Oxygen Activation Research Articles

Activating Oxygen via the 3‐Electron Pathway to Hydroxyl Radical by La‐O4 Single‐atom on WO3 for Water Purification

Shifting photocatalytic oxygen activation towards 3‐electron (e‐) pathway to hydroxyl radicals, instead of the normal 1 e‐ to superoxide radicals, becomes increasingly important for pollution degradation since hydroxyl radicals possess a high oxidation potential (2.80 V). Here, we demonstrate a selective oxygen activation to hydroxyl radicals via 3 e‐ pathway using single atomically dispersed La based on WO3 fabricated with oxygen vacancies to weaken La‐O coordination strength (denoted as LaO4‐WOv). Unsaturated‐state La overcomes the rate‐limited step of 2 e‐ oxygen reduction reaction towards to hydrogen peroxide via tuning binding free energy of key reaction intermediate *OOH, stepped by easy generation of hydroxyl radicals via 1 e‐. This strategy alters the activation of oxygen process from 1 e‐ to 3 e‐. Hydrogen peroxide and hydroxyl radicals over LaO4‐WOv produces 3.8 and 3.3 mmol L‐1 h‐1, 35 and 8 times that of detected over WO3, respectively. Rapid and complete removal of tetracycline realizes over LaO4‐WOv with 0.077 min‐1 of rate constant, 38 times that of WO3. Degradation efficiencies keep greater than 98% following five repeats, revealing a practical‐utilization‐level robust stability. This work builds an unsaturated‐state transition metal site for manipulating oxygen activation towards an effective water purification as a representative application.

Activating Oxygen via the 3‐Electron Pathway to Hydroxyl Radical by La‐O4 Single‐atom on WO3 for Water Purification

Shifting photocatalytic oxygen activation towards 3‐electron (e‐) pathway to hydroxyl radicals, instead of the normal 1 e‐ to superoxide radicals, becomes increasingly important for pollution degradation since hydroxyl radicals possess a high oxidation potential (2.80 V). Here, we demonstrate a selective oxygen activation to hydroxyl radicals via 3 e‐ pathway using single atomically dispersed La based on WO3 fabricated with oxygen vacancies to weaken La‐O coordination strength (denoted as LaO4‐WOv). Unsaturated‐state La overcomes the rate‐limited step of 2 e‐ oxygen reduction reaction towards to hydrogen peroxide via tuning binding free energy of key reaction intermediate *OOH, stepped by easy generation of hydroxyl radicals via 1 e‐. This strategy alters the activation of oxygen process from 1 e‐ to 3 e‐. Hydrogen peroxide and hydroxyl radicals over LaO4‐WOv produces 3.8 and 3.3 mmol L‐1 h‐1, 35 and 8 times that of detected over WO3, respectively. Rapid and complete removal of tetracycline realizes over LaO4‐WOv with 0.077 min‐1 of rate constant, 38 times that of WO3. Degradation efficiencies keep greater than 98% following five repeats, revealing a practical‐utilization‐level robust stability. This work builds an unsaturated‐state transition metal site for manipulating oxygen activation towards an effective water purification as a representative application.

Fluorine‐Induced Lattice Oxygen Participation in 2D Layered Double Hydroxide/MXene Hybrids for Efficient Oxygen Evolution

AbstractIn oxygen evolution reaction (OER), the participation of lattice oxygen can break the limitation of adsorption evolution mechanism, but the activation of lattice oxygen remains a critical challenge. Herein, a surface fluorinated highly active 2D/2D FeNi layered double hydroxide/MXene (F‐LDH/MX) is demonstrated, boosting OER with the enhanced lattice‐oxygen‐mediated path. The introduction of fluorine promotes the self‐evolution of catalyst in an alkaline environment, even without an external current. It further accelerates the formation of active metal oxyhydroxides with abundant oxygen vacancies under the operating potential. The introduced oxygen vacancy activates the lattice oxygen, increasing the proportion of lattice oxygen mechanism in OER. Owing to the synergistic effects of the 2D/2D hierarchical structure and the modulated active surface, F‐LDH/MX possesses excellent electrochemical performances, including a low overpotential of 251 mV at 10 mA cm−2, a low Tafel slope of 40.28 mV dec−1, and robust stability. The water electrolyzer system with F‐LDH/MX as the anode offers the benchmark current density at a low cell voltage of 1.53 V, while the Zn‐air battery with F‐LDH/MX as the air electrode exhibits a higher power density of 75.43 mW cm−2. This study presents a promising strategy to design highly active electrocatalysts for energy conversion and storage.

Cation Migration‐Induced Lattice Oxygen Oxidation in Spinel Oxide for Superior Oxygen Evolution Reaction

Activating the lattice oxygen can significantly improve the kinetics of oxygen evolution reaction (OER), however, it often results in reduced stability due to the bulk structure degradation. Here, we develop a spinel Fe0.3Co0.9Cr1.8O4 with active lattice oxygen by high‐throughput methods, achieving high OER activity and stability, superior to the benchmark IrO2. The oxide exhibits an ultralow overpotential (190 mV at 10 mA cm–2) with outstanding stability for over 170 h at 100 mA cm–2. Soft X‐ray absorption‐ and Raman‐spectroscopies, combined with 18O isotope‐labelling experiments, reveal that lattice oxygen activation is driven by Cr oxidation, which induces a cation migration from CrO6 octahedrons to CrO4 tetrahedrons. The geometry conversion creates accessible non‐bonding oxygen states, crucial for lattice oxygen oxidation. Upon oxidation, peroxo O–O bond is formed and further stabilized by Cr6+ (CrO4 tetrahedra) via dimerization. This work establishes a new approach for designing efficient catalysts that feature active and stable lattice oxygen without compromising structural integrity.

Cation Migration‐Induced Lattice Oxygen Oxidation in Spinel Oxide for Superior Oxygen Evolution Reaction

Activating the lattice oxygen can significantly improve the kinetics of oxygen evolution reaction (OER), however, it often results in reduced stability due to the bulk structure degradation. Here, we develop a spinel Fe0.3Co0.9Cr1.8O4 with active lattice oxygen by high‐throughput methods, achieving high OER activity and stability, superior to the benchmark IrO2. The oxide exhibits an ultralow overpotential (190 mV at 10 mA cm–2) with outstanding stability for over 170 h at 100 mA cm–2. Soft X‐ray absorption‐ and Raman‐spectroscopies, combined with 18O isotope‐labelling experiments, reveal that lattice oxygen activation is driven by Cr oxidation, which induces a cation migration from CrO6 octahedrons to CrO4 tetrahedrons. The geometry conversion creates accessible non‐bonding oxygen states, crucial for lattice oxygen oxidation. Upon oxidation, peroxo O–O bond is formed and further stabilized by Cr6+ (CrO4 tetrahedra) via dimerization. This work establishes a new approach for designing efficient catalysts that feature active and stable lattice oxygen without compromising structural integrity.

Polarized electric field-mediated graphitic carbon nitride-based S-scheme heterostructure for efficient photocatalytic removal of bisphenol A

Tuning interface charge transfer is considered as a feasible way to promote electron migration and separation in heterojunction system, but the role of in-plane electron behavior in single phase has received little attention. Here, a carboxyl functionalized graphitic carbon nitride (CCN) coupled PbBiO2Br (PBOB) S-scheme heterostructure is elaborately designed for investigation. Compared with pristine CN/PBOB, although the existence of carboxyl group weakens the built-in electric field strength of CCN/PBOB (ΔΦ = 0.44 eV), the formed polarized electric field (µ = 3.18 Debye) is conducive to the pre-separation of photogenerated electrons and holes in CCN, thereby improving interface charge transfer. In addition, the introduced carboxyl group can also serve as an O2 adsorption site to enhance its activation, and generate reactive oxygen species (ROS) through a two-step single-electron O2 reduction route. Thus, the optimized CCN/PBOB exhibits excellent photocatalytic ROS generation ability, which can remove 88.7 % of bisphenol A and significantly reduce the acute toxicity of the formed intermediates. This work provides a new perspective for the development of advanced heterojunction photocatalyst by regulating in-plane/interface charge dynamics, and helps to fully understand the pollutant detoxification/degradation process initiated by molecular oxygen activation.

Constructing frustrated Lewis pairs on Mo-doped Fe2O3 catalyst to enhance oxidative desulfurization efficiency

The emission of sulfur oxides will not only cause a series of environmental pollution but also threaten human health. At present, oxidative desulfurization is considered one of the technologies to achieve high-efficiency conversion of sulfur-containing compounds. Herein, the special frustrated Lewis pairs (FLPs) for efficient oxidative desulfurization are created by regulating surface doping in a redox iron-based oxide. According to experimental results, the Lewis acidic sites can be considered as the iron atoms adjacent to the molybdenum dopant, while the doped metal proximal to the oxygen vacancies serves as Lewis basic sites to create FLPs in redox iron-based oxide. This reactivity of FLPs is further adapted to the chemical activation of molecular oxygen and aromatic sulfur-containing compounds. The Fe2O3-FLP catalyst can achieve 100 % sulfur removal at 3 h and maintains 96.9 % after seven cycles, higher than other previously reported iron-based oxidative desulfurization catalysts. In addition, the design of FLPs offers a promising approach for developing high-efficiency catalysts in the oxidative desulfurization process.

Electrochemical Synthesis of Nitrite and Nitrate via Cathodic Oxygen Activation in Liquefied Ammonia.

The electrochemical oxidation of ammonia (NH3) enables decentralized small-scale synthesis of nitrate (NO3-) and nitrite (NO2-) under ambient conditions by directly utilizing renewable energy. Yet, their electrosynthesis has been restricted to aqueous media and low ammonia concentrations. For the first time, we demonstrate here a strategy enabling the direct electrooxidation of liquefied NH3 to NO3- and NO2- by using molecular oxygen, achieving combined Faraday efficiencies above 40%.

Carbon defect induced electron transfer promotes electrocatalytic activation of molecular oxygen to selectively generate singlet oxygen for pollutants removal

This study explored the design of heterojunctions incorporating defective graphene and boron nitride (BN) to activate molecular oxygen (O₂) and degrade sulfamethoxazole (SMX) by establishing efficient electron transport channels. These heterojunction catalysts, designed using theoretical predictions, were synthesized by controlling carbon defect concentration and pyrolysis temperature. The optimized GBN cathode achieved a maximum SMX degradation rate of 0.0252min⁻¹, with a total organic carbon (TOC) removal efficiency of 47.31%. Singlet oxygen (¹O₂) was identified as the primary reactive oxygen species, exhibiting a generation rate of 18.66μMmin⁻¹ and contributing 93.5% to SMX degradation. Results demonstrated that an optimal defect concentration enhances electron transfer, promoting the 2-electron reduction of O₂ to H₂O₂ and facilitating further H₂O₂ activation, thereby accelerating SMX degradation. This work advances the development of non-metallic cathodic catalysts and provides valuable insights into electrochemical degradation mechanisms for organic pollutants.

Mofs-derived transition metal carbon-based compounds supported Au-Pt catalyst for the catalytic oxidation of glycerol to glyceric acid

Accurately controlling the directional activation of the primary and secondary hydroxyls and preventing the deep oxidation of oxygen-containing functional groups and the degree of C–C cleavage is still a great challenge for the selective oxidation of glycerol to glyceric acid. Hence, a series of bimetallic Au-Pt/MxOyCz catalysts (M = Cu, Co, Ce, Mn, Ni, Zn, Zr) were prepared using MOFs-derived transition metal carbon-based compounds as the support. These catalysts were utilized for glycerol catalytic oxidation to glyceric acid under basic conditions. The experimental date indicated that the type of transition metal makes a big difference on the conversion of glycerol and the selectivity of glyceric acid under the mild condition of 60 ℃. Among them, the Mn-modified carbon-based compound supported Au-Pt/MnxOyCz catalyst has the best catalytic activity. After reaction for 2 h, the conversion of glycerol could reach 100 %, and the selectivity of glyceric acid could reach 57.3 %. The reason for the best activity of the Au-Pt/MnxOyCz catalyst is that the particle size of active molecules is small, and the strong metal-support interaction produces more active sites. Specifically, Au-Pt/MnxOyCz catalyst forms an Au-Pt alloy, and the synergy between alloyed Au-Pt and Mn&+ enhances the acidity of the catalyst, causing it to produce the most acidic sites and promoting the dispersion of metal nanoparticles. The strong basic site of the catalyst can promote Au-Pt electron transfer, which in turn changes the reducing properties of Au-Pt and enriches the oxygen vacancies of the catalyst. Therefore, the synergistic interaction between the acidic sites and strong basic sites promotes the activation of Au-Pt, which in turn promotes the reduction of Mn-based oxides and the activation and migration of oxygen. This work will offer some new recommendations for the development of MOFs-derived transition metal-based catalysts for the catalytic oxidation of bio-polyols under mild conditions.

A novel protein elicitor (Cs08297) from Ciboria shiraiana enhances plant disease resistance.

Ciboria shiraiana is a necrotrophic fungus that causes mulberry sclerotinia disease resulting in huge economic losses in agriculture. During infection, the fungus uses immunity elicitors to induce plant tissue necrosis that could facilitate its colonization on plants. However, the key elicitors and immune mechanisms remain unclear in C. shiraiana. Herein, a novel elicitor Cs08297 secreted by C. shiraiana was identified, and it was found to target the apoplast in plants to induce cell death. Cs08297 is a cysteine-rich protein unique to C. shiraiana, and cysteine residues in Cs08297 were crucial for its ability to induce cell death. Cs08297 induced a series of defence responses in Nicotiana benthamiana, including the burst of reactive oxygen species (ROS), callose deposition, and activation of defence-related genes. Cs08297 induced-cell death was mediated by leucine-rich repeat (LRR) receptor-like kinases BAK1 and SOBIR1. Purified His-tagged Cs08297-thioredoxin fusion protein triggered cell death in different plants and enhanced plant resistance to diseases. Cs08297 was necessary for sclerotial development, oxidative-stress adaptation, and cell wall integrity but negatively regulated virulence of C. shiraiana. In conclusion, our results revealed that Cs08297 is a novel fungal elicitor in fungi inducing plant immunity. Furthermore, its potential to enhance plant resistance provides a new target to control agricultural diseases biologically.

TSPO Exacerbates Sepsis-Induced Cardiac Dysfunction by Inhibiting p62-Mediated Autophagic Flux via the ROS-RIP1/RIP3-Exosome Axis

Septic cardiomyopathy (SCM) is a critical complication of sepsis, primarily attributed to mitochondrial dysfunction and impaired autophagic flux. This study explores the role of translocator protein (TSPO) in SCM pathogenesis and assesses its potential as a therapeutic target. We identified increased TSPO expression in plasma samples from sepsis patients, with further validation in septic rats and LPS-stimulated H9C2 cardiomyocytes. Elevated TSPO disrupted mitochondrial function, leading to increased reactive oxygen species (ROS) production and activation of the RIP1/RIP3 pathway, which hindered p62-positive autophagosome degradation and promoted inflammation. Moreover, exosome release containing TSPO-positive autophagosomes into plasma may exacerbate systemic inflammation. NADH, identified as a TSPO-binding molecule, restored autophagic flux, improved mitochondrial function, and enhanced cardiac performance and survival in septic rats. These findings suggest that targeting TSPO with NADH could alleviate mitochondrial dysfunction and inflammatory responses in SCM, providing a promising therapeutic strategy for sepsis-induced cardiac injury.

Spin-Orbit Interaction During the Activation of Molecular Oxygen by Oxidases and Cofactor-Free Oxygenases: A Review

Spin-Orbit Interaction During the Activation of Molecular Oxygen by Oxidases and Cofactor-Free Oxygenases: A Review

Incorporating Si into NiO support to facilitate oxygen activation for CH4 combustion

In this study, high-performance Pd/NiO-Si catalysts for lean methane oxidation were synthesized using the solution combustion and impregnation method. The incorporation of silicon in NiO promoted the generation of Ni2+ and strengthened the metal-support interaction. This enhanced interaction promoted the generation and movement of active oxygen species on surface, which are essential for maintaining Pd species in an active oxidized state, thereby ensuring the effective activation of CH4. The Pd/NiO-Si catalyst with an optimal amount of Si exhibited an excellent catalytic performance, achieving a T90 of 440 °C for methane oxidation under wet conditions. The elemental doping strategy in this study, which significantly enhances the production of highly active oxygen species with strong mobility, plays a crucial role in the effective utilization of precious metals such as Pd.

Efficient Photocatalytic Oxidative Coupling of Amines under Visible Light Using a Trioporphyrins-Based Covalent Triazine Framework.

Porphyrins-based porous organic polymers (POP) were widely used in photocatalytic oxidation under visible light owing to their superiority in the activation of oxygen. In contrast, the efficiency is usually limited due to the fast recombination and slow electron transfer. Herein, we report the use of a trioporphyrins-based covalent triazine framework (Por-CTF) as visible-light-active photocatalyst for the coupling oxidative of amines to imines at room temperature. By incorporating the π-conjugated porphyrin building block led to the enhanced electron transport between molecules, and the extended recombination time of excited electrons. The photocatalytic efficiency of Por-CTF is superior to that of polymer in absence of triazine framework (POP-TSP), which was prepared by radical polymerization using tetra-(4-vinylphenyl) porphyrin (TSP) as monomer. Por-CTF catalyst presented excellent efficiency for various primary amines and stability. This work provides a reasonable guidance of catalyst molecular structure design for enhancing efficiency in the photocatalytic oxidation.

Carbonized Polymer Dots-Promoted Photocatalytic Activation of Molecular Oxygen for Efficient and Selective Oxidation of Thioethers to Sulfoxides.

Sulfoxides are essential in pharmaceuticals and chemicals, yet traditional thioether oxidation struggles with selectivity and sustainability. This study introduces carbonized polymer dots (CPDs) as effective photocatalysts for ecofriendly thioether to sulfoxide oxidation, using water and ethanol to enhance reaction selectivity and efficiency under 455 nm blue light. These catalysts not only show remarkable efficacy under mild conditions but also display high selectivity for sulfoxide formation, proving versatile across a broad range of substrates. We further elucidated the catalytic mechanism, confirming the predominant roles of singlet oxygen and superoxide anions through both spectroscopic evidence and quenching experiments. The method extends to the synthesis of pharmaceuticals such as oxfendazole, albendazole sulfoxide, and sulindac, highlighting its practical utility. Overall, our findings present a sustainable and efficient avenue for sulfoxide synthesis, thereby broadening the practical utility of CPDs in photocatalytic transformations.

Photocatalytic H2O2 production over boron-doped g-C3N4 containing coordinatively unsaturated FeOOH sites and CoOx clusters

Graphitic carbon nitride (g-C3N4) has gained increasing attention in artificial photosynthesis of H2O2, yet its performance is hindered by sluggish oxygen reduction reaction (ORR) kinetics and short excited-state electron lifetimes. Here we show a B-doped g-C3N4 (BCN) tailored with coordinatively unsaturated FeOOH and CoOx clusters for H2O2 photosynthesis from water and oxygen without sacrificial agents. The optimal material delivers a 30-fold activity enhancement compared with g-C3N4 under visible light, with a solar-to-chemical conversion efficiency of 0.75%, ranking among the forefront of reported g-C3N4-based photocatalysts. Additionally, an electron transfer efficiency reaches 34.1% for the oxygen reduction reaction as revealed by in situ microsecond transient absorption spectroscopy. Experimental and theoretical results reveal that CoOx initiates hole–water oxidation and prolongs the electron lifetime, whereas FeOOH accepts electrons and promotes oxygen activation. Intriguingly, the key to the direct one-step two-electron reaction pathway for H2O2 production lies in coordinatively unsaturated FeOOH to adjust the Pauling-type adsorption configuration of O2 to stabilize peroxide species and restrain the formation of superoxide radicals.

Recent Progress in Molecular Oxygen Activation by Iron-Based Materials: Prospects for Nano-Enabled In Situ Remediation of Organic-Contaminated Sites

Recent Progress in Molecular Oxygen Activation by Iron-Based Materials: Prospects for Nano-Enabled In Situ Remediation of Organic-Contaminated Sites

Interface engineering to construct heterostructured MoO3/SmMn2O5 for chemical looping oxidative dehydrogenation of ethane

Electronic structure and lattice oxygen in metal oxides play important roles in the chemical looping oxidative dehydrogenation of ethane. Herein, an interface strategy is proposed to tailor electronic structure and activate lattice oxygen of mullite SmMn2O5 via the interface fabrication with MoO3 for enhancing the reactivity of the sample. The optimized 2MoO3/SmMn2O5 oxygen carrier exhibited 50 % ethane conversion and 83.9 % ethylene selectivity higher than that of pure SmMn2O5 and pure MoO3. Density functional theory simulations and characterization results revealed that the interface of MoO3/SmMn2O5 regulated the d-band center, which tailored the adsorption of ethane. Besides, the interface of MoO3/SmMn2O5 also caused the charge transfer from Mn atoms in SmMn2O5 to O atoms in MoO3 and SmMn2O5, leading to a reduction of the Mn-O bond strength and an enhancement in the activity of the lattice oxygen and Oads. This study provides useful insights to regulate electronic structure and activate lattice oxygen of oxygen carrier through interfacial engineering for the practical application of ethane chemical looping oxidative dehydrogenation.

Boosted 1,2-Dichloroethane Deep Destruction over CoRu/Al2O3 Bifunctional Catalysts via Surface Oxygen and Water Molecule Synergistic Activation.

Developing efficacious catalysts with superior Cl resistance and polychlorinated byproduct inhibition capability is crucial for realizing the environmentally friendly purification of chlorinated volatile organic compounds (CVOCs). Activating CVOC molecules and desorbing Cl species by modulating the metal-oxygen property is a promising strategy to fulfill these. Herein, a bifunctional CoRu/Al2O3 catalyst with synergistic Co and Ru interactions (Ru-O-Co species) was rationally fabricated, which possesses abundant surface Co2+ and Ruδ+ sites and collaboratively facilitates the activation of lattice oxygen (O2-) and molecular oxygen (O2 → O2- → O-), accelerating 1,2-dichloroethane (1,2-DCE) decomposition via the reaction route of enolic species → aldehydes → carboxylate/carbonate. Furthermore, CoRu/Al2O3 stimulates 1,2-DCE oxidation under humid conditions as H2O molecules can be easily activated to active *OH (potential oxidizing agent) over Ru species, accelerating C-Cl dissociation and Cl desorption and promoting the transformation of catecholate-type (C═O) species to easily oxidizable carboxylic acid (COOH) species, remarkably suppressing the formation of hazardous CCl4 and CHCl2CH2Cl. This study provides critical insights into the development of bifunctional catalysts to synergistically activate surface oxygen species and H2O molecules for industrial CVOC stable and efficient elimination.