Cobalt Center Research Articles

An oxo‐acetato‐bridged trinuclear cobalt(III) cluster‐persuaded cobalt oxide active electrocatalyst for efficient hydrogen evolution activity

This study presents the synthesis and electrocatalytic performance of the cobalt(III) complex [Co3(μ1,1,1‐O)(μ1,3‐CH3CO2)(L)3]2(DMF)3 (Cotri), featuring a double deprotonated (N,O)‐donor ligand (L2‐), where the protonated form of it (H2L) is 2,2′‐(hydrazine‐1,2‐diylidenebis(ethan‐1‐yl‐1‐ylidene))diphenol. The X‐ray structure reveals a trinuclear cobalt cluster formed with three cobalt(III) centers interlinking through oxido (μ1,1,1‐O) and acetato (μ1,3‐O2CCH3) bridges in coupling with bis‐congregator‐type chelating ligands. Cotri adopts cobalt centers of octahedral and trigonal bipyramidal coordination geometries and bears a dominant Co(2)…H(DMF) agostic interactions appraised by lattice dimethyl formamide (DMF) molecules. Further, Cotri shows promising heterogeneous electrocatalytic hydrogen evolution activity in 1 M KOH, with an overpotential of 441 mV to achieve 10 mA/cm2 current density. Tafel slope analysis suggests the Volmer–Heyrovsky step as the rate‐determining step. The number of active sites and TOF for Cotri were estimated at 4.010 × 10−8 mol and 0.2467 s−1, respectively, ensuring its excellent hydrogen generation activity. Stability assessments through controlled potential electrolysis (CPE) and cyclic voltammetry (CV) for multiple cycles addressed the transformation of Cotri to Co2O3 nanoparticles, which turned out to be a more active Co2O3 electrocatalyst. The morphology and particle size of the in situ developed Co2O3 active catalyst under the electrochemical conditions attributes to the superior hydrogen evolution activity.

Operando Spectroscopic Monitoring of Metal Chalcogenides for Overall Water Splitting: New Views of Active Species and Sites

AbstractMetal‐based chalcogenides exhibit great promise for overall water splitting, yet their intrinsic catalytic reaction mechanisms remain to be fully understood. In this work, we employed operando X‐ray absorption (XAS) and in situ Raman spectroscopy to elucidate the structure–activity relationships of low‐crystalline cobalt sulfide (L−CoS) catalysts toward overall water splitting. The operando results for L−CoS catalyzing the alkaline hydrogen evolution reaction (HER) demonstrate that the cobalt centers in the bulk are predominantly coordinated by sulfur atoms, which undergo a kinetic structural rearrangement to generate metallic cobalt in S−Co−Co−S moieties as the true catalytically active species. In comparison, during the acidic HER, L−CoS undergoes local structural optimization of Co centers, and H2 production proceeds with adsorption/desorption of key intermediates atop the Co−S−Co configurations. Further operando characterizations highlight the crucial formation of high‐valent Co4+ species in L−CoS for the alkaline oxygen evolution reaction (OER), and the formation of such active species was found to be far more facile than in crystalline Co3O4 and Co‐LDH references. These insights offer a clear picture of the complexity of active species and site formation in different media, and demonstrate how their restructuring influences the catalytic activity.

Operando Spectroscopic Monitoring of Metal Chalcogenides for Overall Water Splitting: New Views of Active Species and Sites.

Metal-based chalcogenides exhibit great promise for overall water splitting, yet their intrinsic catalytic reaction mechanisms remain to be fully understood. In this work, we employed operando X-ray absorption (XAS) and in situ Raman spectroscopy to elucidate the structure-activity relationships of low-crystalline cobalt sulfide (L-CoS) catalysts toward overall water splitting. The operando results for L-CoS catalyzing the alkaline hydrogen evolution reaction (HER) demonstrate that the cobalt centers in the bulk are predominantly coordinated by sulfur atoms, which undergo a kinetic structural rearrangement to generate metallic cobalt in S-Co-Co-S moieties as the true catalytically active species. In comparison, during the acidic HER, L-CoS undergoes local structural optimization of Co centers, and H2 production proceeds with adsorption/desorption of key intermediates atop the Co-S-Co configurations. Further operando characterizations highlight the crucial formation of high-valent Co4+ species in L-CoS for the alkaline oxygen evolution reaction (OER), and the formation of such active species was found to be far more facile than in crystalline Co3O4 and Co-LDH references. These insights offer a clear picture of the complexity of active species and site formation in different media, and demonstrate how their restructuring influences the catalytic activity.

Encapsulated Dye in Coordination-Assembled Octahedron for Visible-Light-Driven Proton Reduction and Nitroaromatic Hydrogenation.

To mimic the finely tuned natural photosynthetic systems, a large metal-organic octahedron was synthesized by one-pot self-assembly with modified triphenylamine ligands and redox-active cobalt ions. By encapsulating an organic dye, fluorescein (Fl), within the inner cavity of the octahedron, the host-guest supramolecular system was provided for light-driven hydrogen production. The intimate distance between the redox site and the photosensitizer in the supramolecular metal-organic cage allowed the photoinduced electrons to transfer from the excited state Fl* to the redox cobalt center in a pseudo-intramolecular pathway. The supramolecular system showed good performance in light-driven hydrogen production and the reduction of nitroaromatic compounds. Control experiments based on a mononuclear compound resembling a cobalt corner of the octahedron and inhibitor competition provided evidence of enzyme-like catalytic behavior. The supramolecular reaction pathways within confined spaces contribute to the superior activity of the host-guest system.

The study of rate constants of redox reactions on cobalt (III) complexes of α-hydroxy acids with quinolinium chlorochromate (QCC) in micellar medium

Complexes of QCC with bound and unbound alpha-hydroxy acids of Co (III) in the micellar medium is unable to obtain some sort of electron transport mode kinetics in the medium. Unbound and bound hydroxy acids are oxidised by QCC, which also oxidizes Cobalt (III). The Cobalt (III) centre cannot receive an electron while the C-C bond is being split. These compounds’ oxidation rates rise in direct proportion to their temperature. When the concentration of surfactant is increased, the rate increases. More than ammonium laurylsuphate, DDAC can speed up the oxidation of the process (ALS). A similar pattern was found in the Co (III) complexes containing lactato, glycolato, and mandelato.

Cobalamin decyanation by the membrane transporter BtuM

BtuM is a bacterial cobalamin transporter that binds the transported substrate in the base-off state, with a cysteine residue providing the α-axial coordination of the central cobalt ion via a sulfur-cobalt bond. Binding leads to decyanation of cobalamin variants with a cyano group as the β-axial ligand. Here, we report the crystal structures of untagged BtuM bound to two variants of cobalamin, hydroxycobalamin and cyanocobalamin, and unveil the native residue responsible for the β-axial coordination, His28. This coordination had previously been obscured by non-native histidines of His-tagged BtuM. A model in which BtuM initially binds cobinamide reversibly with low affinity (KD= 4.0μM), followed by the formation of a covalent bond (rate constant of 0.163 s-1), fits the kinetics data of substrate binding and decyanation of the cobalamin precursor cobinamide by BtuM. The covalent binding mode suggests a mechanism not used by any other transport protein.

Rare-Earth Metalloligands for Low-Valent Cobalt Complexes: Fine Electronic Tuning via Co→RE Dative Interactions.

Rare-earth metalloligand supported low-valent cobalt complexes were synthesized by utilizing a small-sized heptadentate phosphinomethylamine LsNH3 and a large-sized arene-anchored hexadentate phosphinomethylamine LlArH3 ligand precursors. The RE(III)-Co(-I)-N2 (RE = Sc, Lu, Y, Gd, La) complexes containing rare-earth metals including the smallest Sc and largest La were characterized by multinuclear NMR spectroscopy, X-ray diffraction analysis, electrochemistry, and computational studies. The Co(-I)→RE(III) dative interactions were all polarized with major contributions from the 3dz2 orbital of the cobalt center, which was slightly affected by the identity of rare-earth metalloligands. The IR spectroscopic data and redox potentials obtained from cyclic voltammetry revealed that the electronic property of the Co(-I) center was finely tuned by the rare-earth metalloligand, which was revealed by variation of the ligand systems containing LsN, LmN, and LlAr. Unlike the direct alteration of the electronic property of metal center via an ancillary ligand, such a series of rare-earth metalloligand represents a smooth strategy to tune the electronic property of transition metals.

Mechanistic Insights into Electrocatalytic Hydrogen Evolution by an Exceptionally Stable Cobalt Complex.

Co(aPPy) is one of the most stable and active molecular first-row transition-metal catalysts for proton reduction reported to date. Understanding the origin of its high performance via mechanistic studies could aid in developing even better catalysts. In this work, the catalytic mechanism of Co(aPPy) was electrochemically probed, in both organic solvents and water. We found that different mechanisms can occur depending on the solvent and the acidity of the medium. In organic solvent with a strong acid as the proton source, catalysis initiates directly after a single-electron reduction of CoII to CoI, whereas in the presence of a weaker acid, the cobalt center needs to be reduced twice before catalysis occurs. In the aqueous phase, we found drastically different electrochemical behavior, where the Co(aPPy) complex was found to be a precatalyst to a different electrocatalytic species. We propose that in this active catalyst, the pyridine ring has dissociated and acts as a proton relay at pH ≤ 5, which opens up a fast protonation pathway of the CoI intermediate and results in a high catalytic activity. Furthermore, we determined with constant potential bulk electrolysis that the catalyst is most stable at pH 3. The catalyst thus functions optimally at low pH in an aqueous environment, where the pyridine acts as a proton shuttle and where the high acidity also prevents catalyst deactivation.

An insight into the non-covalent Cl•••Cl interaction in the solid state structure of carboxylate bridged trinuclear mixed valence cobalt(III/II/III) complexes with tetradentate N2O2 donor reduced Schiff base ligands

Two mixed-valence trinuclear cobalt(III)-cobalt(II)-cobalt(III) complexes, [CoII{(μ-L1)(μ-OOCC6H5NO2)CoIII(N3)}2] (1) and [CoII{(μ-L2)(μ-OOCC6H4NO2CH3)CoIII(N3}2] (2) have been synthesized using two tetradentate N2O2 donor 'reduced Schiff base' ligands, H2L1 {2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(4-chlorophenol}, and H2L2{2-hydroxy-1,3-propanediyl)bis(iminomethylene)bis(4-chlorophenol}, and 3-nitrobenzoic benzoic acid or 4-methyl 3-nitrobenzoic benzoic acid as anionic co-ligands. The complexes have been characterized by spectroscopic measurements and their solid state structures have been determined by single crystal X-ray diffraction analysis. The trinuclear cobalt(III)-cobalt(II)-cobalt(III) skeleton of both the complexes are linear and centrosymmetric. Both the central cobalt(II) and terminal cobalt(III) of both the complexes are hexa-coordinated. DFT calculations have been used to analysed some supramolecular assemblies of the complex that have been observed in the solid state, specifically the Cl···Cl interactions that result in the creation of a stable 2D supramolecular assembly in the solid state. QTAIM and NCI Plot computational tools have been used to characterize the interactions. Thermo-gravimetric (TG) analysis was used to examine the thermal behaviour of both complexes. The redox behaviors of both the complexes were studied by using Cyclic Voltammetry (CV).

Light-Controlled Multiconfigurational Conductance Switching in a Single 1D Metal-Organic Wire.

Precise control of multiple spin states on the atomic scale presents a promising avenue for designing and realizing magnetic switches. Despite substantial progress in recent decades, the challenge of achieving control over multiconfigurational reversible switches in low-dimensional nanostructures persists. Our work demonstrates multiple, fully reversible plasmon-driven spin-crossover switches in a single π-d metal-organic chain suspended between two electrodes. The plasmonic nanocavity stimulated by external visible light allows for reversible spin crossover between low- and high-spin states of different cobalt centers within the chain. We show that the distinct spin configurations remain stable for minutes under cryogenic conditions and can be nonperturbatively detected by conductance measurements. This multiconfigurational plasmon-driven spin-crossover demonstration extends the available toolset for designing optoelectrical molecular devices based on SCO compounds.

Synthesis, structural characterization and antitumor activities of manganese and cobalt isothiocyanate complexes with 2,2’-bipyridine

[Mn(SCN)2(2,2′-bipy)2] (1) and [Co(SCN)2(2,2′-bipy)2] (2) were synthesized at ambient temperature by adding aqueous solutions of manganese(II) or cobalt(II) chloride hydrate to aqueous acetonitrile solutions of 2,2′-bipyridine (2,2′-bipy) and potassium thiocyanate. Elemental analyses, FT-IR and UV–vis spectra were used to characterize 1 and 2. Single crystal X-ray diffraction was used to analyze the crystal structures of 1 and 2, revealing that the two are structurally similar. The molecular structures of 1 and 2 consist of Mn or Co ion chelated by two molecules of 2,2′-bipy through four nitrogen atoms and two NCS anions, giving distorted octahedral geometries. The isothiocyanate group is not bridging, instead, two ligands coordinate in a cis arrangement to the manganese or cobalt center by their nitrogen atoms while the sulfur atoms are free. Through hydrogen bonding and π–π stacking interactions, the discrete units of 1 and 2 extend to 3D supramolecular networks with flower and fishbone-like structures. The luminescence behavior of 2,2′-bipy, 1 and 2 were investigated. On HepG2 (liver) and MCF-7 (breast) cancer cells, the anticancer effects of 1 and 2 were evaluated. The activity of 1 and 2 on MCF-7 is more significant than that of HepG2. The IC50 of 1 was lower in HepG2 and MCF-7 cells than for 2.

Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine-Oxazoline-Ligated Cobalt Complexes.

A family of pyridine-oxazoline-ligated cobalt complexes L2CoCl23a-h were synthesized and characterized. Determined via single-crystal X-ray diffraction, complexes 3a and 3d, ligated by two ligands, displayed a distorted tetrahedral coordination of a cobalt center. The X-ray structure indicated the pyridine-oxazoline ligands acted as unusual mono-dentate ligands by coordinating only to Noxazoline. Upon activation with AlEt2Cl (diethylaluminum chloride), these cobalt complexes all exhibited high catalytic activity (up to 2.5 × 106 g·molCo-1·h-1), affording cis-1,4-co-3,4-polyisoprene with molecular weights of 4.4-176 kg mol-1 and a narrow Ð of 1.79-3.42, suggesting a single-site nature of the active sites. The structure of cobalt catalysts and reaction parameters, especially co-catalysts and the reaction temperature, all have significant influence on the polymerization activity but not on the microstructure of polyisoprene.

Cobalt‐Mediated [3+1] Fragmentation of White Phosphorus: Access to Acylcyanophosphanides

AbstractDespite the accessibility of numerous transition metal polyphosphido complexes through transition‐metal‐mediated activation of white phosphorus, the targeted functionalization of Pn ligands to obtain functional monophosphorus species remains challenging. In this study, we introduce a new [3+1] fragmentation procedure for cyclo‐P4 ligands, leading to the discovery of acylcyanophosphanides and ‐phosphines. Treatment of the complex [K(18c‐6)][(Ar*BIAN)Co(η4‐P4)] ([K(18c‐6)]3, 18c‐6=[18]crown‐6, Ar*=2,6‐dibenzhydryl‐4‐isopropylphenyl, BIAN=1,2‐bis(arylimino)acenaphthene diimine) with acyl chlorides results in the formation of acylated tetraphosphido complexes [(Ar*BIAN)Co(η4‐P4C(O)R)] (R=tBu, Cy, 1‐Ad, Ph; 4 a–d). Subsequent reactions of 4 a–d with cyanide salts yield acylated cyanophosphanides [RC(O)PCN]− (9 a–d−) and the cyclo‐P3 cobaltate anion [(Ar*BIAN)Co(η3‐P3)(CN)]− (8−). Further reactions of 4 a–d with trimethylsilyl cyanide (Me3SiCN) and isocyanides provide insight into a plausible mechanism of this [3+1] fragmentation reaction, as these reagents partially displace the P4C(O)R ligand from the cobalt center. Several potential intermediates of the [3+1] fragmentation were characterized. Additionally, the introduction of a second acyl substituent was achieved by treating [K(18c‐6)]9b with CyC(O)Cl, resulting in the first bis(acyl)monocyanophosphine (CyC(O))2PCN (10).

Cobalt-Mediated [3+1] Fragmentation of White Phosphorus: Access to Acylcyanophosphanides.

Despite the accessibility of numerous transition metal polyphosphido complexes through transition-metal-mediated activation of white phosphorus, the targeted functionalization of Pn ligands to obtain functional monophosphorus species remains challenging. In this study, we introduce a new [3+1] fragmentation procedure for cyclo-P4 ligands, leading to the discovery of acylcyanophosphanides and -phosphines. Treatment of the complex [K(18c-6)][(Ar*BIAN)Co(η4 -P4 )] ([K(18c-6)]3, 18c-6=[18]crown-6, Ar*=2,6-dibenzhydryl-4-isopropylphenyl, BIAN=1,2-bis(arylimino)acenaphthene diimine) with acyl chlorides results in the formation of acylated tetraphosphido complexes [(Ar*BIAN)Co(η4 -P4 C(O)R)] (R=tBu, Cy, 1-Ad, Ph; 4 a-d). Subsequent reactions of 4 a-d with cyanide salts yield acylated cyanophosphanides [RC(O)PCN]- (9 a-d- ) and the cyclo-P3 cobaltate anion [(Ar*BIAN)Co(η3 -P3 )(CN)]- (8- ). Further reactions of 4 a-d with trimethylsilyl cyanide (Me3 SiCN) and isocyanides provide insight into a plausible mechanism of this [3+1] fragmentation reaction, as these reagents partially displace the P4 C(O)R ligand from the cobalt center. Several potential intermediates of the [3+1] fragmentation were characterized. Additionally, the introduction of a second acyl substituent was achieved by treating [K(18c-6)]9b with CyC(O)Cl, resulting in the first bis(acyl)monocyanophosphine (CyC(O))2 PCN (10).

Low-spin to low-spin valence tautomeric transition in cobalt bis-dioxolenes.

Cobalt dioxolenes are a well-known class of switchable coordination compounds showing intramolecular electron transfer, which is always accompanied by a spin state change at the cobalt center. Here, we present the first example of thermally switchable cobalt bis-dioxolenes where intramolecular electron transfer seems to take place, but the spin state change is suppressed. This leads to the detection of thermal transition between a common ls-CoIII(SQ˙-)(Cat2-) and an extremely rare ls-CoII(SQ˙-)2 electronic state (hs - high-spin, ls - low-spin, SQ˙- - benzosemiquinonate(1-) radical and Cat2- - catecholate(2-)). Parallel to the present work, a similar work but on cobalt mono-dioxolenes has just appeared (Chem. Eur. J., 2023, 29, e202300091), suggesting thermal transition between ls-CoIII(Cat2-) and ls-CoII(SQ˙-) electronic states.

Unveiling photoinduced electron transfer in cobalt(iii)-R-pyridine complexes anchored to anatase nanocrystals: photoluminescence and magnetic studies.

In this study, we synthesized mixed ligand complexes of the cis-[Co(tn)2(Rpy)Br]Br2 type using a novel mechanochemical approach. Characterization involved spectral measurements and single crystal X-ray diffraction analysis, confirming the structure of the cis-[Co(tn)2(4-Mepy)Br]Br2 complex. The single crystal refinement data revealed a monoclinic crystal system with a distorted octahedral geometry. The choice of the sixth ligand influenced the emission and magnetic properties, showing a ferromagnetic character in the Co(iii)-complex environment. We investigated efficient electron transfer to the cobalt(iii) center using TiO2 nanoparticles under UV-light irradiation. The adsorption characteristics of cis-[Co(tn)2(Rpy)Br]Br2 in aqueous 2-propanol varied, leading to surface compound formation. Under UV irradiation, the anatase surface exhibited remarkable adsorption capabilities, facilitating efficient electron transfer to the Co(iii) center and resulting in a high photoefficiency for Co(ii) formation. Our study has put forward a model for interfacial electron transfer (IET), taking into account the overlap between the TiO2 conduction band and the acceptor level of the Co center, as well as the electronic coupling between the donor level of the Ti center and the acceptor level of the Co center. This model sheds light on the accumulation of electrons for reducing the adhered complex ion. The IET process was corroborated by the conversion of 2-propanol into acetone, as verified by 1H NMR technique. Overall, our findings provide novel insights into the role of the Rpy moiety in modifying the structure of the TiO2-cobalt(iii)-Rpy compound and propose a mechanism for IET reactions, thus advancing the field.

Effect of Apical Ligands, Substituents and Oxidation States on the Electronic Structure of Co(III) Corrolates

AbstractCobalt(III) corroles are the most commonly studied types of metallocorroles, yet the details of their electronic structure, ground spin states and place of redox events are not always straightforward. Corroles are redox active, potentially non‐innocent ligands, and it has been found through various experimental and computational techniques, that the innocent or non‐innocent behavior is modulated by the apical ligands bound to the cobalt center. In this work, we aim to analyze the effect of corrole substituents and number and type of apical ligands on the electronic structure of cobalt corroles through density functional and wavefunction theories, and to determine the relative energies between closed‐ and open‐shell states. We further perform preliminary analyses on the place of electron abstraction upon oxidation and on the effect of the corrole and apical ligands on the cobalt ligand field splittings. We find that both ligand field and electron‐donating or withdrawing effects determine the relative energies of open‐shell and closed shell singlet states.

Tartrate bridging ligands in divalent Co(II)/Co(III) dinuclear anion

A cobalt(II/III) ionic compound with bridging tartaric acid (H4L) anion (CH6N3)3[Co2II/III(L)2(H2O)2]·4H2O 1 was synthesized. The crystallites were isolated from highly alkaline aqueous solution in the presence of guanidinium cations (CH6N3)+ being then incorporated as counter ions.A determined structure reveals the dinuclear coordination anion with two cobalt centers, each within its distinctive coordination octahedron CoO6 sphere showing different Co−O bond lengths. The metal center with shorter coordination bonds is assigned as Co(III), while the other with Co(II), all in agreement with overall net charge equilibrium. This involves three guanidinium cations, two tartrate(4-) anions, the latter within the coordination anion, as well as with bond valence sums for both cobalt centers. Both tartrates (L) are triply bonded on the Co(III) center, thus enabling CoIIIO6 coordination bonds. On the other hand, only two coordination bonds are enabled by each tartrate towards Co(II), while the remaining two in CoIIO6 are completed by two terminal water molecules. The electronic spectrum shows clearly the d-d bands at 400 and 665 nm for Co(III), while at 520 nm for Co(II), for each CoO6, respectively. The temperature dependent magnetic susceptibility shows the paramagnetic behavior of the compound, due to the d7 Co(II) ions being in a high spin state, while the d6 low spin Co(III) ions are diamagnetic.

Catalytic Behavior of Cobalt Complexes Bearing Pyridine-Oxime Ligands in Isoprene Polymerization.

Several cobalt(II) complexes Co1-Co3 bearing pyridine-oxime ligands (L1 = pyridine-2-aldoxime for Co1; L2 = 6-methylpyridine-2-aldoxime for Co2; L3 = phenyl-2-pyridylketoxime for Co3) and picolinaldehyde O-methyl oxime (L4)-supported Co4 were synthesized and well characterized by FT-IR, mass spectrum and elemental analysis. The single-crystal X-ray diffraction of complex Co2 reveals that the cobalt center of CoCl2 is coordinated with two 6-methylpyridine-2-aldoxime ligands binding with Npyridine and Noxime atoms, which feature a distorted octahedral structure. These Co complexes Co1-Co4 displayed extremely high activity toward isoprene polymerization upon activation with small amount of AlClEt2 in toluene, giving polyisoprene with high activity up to 16.3 × 105 (mol of Co)-1(h)-1. And, the generated polyisoprene displayed high molecular weights and narrow molecular distribution with a cis-1,4-enriched selectivity. The type of cobalt complexes, cocatalyst and reaction temperature all have effects on the polymerization activity but not on the microstructure of polymer.

Cation Concavities Induced d-Band Electronic Modulation on Co/FeOx Nanostructure to Activate Molecular and Interfacial Oxygen for CO Oxidation.

Cobalt-based catalysts have been identified for effective CO oxidation, but their activity is limited by molecular O2 and interfacial oxygen passivation at low temperatures. Optimization of the d-band structure of the cobalt center is an effective method to enhance the dissociation of oxygen species. Here, we developed a novel Co/FeOx catalyst based on selective cationic deposition to anchor Co cations at the defect site of FeOx, which exhibited superior intrinsic low-temperature activity (100%, 115 °C) compared to that of Pt/Co3O4 (100%, 140 °C) and La/Co2O3 (100%, 150 °C). In contrast to catalysts with oxygen defects, the cationic Fe defect in Co/FeOx showed an exceptional ability to accept electrons from the Co 3d orbital, resulting in significant electron delocalization at the Co sites. The Co/FeOx catalyst exhibited a remarkable turnover frequency of 178.6 per Co site per second, which is 2.3 times higher than that of most previously reported Co-based catalysts. The d-band center is shifted upward by electron redistribution effects, which promotes the breaking of the antibonding orbital *π of the O═O bond. In addition, the controllable regulation of the Fe-Ov-Co oxygen defect sites enlarges the Fe-O bond from 1.97 to 2.02 Å to activate the lattice oxygen. Moreover, compared to CoxFe3-xO4, Co/FeOx has a lower energy barrier for CO oxidation, which significantly accelerates the rate-determining step, *COO formation. This study demonstrates the feasibility of modulating the d-band structure to enhance O2 molecular and interfacial lattice oxygen activation.