 0.891 V) and OER (Ej = 10 = 1.543 V) in alkaline medium is achieved with excellent stability and anti-methanol poisoning activity. Impressively, its metal mass activity is 62 times higher than commercial 20 wt% Pt/C. The Zn-air battery (ZAB) based on the catalyst achieves a high capacity of 783.2 mAh g−1, a low voltage gap of 0.55 V and an outstanding rechargeability of 1650 cycles (∼550 h), placing it as one of the best-performing ZABs.

Revealing the interfacial electron modulation effect of CoFe alloys with CoC encapsulated in N-doped CNTs for superior oxygen reduction

Rationally designing and developing robust and durable electrocatalytic materials for oxygen reduction/evolution are essential for metal−air batteries. Herein, an effective approach is proposed to fabricate high-performance electrocatalysts based on CoFe alloy and CoC X nanoparticles sandwiched in nitrogen-doped carbon nanotubes. The preparation of CoFe−CoC X @NCNT is achieved by the calcination of CoFe 2 O 4 spinel and dicyandiamide under reducing atmosphere. The CoFe−CoC X @NCNT catalyst exhibits remarkable oxygen reduction reaction (ORR) performance with the onset and half-wave potential of 1.01 ​V and 0.89 ​V, respectively, exceeding the commercial Pt/C catalyst. Furthermore, the Zn−air battery using CoFe−CoC X @NCNT as air cathode shows a power density of 175 ​mW ​cm −2 , which is also higher than that of the industrial Pt/C ​+ ​RuO 2 . The super electrocatalytic performance is attributed to the multiple heterointerface and strong coupling effect among CoFe, CoC X , and NCNT, which can regulate conductivity and electron structure of the catalyst. This study supplies a practical strategy to exploit active and low-cost catalytic material for Zn−air batteries, and presents an in-depth insight into the designing of efficient green energy storage devices. Herein, the CoFe-CoC X @NCNT exhibits an outstanding ORR performance with onset potential of 1.01 ​V and half-wave potential of 0.89 ​V, exceeding the commercial Pt/C catalyst. Furthermore, the Zn-air battery performance assembled by CoFe-CoC X @NCNT shows the power density of 175 ​mW ​cm −2 is also better than that of the commercial Pt/C ​+ ​RuO 2 . The excellent performance is attributed to the multiple heterogeneous interfaces and strong coupling between CoFe alloy, CoC X , and NCNT, which are helpful to drive fast reaction kinetics and regulate local coordination environment and electronic structure. This work provides a new approach to design excellent active and low-cost catalysts for Zn-air batteries, which presents an in-depth insight into the development of efficient green energy storage devices.

Manipulating concentration quenching and thermal stability of Eu3+-activated NaYbF4 nanoparticles via phase transition strategy toward diversified applications

Red-emitting phosphors play a vital role in reinforcing the quality of phosphor-converted white light-emitting diodes. Unfortunately, concentration quenching and unsatisfied thermal stability are still the inevitable shortcomings of the red-emitting phosphors. Herein, we utilized phase transition to simultaneously tailor the concentration quenching and thermal stability of Eu3+-activated NaYbF4 (NaYbF4:xEu3+) nanoparticles, in order to overcome these limitations. With the increasing doping level, the resultant samples undergo a phase transition from cubic to hexagonal phase. Notably, the optimal doping content for Eu3+ in the NaYbF4 nanoparticles with cubic phase is 30 mol%. However, when the phase transition occurs, the concentration quenching takes place at a much higher doping concentration, i.e. the optimum content of Eu3+ in the structure is increased to about 80 mol%. Moreover, with elevating the Eu3+ content, the local coordination environment of Eu3+ in the NaYbF4 host lattice is changed from inversion (centrosymmetric) to non-inversion symmetry (non-centrosymmetric), which is further confirmed by the theoretical calculation results via Judd-Oflet theory. Furthermore, compared with cubic samples, the hexagonal NaYbF4:0.8Eu3+ nanoparticles show improved thermal stability. Importantly, utilizing hexagonal NaYbF4:0.8Eu3+ nanoparticles, a designed white light-emitting diode emits warm white light, with desired color coordinates (0.398,0.374), high color rendering index (86.3), and low correlated color temperature (3537 K). Besides, NaYbF4:xEu3+ nanoparticles and their flexible polydimethylsiloxane films exhibit potential applications in high-temperature optical anti-counterfeiting. This work may support a new perspective for tailoring the concentration quenching and thermal stability of various phosphors.

Improving C–N–FeOx Oxygen Evolution Electrocatalysts through Hydroxyl-Modulated Local Coordination Environment

Improving C–N–FeO_<i>x</i> Oxygen Evolution Electrocatalysts through Hydroxyl-Modulated Local Coordination Environment

Identifying Key Descriptors for the Single-Atom Catalyzed CO Oxidation

Identifying Key Descriptors for the Single-Atom Catalyzed CO Oxidation

X-ray absorption spectroscopy study of Mn reference compounds for Mn speciation in terrestrial surface environments

Abstract X-ray absorption spectroscopy (XAS) offers great potential to identify and quantify Mn species in surface environments by means of linear combination fit (LCF), fingerprint, and shell-fit analyses of bulk Mn XAS spectra. However, these approaches are complicated by the lack of a comprehensive and accessible spectrum library. Additionally, molecular-level information on Mn coordination in some potentially important Mn species occurring in soils and sediments is missing. Therefore, we investigated a suite of 32 natural and synthetic Mn reference compounds, including Mn oxide, oxyhydroxide, carbonate, phosphate, and silicate minerals, as well as organic and adsorbed Mn species, by Mn K-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The ability of XAS to infer the average oxidation state (AOS) of Mn was assessed by comparing XANES-derived AOS with the AOS obtained from redox titrations. All reference compounds were studied for their local (&amp;lt;5 Å) Mn coordination environment using EXAFS shell-fit analysis. Statistical analyses were employed to clarify how well and to what extent individual Mn species (groups) can be distinguished by XAS based on spectral uniqueness. Our results show that LCF analysis of normalized XANES spectra can reliably quantify the Mn AOS within ~0.1 v.u. in the range +2 to +4. These spectra are diagnostic for most Mn species investigated, but unsuitable to identify and quantify members of the manganate and Mn(III)-oxyhydroxide groups. First-derivative XANES fingerprinting allows the unique identification of pyrolusite, ramsdellite, and potentially lithiophorite within the manganate group. However, XANES spectra of individual Mn compounds can vary significantly depending on chemical composition and/or crystallinity, which limits the accuracy of XANES-based speciation analyses. In contrast, EXAFS spectra provide a much better discriminatory power to identify and quantify Mn species. Principal component and cluster analyses of k2-weighted EXAFS spectra of Mn reference compounds implied that EXAFS LCF analysis of environmental samples can identify and quantify at least the following primary Mn species groups: (1) Phyllo- and tectomanganates with large tunnel sizes (2 × 2 and larger; hollandite sensu stricto, romanèchite, todorokite); (2) tectomanganates with small tunnel sizes (2 × 2 and smaller; cryptomelane, pyrolusite, ramsdellite); (3) Mn(III)-dominated species (nesosilicates, oxyhydroxides, organic compounds, spinels); (4) Mn(II) species (carbonate, phosphate, and phyllosilicate minerals, adsorbed and organic species); and (5) manganosite. All Mn compounds, except for members of the manganate group (excluding pyrolusite) and adsorbed Mn(II) species, exhibit unique EXAFS spectra that would allow their identification and quantification in mixtures. Therefore, our results highlight the potential of Mn K-edge EXAFS spectroscopy to assess bulk Mn speciation in soils and sediments. A complete XAS-based speciation analysis of bulk Mn in environmental samples should preferably include the determination of Mn valences following the “Combo” method of Manceau et al. (2012), EXAFS LCF analyses based on principal component and target transformation results, as well as EXAFS shell-fit analyses for the validation of LCF results. For this purpose, all 32 XAS reference spectra are provided in the Online Materials1 for further use by the scientific community.

Coordination environment tuning of nickel sites by oxyanions to optimize methanol electro-oxidation activity

To achieve zero-carbon economy, advanced anode catalysts are desirable for hydrogen production and biomass upgrading powered by renewable energy. Ni-based non-precious electrocatalysts are considered as potential candidates because of intrinsic redox attributes, but in-depth understanding and rational design of Ni site coordination still remain challenging. Here, we perform anodic electrochemical oxidation of Ni-metalloids (NiPx, NiSx, and NiSex) to in-situ construct different oxyanion-coordinated amorphous nickel oxyhydroxides (NiOOH-TOx), among which NiOOH-POx shows optimal local coordination environment and boosts electrocatalytic activity of Ni sites towards selective oxidation of methanol to formate. Experiments and theoretical results demonstrate that NiOOH-POx possesses improved adsorption of OH* and methanol, and favors the formation of CH3O* intermediates. The coordinated phosphate oxyanions effectively tailor the d band center of Ni sites and increases Ni-O covalency, promoting the catalytic activity. This study provides additional insights into modulation of active-center coordination environment via oxyanions for organic molecules transformation.

Atomic-level modulation of local coordination environment at Fe single-atom sites for enhanced oxygen reduction

Single-atom catalysts (SACs) have aroused extensive attention due to their ultrahigh activity and selectivity. However, precisely regulating and designing the coordination microenvironment of SACs to optimize the catalytic efficiency remains a great challenge. Here, a facile ionic liquid (IL) modification strategy is creatively proposed to obtain N and P dual-coordinated Fe single atoms with N unsaturated coordination on pre-designed FeSAC-N4/C sites. The using a hydrophobic IL can alter the binding affinity of O2, maintain a higher O2 concentration at the catalyst interface, and protect Fe single atom sites from surface oxidation and methanol toxicity. Theoretical calculation indicates that this unique coordination and the N vacancy can tailor the electronic structure of the metal atoms and alter the charge distribution at the coordination structures, thus improving the oxygen reduction reaction performance. This study offers an effective approach for accurately controlling the coordination electronic structure and interface environment of SACs at room temperature.

Antimony speciation, phytochelatin stimulation and toxicity in plants

Antimony (Sb) is a toxic metalloid that has been listed as a priority pollutant. The environmental impacts of Sb have recently attracted attention, but its phytotoxicity and biological transformation remain poorly understood. In this study, Sb speciation and transformation in plant roots was quantified by Sb K-edge X-ray absorption spectroscopy. In addition, the phytotoxicity of antimonate (SbV) on six plant species was assessed by measuring plant photosynthesis, growth, and phytochelatin production induced by SbV. Linear combination fitting of the Sb K-edge X-ray absorption near-edge structure (XANES) spectra indicated reduction of SbV was limited to ∼5–33% of Sb. The data confirmed that Sb-polygalacturonic acid was the predominant chemical form in all plant species (up to 95%), indicating Sb was primarily bound to the cell walls of plant roots. Shell fitting of Sb K-edge X-ray absorption fine-structure (EXAFS) spectra confirmed Sb–O and Sb–C were the dominant scattering paths. The fitting indicated that SbV was bound to hydroxyl functional groups of cell walls, via development of a local coordination environment analogous to Sb-polygalacturonic acid. This is the first study to demonstrate the key role of plant cell walls in Sb metabolism.

Control in Local Coordination Environment Boosting Activating Molecular Oxygen with an Atomically Dispersed Binary Mn–Co Catalyst

Activation of molecular oxygen plays a crucial role in natural organisms and the modern chemical industry. Herein, we report a Mn-Co dual-single-atom catalyst that exerts a specific synergy in boosting O2 activation by collaboration between two distinct types of activation sites. Taking the oxidative esterification of the biomass platform 5-hydroxymethylfurfural (HMF) as the model reaction, the activation of O2 is demonstrated through transforming O2 into a reactive superoxide anion radical (O2•-) on Co-N4 sites and, meanwhile, by reversible consumption and supplement of coordinated surface oxygen as a new type of reactive oxygen species (ROS) on N,O-coordinated single-atom Mn sites (Mn-NxOy). EXAFS analysis results show a longer average Mn-O bond distance at near 2.19 Å, which makes the breaking and formation of surface Mn-O bonds easier to cycle. Control experiments support that such Mn-O bonding conditions could facilitate H-elimination of C-H in HMF. The co-existence of two types of ROS effectively matches the oxidation of hydroxyl and aldehyde groups, and thus, the overall reaction is boosted in excellent yield of diester (95.8%) with an extremely high carbon balance. This study represents a rare example of taking advantage of the synergy of the diatomic catalyst for activating O2 by two types of activation pathways.