EPR Techniques Research Articles

WS2-Assisted Electrochemical Activation of Peroxymonosulfate for Eliminating Organic Pollutant in Water

Advanced oxidation process based on heterogeneous activation of peroxymonosulfate (PMS) has received significant attention in wastewater remediation. Herein, a facile and effective electrochemical method was introduced in a tungsten sulfide (WS2)-activated PMS process for the removal of a typical azo dye Acid Orange 7 (AO7) in aqueous solution. It was found that the electrochemical activation could remarkably promote the removal of organic pollutants by coupling with WS2/PMS system. The elimination of AO7 in the electro-assisted WS2-activated PMS (E/WS2/PMS) system achieved 95.8% of AO7 removal in 30 min, with the optimal conditions of 1.0 g/L WS2, 1.0 mM PMS, current density of 1.0 mA/cm2 and initial pH of 6.5. Based on quenching experiments and EPR techniques, mechanistic studies confirmed that hydroxyl radical (•OH) and singlet oxygen (1O2) are the primary reactive oxygen species for the oxidation of pollutants. In addition, the influences of pH, WS2 dosage, PMS concentration, current density, common anions and humic acid on the AO7 removal are also investigated in detail. Furthermore, the system exhibited resistance to aqueous matrices, verifying the accepted applicability in real water (i.e., Yangtze River water and Shahu Lake water). In summary, this study demonstrates a green system for the effective removal of contaminants in water, holding significant implications for practical application.

Interface and Defect Engineering in 3D Co3O4‐Ov/TiO2 to Boost Simultaneous Removal of BPA and Cr(VI) upon Photoelectrocatalytic/Peroxymonosulfate (PEC/PMS) System

AbstractThe combination of photoelectrocatalytic (PEC) and peroxymonosulfate (PMS) is an innovative strategy for environmental treatment. And fabricating a highly efficient photoelectrode is the most pivotal factor in PEC reactions. This study designs an advanced Co3O4‐Ov/TiO2 photoelectrode by a dual‐modification strategy encompassing interface engineering and defect engineering. The photoelectric characterization validates the synergy of oxygen vacancies and dual heterojunctions. Simulated electron density distribution and Kelvin probe force microscopy (KPFM) elucidate the charge transfer pathway between Co3O4‐Ov and TiO2. 1O2 and SO4 .− are confirmed to be primarily responsible for the BPA oxidation in PEC/PMS system by radical scavenger experiments and the EPR technique. And the attack sites of BPA are precisely identified based on the Fukui index. Furthermore, density functional theory (DFT) calculations testify that Co3O4‐Ov can improve the adsorption capacity of PMS and reduce the energy barrier of the reaction process, while XPS analysis showed Co3+/Co2+ redox couple can accelerate PMS activation. Enhanced anode oxidation can effectively promote cathode reduction and consequently Co3O4‐Ov/TiO2‐PMS/PEC system presents a superior removal of both pollutants within only 15 min with fast kinetics (0.15 min−1 for BPA, 0.29 min−1 for Cr(VI)). This work provides unique insight into designing a highly efficient PMS/PEC system for simultaneous pollutant treatment.

Proflavine binding to La-Sr perovskite manganite nanoparticles at temperatures above and below the Сurie temperature

The magnetic properties of La1-xSrxMnO3 (LSMO) nanoparticles within the ferromagnetic region (x ≈ 0.2–0.5) enable their application in two types of cancer treatment: chemotherapy drug delivery and self-controlled hyperthermia. Single-phase La0.80Sr0.20MnO3 nanoparticles were prepared by the sol-gel process followed by mechanical processing. Sample characterization was performed by using XRD, TEM, EPR, and DLS techniques. The encapsulation efficiency of proflavine to the nanoparticles was determined via spectrophotometry. The mean size of crystallites of LSMO nanoparticles is 18 nm, and the Curie temperature is 319 K. Bare LSMO particles do not form a colloidally stable aqueous suspension; they exhibit a zeta potential close to zero and provide micro-sized aggregates. Application of sodium citrate for their stabilization leads to a decrease in the size of agglomerates and to a highly negative zeta potential of –33 mV. The efficiency of proflavine sorption by LSMO nanoparticles increases significantly above the Curie temperature, from 16.1 % at 298 K to 26.2 % at 333 K. This increase is attributed to the partial disruption of nanoparticle agglomerates in suspension after the LSMO phase loses its ferromagnetic order. In summary, heating LSMO nanoparticles above the Curie temperature increases the degree of drug loading on the nanoparticles.

Zinc Phthalocyanine Core-First Star Polymers Through Nitroxide Mediated Polymerization and Nitroxide Exchange Reaction.

Nitroxide-mediated polymerization (NMP) and nitroxide exchange reaction (NER) are very efficient methodologies that require only suitable alkoxyamine derivatives and create different polymeric architectures in a controlled manner. Herein, the synthesis of star polymers containing TEMPO-substituted symmetric zinc phthalocyanine (ZnPc) is presented via NMP and NER. Moreover, linear polymer formation is conducted in a single arm on TEMPO-substituted asymmetric ZnPc to elucidate the properties of star polymers. All linear and star polymers are characterized by FT-IR, UV-vis, fluorescence, GPC, NMR, and EPR techniques. The results show that the proposed reactions are capable of forming controlled star-shaped polymers. The increasing arm number (from a single to four arms) results in variable dispersity values (Đ) (1.2-3) due to different arm lengths, especially in NMP. However, this difficulty has been overcome via NER, and star polymers have been successfully synthesized with relatively low molecular weight (30 K > 10 K) and low dispersity (1.2-1.9). The results clearly indicate that while styrene and 4-vinyl benzyl chloride monomers are introduced to the structure equally, star polymers with phthalocyanine can be synthesized in a controlled manner, and their quarternized derivatives have the potential to be effective as photoactive agents in photodynamic therapy.

Microwave field mapping for EPR-on-a-chip experiments.

Electron paramagnetic resonance-on-a-chip (EPRoC) devices use small voltage-controlled oscillators (VCOs) for both the excitation and detection of the EPR signal, allowing access to unique sample environments by lifting the restrictions imposed by resonator-based EPR techniques. EPRoC devices have been successfully used at multiple frequencies (7 to 360 gigahertz) and have demonstrated their utility in producing high-resolution spectra in a variety of spin centers. To enable quantitative measurements using EPRoC devices, the spatial distribution of the B1 field produced by the VCOs must be known. As an example, the field distribution of a 12-coil VCO array EPRoC operating at 14 gigahertz is described in this study. The frequency modulation-recorded EPR spectra of a "point"-like and a thin-film sample were investigated while varying the position of both samples in three directions. The results were compared to COMSOL simulations of the B1-field intensity. The EPRoC array sensitive volume was determined to be ~19 nanoliters. Implications for possible EPR applications are discussed.

An Air-Stable Carbon-Centered Triradical with a Well-Addressable Quartet Ground State.

Organic polyradicals with a high-spin ground state and quantum magnetic properties suitable for spin manipulation are valuable materials for diverse innovative technologies, including quantum devices. However, the typically high reactivity and low stability of conventional polyradicals present a major obstacle to such applications. In this study, a highly stable carbon-centered triradical TR with a quartet ground state and excellent stability (τ1/2 of ∼90 days in air-saturated toluene at room temperature) is achieved, which shows apposite magnetic anisotropy and Zeeman splitting partition with favorable addressability. By virtue of the optimal stability, thorough structural and magnetic characterizations are realized. With X-ray crystallography unambiguously proving the molecular structure, the quartet ground state (ΔED-Q = 0.78 kcal/mol) is confirmed by the SQUID measurements, while the cw- and pulsed EPR techniques offer additional supportive evidence for the high-spin nature. Remarkably, owing to the easily attained magnetic anisotropy, selective excitations between different Zeeman splitting levels are successfully demonstrated with TR in its frozen toluene solution without the requirement for special alignment, which is unprecedented for organic polyradicals. Along with the millisecond spin-lattice relaxation and microsecond coherence time manifested by TR, this triradical is promising for potential coherent spin manipulation applications as a multienergy-level quantum information carrier.

Controlling the optical output of arylamino-dibenzothiophene systems by sulphur oxidation state

Six arylamino-dibenzothiophene (Ary-DBTs) derivatives (with D-π-D or D-π pattern) were synthesized in order to investigate how the symmetry and different oxidation states, sulfide (Ary-DBT, Ary2-DBT), sulfoxide (Ary-DBTSO, Ary2-DBTSO) and sulfone (Ary-DBTSO2, Ary2-DBTSO2) affect the optical properties of these compounds, respectively. To unravel the complexity of their photophysics, extensive characterization was carried out, including UV–Vis and fluorescence spectroscopy both in different solvents at room temperature and in rigid matrix at 77 K. In addition to the presence of various singlet states, this study has brought to light the existence, in rigid conditions, of radiative triplet states responsible for phosphorescence phenomena. This interesting architecture of triplet states was investigated using the time-resolved EPR (TREPR) technique and further supported by TDDFT calculations. This approach allows us to obtain a complete photophysical view of the generation and decay of excited states and how molecular geometry influences it.

Spectroscopic properties and luminescence of the lithium tetraborate glasses co-doped with manganese and europium

High quality Li2B4O7:Mn,Eu glasses containing 1.0 mol.% MnO2 and Eu2O3 were prepared and investigated by XRD, EPR and optical spectroscopy techniques. Obtained data analysis shows that Mn is incorporated into the glass network as Mn2+ and Mn3+. Parameters of observed Mn2+ EPR signals in the Li2B4O7:Mn,Eu glasses were determined. Optical absorption spectrum of the studied glasses consists of broad band at 464 nm corresponding to the 5Eg(D) → 5T2g(D) transition of Mn3+ (3d4) ions and few narrow weak bands of the Eu3+ (4f6) ions. Emission spectra of the Li2B4O7:Mn,Eu glasses in orange-red region exhibit several sharp bands corresponding to the 5D0 → 7FJ (J = 0–4) transitions of Eu3+ ions and broad band belonging to the 4T1g(G) → 6A1g(S) transition of Mn2+ (3d5) ions. Comparative discussions were made on the luminescence spectra and decay curves of Mn2+ and Eu3+ ions in the Li2B4O7:Mn,Eu glasses and those in Mn-doped and Eu-doped glasses with the Li2B4O7 basic composition.

Construction of BiVO4@ NiCo2O3 heterojunction to promote photocatalytic CO2 reduction

Constructing a catalyst capable of reducing CO2 through photoreduction in aqueous environments presents a significant challenge. In this study, we present the synthesis of BiVO4@NiCo2O3 heterojunction using a straightforward hydrothermal method for CO2 photoreduction. The sample with the optimal loading ratio demonstrates a CO generation rate of 7.202 μmol·g‐1·h‐1, which is twice that of pristine BiVO4 (3.626 μmol·g‐1·h‐1) and 1.5 times that of pure NiCo2O3 (4.726 μmol·g‐1·h‐1). Analysis using XPS and EPR techniques suggests that electron transfer at the interface of the heterojunction facilitates the separation of photogenerated charge carriers, thereby enhancing the efficiency of the photocatalytic process. This investigation offers a viable approach for developing photocatalysts for CO2 reduction in aqueous environments.

A combined experimental and computational study of ligand-controlled Chan-Lam coupling of sulfenamides

The unique features of the sulfenamides’ S(II)-N bond lead to interesting stereochemical properties and significant industrial functions. Here we present a chemoselective Chan–Lam coupling of sulfenamides to prepare N-arylated sulfenamides. A tridentate pybox ligand governs the chemoselectivity favoring C–N bond formation, and overrides the competitive C-S bond formation by preventing the S,N-bis-chelation of sulfenamides to copper center. The Cu(II)-derived resting state of catalyst is captured by UV-Vis spectra and EPR technique, and the key intermediate is confirmed by the EPR isotope response using 15N-labeled sulfenamide. A computational mechanistic study reveals that N-arylation is both kinetically and thermodynamically favorable, with deprotonation of the sulfenamide nitrogen atom occurring prior to reductive elimination. The origin of ligand-controlled chemoselectivity is explored, with the interaction between the pybox ligand and the sulfenamide substrate controlling the energy of the S-arylation and the corresponding product distribution, in agreement with the EPR studies and kinetic results.

Crystal structures and photoluminescence properties of undoped and Fe3+ doped Li2Ba3(P2O7)2 pyrophosphate nanopowders

Undoped and Fe3+ doped Li2Ba3(P2O7)2 pyrophosphate nanopowders were produced by a solid-state reaction process. The prepared samples underwent characterizations using XRD, SEM with EDS, HR-TEM with SAED, FTIR, Raman, UV-Vis, EPR and PL techniques. The XRD analysis confirms the orthorhombic crystal structure of the prepared samples and unit cell parameters were evaluated. The samples exhibited stone-like structures with low aggregation based on the micrographs obtained from SEM and HR-TEM images. Additionally, the grain and particle sizes of the powder samples were evaluated. The elements Li, O, P, Ba and Fe were confirmed to be present in the produced samples by EDS spectra. FT-IR and Raman spectral investigation revealed the fundamental vibrational and bending modes of various phosphate groups. The energy bands, identified as characteristic bands of Fe3+ ions, were produced in the UV–visible region of the optical absorption spectrum for the doped sample. The crystal field and inter-electronic parameters (Dq = 915, B = 700 and C = 2715 cm−1) were also evaluated. Furthermore, the refractive index and metallization criteria properties were calculated using energy bandgap values of 4.46 and 4.38 eV of the produced samples. The doping of Fe3+ ions led to a reduction in the bandgap energy, resulting in a red-shift. A resonance signal was observed in the EPR spectrum at g = 2.05, which can be ascribed to iron ions entering the host lattice at a distorted octahedral symmetry sites and this was also supported by optical absorption studies. The produced sample showed emission peaks at 354, 440 and 530 nm in the ultraviolet, blue and green regions of its photoluminescence spectrum. Photometric parameters, such as CCT, CRI and CIE chromatic coordinates, reveal that the prepared samples could bee used in LEDs applications. This work offers novel visions into diphosphate compounds doped with transition metal ions.

MOF-818(Cu)-derived bi-nanozymes of laccase and catecholase mimics and colorimetric sensing to epinephrine

Cu-based nanozyme shows good oxidase-like activities due to the changeable states of Cu(II) and Cu(I), which are proven to be effective in the electron transfer in the redox process. Herein, the self-made MOF-818 with more Cu(II) loading was synthesized through a modified two-steps hydrothermal routes, which was then used as a sacrificial precursor to construct copper/zirconium composite oxides nanozymes (CN-MOF-818). The pyrolysis temperature was varied to obtain the best enzyme-like activities of the resulting CN-MOF-818. The laccase-like and catecholase-like activities were evaluated by using the oxidation of the mixture of 4-aminoantipyrine (4-AAP) and 2,4-dichlorophenol (2,4-DP), and 3,5-Di-tert-butylcatechol (3,5-DTBC) respectively. The enzyme-like activities were optimized through altering the catalytic conditions, and the corresponding enzyme catalytic kinetics including Km and Vmax were also determined. The enzyme-like mechanism of the CN-MOF-818 were also discussed based on EPR technique and the in-situ FT-IR analyses. In comparison with the pristine MOF-818 and the other reported Cu-based mimics, the as-prepared CN-MOF-818 exhibits the higher oxidase mimetic activities. These CN-MOF-818 can also be employed to detect the epinephrine with a low detection limit of 1.63 μM.

Regioselective Rearrangement of Nitrogen- and Carbon-Centered Radical Intermediates in the Hofmann-Löffler-Freytag Reaction.

The Hofmann-Löffler-Freytag (HLF) reaction serves as a late-stage functionalization technique for generating pyrrolidine heterocyclic ring systems. Contemporary HLF protocols utilize in situ halogenated sulfonamides as precursors in the radical-mediated rearrangement cycle. Despite its well-established reaction mechanism, experiments toward the detection of radical intermediates using EPR techniques have only recently been attempted. However, the obtained spectra lack the distinct features of the N-centered radicals expected for the employed reactants. This paper presents phenylbutylnitrone spin-trapped C-centered and N-centered radicals, generated via light irradiation from N-halogen-tosyl-sulfonamide derivatives and detected using EPR spectroscopy. NMR spectroscopy and DFT calculations are used to explain the observed regioselectivity of the HLF reaction.

Activation of peroxymonosulfate by LaCO3OH coupled with N, S co-doped graphene for levofloxacin degradation

There is currently great potential in peroxymonosulfate (PMS) activation by metal-based materials for contaminant treatment. However, secondary environmental damage from common transition metals is often unavoidable. Rare earth metals with high energy level, multi-electron configuration and unique 4f orbital can be used as an electron transfer bridge to reduce interfacial energy loss and promote electron transfer, which were incorporated the catalyst to activate PMS. In this study, calcination and hydrothermal methods were combined to fabricate LaCO3OH in combination with N, S co-doped graphene (LCOH/GNS), which exhibited efficient levofloxacin (LVX) degradation. The results indicated that the LVX removal efficiency reached 89.6 %, and the La3+ leaching was as low as 1.2 mg/L. LaCO3OH (LCOH) was first used for PMS activation and showed excellent degradation properties and reduced ecotoxicity. Doping the graphene matrix with N and S enhances the adsorption of PMS, increases electron transfer and reduces leaching of metal ions, thus promoting the interaction and reaction between LCOH and PMS. As confirmed by radical quenching tests and EPR technique, multiple oxidative pathways may be involved in the degradation process. This paper presented an innovative approach to the rational design of rare earth metal-based carbon catalysts, and it was expected that LCOH/GNS-PMS would prove to be a promising technology for degrading antibiotics in wastewater treatment.

Photoinduced Selective B-H Activation of nido-Carboranes.

The development of new synthetic methods for B-H bond activation has been an important research area in boron cluster chemistry, which may provide opportunities to broaden the application scope of boron clusters. Herein, we present a new reaction strategy for the direct site-selective B-H functionalization of nido-carboranes initiated by photoinduced cage activation via a noncovalent cage···π interaction. As a result, the nido-carborane cage radical is generated through a single electron transfer from the 3D nido-carborane cage to a 2D photocatalyst upon irradiation with green light. The resulting transient nido-carborane cage radical could be directly probed by an advanced time-resolved EPR technique. In air, the subsequent transformations of the active nido-carborane cage radical have led to efficient and selective B-N, B-S, and B-Se couplings in the presence of N-heterocycles, imines, thioethers, thioamides, and selenium ethers. This protocol also facilitates both the late-stage modification of drugs and the synthesis of nido-carborane-based drug candidates for boron neutron capture therapy (BNCT).

Defect-synergetic effect enhanced CO2 photoreduction efficiency of TiO2 nanostructures with Fe dopants

TiO2 nanostructures (NSs) doped with varying Fe concentrations are synthesized using the sol-gel process, followed by annealing in 1 atm environment at 470 ℃ for 3 h. Anatase TiO2 crystal structure and defect levels are characterized using XRD, HRTEM, SEM-EDS, XPS, Raman, EPR, PL, and TR-PL techniques. Remarkably, the addition of approximately 4 wt% Fe dopant had no discernible impact on the crystal structure of the anatase TiO2. Furthermore, energy levels including VO, Tii∙∙∙, Fe3+/Fe2+, Fe3+/Fe4+, and Ti3+/Ti4+ are identified. The optical band-gap of TiO2 is reduced from 3.077 to 2.352 eV and its carrier lifetime is extended from 6.53 ns to 9.12 ns with Fe contents ranging from 0 to approximately 2 wt%. The CO2 photoreduction results demonstrate that Fe-doped TiO2 outperforms commercial TiO2 (P25) in terms of the photoreduction rate. Particularly, TiO2 NSs doped with 2 wt% Fe exhibit the highest CO2 photoreduction rates, yielding approximately 35.19×102 and 66.84×102 μmol‧g1‧min1of CO and CH4, respectively; thereby surpassing P25 by factors of 1.26 and 3.1, respectively. Therefore, Fe-doping can reduce the optical band-gap and extend the carrier lifetime of TiO2 photocatalysts, resulting in superior CO2 photoreduction capabilities. Moreover, the significance of electrons in the CO2 photoreduction process, as evidenced by the findings from the EPR spectrum and CO2 photoreduction, underscores the importance of an appropriate Fe content, such as 2 wt% used in this study, for enhancing the photoreduction abilities and potential applications of TiO2 in CO2 photoreduction.

How Does Radiation Affect Curcumin Raw Material?

Turmeric, known for its curcuminoid-rich rhizome, particularly curcumin, exhibits notable antioxidant and antiviral properties. The likelihood of microbial contamination necessitates finding reliable techniques for subjecting the sample to radiation from this plant-based raw material. One alternative is to expose curcumin to radiation (e-beam), which was carried out as part of this research. Confirmation of the lack of curcumin decomposition was carried out using HPLC-DAD/MS techniques. Additionally, using the EPR technique, the generated free radicals were defined as radiation effects. Using a number of methods to assess the ability to scavenge free radicals (DPPH, ABTS, CUPRAC, and FRAP), a slight decrease in the activity of curcumin raw material was determined. The analysis of the characteristic bands in the FT-IR spectra allowed us to indicate changes in the phenolic OH groups as an effect of the presence of radicals formed.

New Features of Laboratory-Generated EPFRs from 1,2-Dichlorobenzene (DCB) and 2-Monochlorophenol (MCP).

The present research is primarily focused on investigating the characteristics of environmentally persistent free radicals (EPFRs) generated from commonly recognized aromatic precursors, namely, 1,2-dichlorobenzene (DCB) and 2-monochlorophenol (MCP), within controlled laboratory conditions at a temperature of 230 °C, termed as DCB230 and MCP230 EPFRs, respectively. An intriguing observation has emerged during the creation of EPFRs from MCP and DCB utilizing a catalyst 5% CuO/SiO2, which was prepared through various methods. A previously proposed mechanism, advanced by Dellinger and colleagues (a conventional model), postulated a positive correlation between the degree of hydroxylation on the catalyst's surface (higher hydroxylated, HH and less hydroxylated, LH) and the anticipated EPFR yields. In the present study, this correlation was specifically confirmed for the DCB precursor. Particularly, it was observed that increasing the degree of hydroxylation at the catalyst's surface resulted in a greater yield of EPFRs for DCB230. The unexpected finding was the indifferent behavior of MCP230 EPFRs to the surface morphology of the catalyst, i.e., no matter whether copper oxide nanoparticles are distributed densely, sparsely, or completely agglomerated. The yields of MCP230 EPFRs remained consistent regardless of the catalyst type or preparation protocol. Although current experimental results confirm the early model for the generation of DCB EPFRs (i.e., the higher the hydroxylation is, the higher the yield of EPFRs), it is of utmost importance to closely explore the heterogeneous alternative mechanism(s) responsible for generating MCP230 EPFRs, which may run parallel to the conventional model. In this study, detailed spectral analysis was conducted using the EPR technique to examine the nature of DCB230 EPFRs and the aging phenomenon of DCB230 EPFRs while they exist as surface-bound o-semiquinone radicals (o-SQ) on copper sites. Various aspects concerning bound radicals were explored, including the hydrogen-bonding tendencies of o-semiquinone (o-SQ) radicals, the potential reversibility of hydroxylation processes occurring on the catalyst's surface, and the analysis of selected EPR spectra using EasySpin MATLAB. Furthermore, alternative routes for EPFR generation were thoroughly discussed and compared with the conventional model.

Enhanced photocatalytic CO2 conversion of a CdS/Co-BDC nanocomposite via Co(ii)/Co(iii) redox cycling.

Photocatalytic CO2 reduction into value-added chemical fuels using sunlight as the energy input has been a thorny, challenging and long-term project in the environment/energy fields because of to its low efficiency. Herein, a series of CdS/Co-BDC composite photocatalysts were constructed by incorporating CdS nanoparticles into Co-BDC using a dual-solvent in situ growth strategy for improving photocatalytic CO2 reduction efficiency. The composites were characterized through XRD, SEM, TEM, XPS, DRS and EPR techniques in detail. 18% CdS/Co-BDC composites showed superior performance for the photocatalytic CO2 reduction to CO, which was 8.9 and 19.6 times higher than that showed by the pure CdS and Co-BDC, respectively. The mechanism of enhanced photocatalytic CO2 reduction performance was analyzed. The CdS/Co-BDC composites showed better adsorption for CO2. Detailed analysis of XPS, transient photocurrent responses, and electrochemical impedance spectroscopy (EIS) shows the existence of strong charge interaction between CdS and Co-BDC and the photo-electrons of CdS can be transferred to Co-BDC. Additionally, Co-oxo of Co-BDC plays the role of a redox-active site and promotes the reduction performance via the method of valence transition of Co(ii)/Co(iii) redox.

Catalytic combustion of toluene over cerium modified CuMn/Al2O3/cordierite monolithic catalyst

Catalytic combustion is an effective approach to remove volatile organic compounds, in which the development of highly active and durable catalyst is extremely crucial. Herein, a series of CuMnCex/Al2O3/cordierite monolithic catalysts were synthesized by using the ultrasonic-assisted impregnation method. The physicochemical properties were comprehensively characterized via the BET, XRD, SEM, EDX, H2-TPR, O2-TPD, XPS and EPR techniques. The results showed that the catalytic activity of CuMnCex/Al2O3/Cor for toluene combustion was strongly affected by the Ce content. The CuMnCe2/Al2O3/Cor monolithic catalyst showed the best catalytic activity with toluene conversion of 90% at 263 °C under toluene concentration of 1 g/L and space velocity of 78000 mL/(g·h). Meanwhile, the well-dispersed CeO2 in the CuMn matrix not only improved the content of oxygen vacancies and the mobility of oxygen species, but also enhanced the low-temperature reducibility of the catalyst. Moreover, the CuMnCe2/Al2O3/Cor monolithic catalyst exhibited an excellent stability in the long-term test and cycle ability test.