Surface Oxygen Vacancy Concentration Research Articles

Enhanced activity and stability of Sr2FeMo0.65Ni0.35O6-δ anode for solid oxide fuel cells with Na doping

Sr2-xNaxFeMo0.65Ni0.35O6-δ is synthesized as an anode material for solid oxide fuel cells. The effects of Na on the crystalline phase and electrical properties are investigated. The main perovskite phase changes into a Ruddlesden-Popper structure after reduction when x is less than 0.1, while the material with a higher amount of Na keeps the perovskite structure. FeNix alloy nanoparticles are exsolved during reduction, in which the content of Ni increases with the rise of Na amount. The surface oxygen vacancy concentration is also influenced by the doping of Na, and the highest value is reached when x is 0.1. Sr1.9Na0.1FeMo0.65Ni0.35O6-δ anode exhibits the highest activity, and a single cell supported by a 300-μm-thick La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte layer shows maximum power densities of 1495 and 627 mW cm−2 at 850 °C with H2 and wet CH4 as fuels, respectively. The coking resistance of the anode is also improved with Na doping.

Oxygen vacancy modulation of commercial SnO2 by an organometallic chemistry-assisted strategy for boosting acetone sensing performances

Oxygen vacancies play a critical role in the sensing performances for metal oxides-based chemiresistor-type sensors. Developing facile and effective strategies for fabricating metal oxides with controllable oxygen vacancies is in great demand but remains paramount challenge. Herein, a novel organometallic chemistry-assisted method is reported to prepare SnO2 samples containing controllable surface oxygen vacancies. This new approach combines modification of SnO2 with dimethyltin dichloride, and subsequently thermal treatment in air atmosphere. Taking commercial SnO2 as an example, it is found that the optimized SnO2 sample possesses highest surface oxygen vacancy concentration of 37.13%. Owing to increased oxygen vacancy concentration, the resulting SnO2 sample (SnO2-Sn-0.5) presents excellent sensing performances for detection of acetone, including high response, fast response and recovery rate, good selectivity, compared with pristine SnO2 with low oxygen vacancy concentration (28.66%). This work paves a new avenue for fabricating metal oxides with controllable oxygen vacancies for various applications of sensing, energy storage, and so on.

Tailoring the room temperature ferromagnetism in TiO2 nanoparticles by modulating the concentration of surface oxygen vacancy via La incorporating

Abstract La-incorporated TiO2 nanoparticles (Ti1-xLaxO2) were synthesized by a sol-gel method followed by vacuum annealing at 500 °C for 4 h, and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman scattering spectroscopy, and vibrating sample magnetometer (VSM), respectively. The results indicated that La ions were incorporated with TiO2 without distorting the tetragonal anatase structure, and a small amount of La ions were doped into TiO2 lattice by substituting the surface Ti sites, whereas most of the La atoms evenly distribute into TiO2 matrix in the form of La2O3. The incorporation of La ions with TiO2 matrix modulates the concentration of surface oxygen vacancy in Ti1-xLaxO2 nanoparticles. The room temperature ferromagnetism (RTFM) in Ti1-xLaxO2 nanoparticles varies with the concentration of surface oxygen vacancy due to ferromagnetic coupling interactions between singly ionized oxygen vacancy, thus RTFM can be tailored by modulating the concentration of surface oxygen vacancy via La ions incorporating.

Promotion of surface oxygen vacancies on the light olefins synthesis from catalytic CO2 hydrogenation over Fe[sbnd]K/ZrO2 catalysts

The performance of K and Fe loaded ZrO2 species (FeK/ZrO2) for CO2 hydrogenation was relevant to the concentration of oxygen vacancies due to the differences of ZrO2 crystal phases. The K and Fe were deposited on the surface of monoclinic zirconia (m-ZrO2) and tetragonal zirconia (t-ZrO2) with the Fe loading of 0–20 wt% and the K loading of 1 wt% by impregnation methods. The ZrO2 served as both a support and a co-catalyst for CO2 hydrogenation, exhibiting 40.54% CO2 conversion and 14.98% light olefins selectivity over the 10Fe1K/m-ZrO2 with 10 wt% Fe and 1 wt% K, at 2.0 MPa and 340 °C. Such CO2 conversion were almost 200% higher than that of 10Fe1K/t-ZrO2. The better activity of 10Fe1K/m-ZrO2 is mainly attributed to the higher concentration of oxygen vacancies on the surface of m-ZrO2 after the reduction in H2/N2. However, covering the surface of m-ZrO2, excess surface Fe species lowered the concentration of surface oxygen vacancies for reduced 10Fe1K/t-ZrO2, which inhibited the catalytic performance of ZrO2 for CO2 conversion. These investigations may propel the utilization of Zr-based catalysts on CO2 hydrogenation to various value-added chemicals.

Structure and crystal phase transition effect of Sn doping on anatase TiO2 for dichloromethane decomposition.

Efficient removal of chlorinated volatile organic compounds (CVOCs) has received great attention because of the considerable harm that they cause to the environment and to human health. Developing novel catalysts and exploring the catalytic activation and deconstruction mechanism of CVOCs molecule are always the focus in this field. Here, a set of Sn doped TiO2 catalysts were investigated for the decomposition of dichloromethane (DCM). Rietveld refinement of the XRD patterns showed that Sn ions can uniformly disperse into TiO2 and induce the crystal transition of anatase. Meanwhile, such decorating can induce an increase in specific surface area and affect the surface oxygen vacancy concentration of these samples, which have been demonstrated by N2 adsorption and XPS, respectively. Catalytic performance tests indicated that the Sn0.2Ti0.8O2 has the best activity for DCM decomposition, and a lower CH3Cl selectivity than that of pure TiO2. Computational results suggested the dominant surface (110) of rutile Sn0.2Ti0.8O2 is more beneficial for the adsorption/dissociation of DCM molecule than that of anatase TiO2 (101). That's because the anchoring of DCM to Sn sites and electron enrichment on the surface bridge oxygen atoms of rutile Sn0.2Ti0.8O2 (110) can promote the nucleophilic substitution process for breaking of CCl bonds.

Effect of surface and bulk palladium doping on the catalytic activity of La2Sn2O7 pyrochlore oxides for diesel soot oxidation

The soot combustion on Pd-doped La2Sn2O7 pyrochlore oxides was studied. Palladium promoter was doped into the pyrochlore system via two ways: bulk substitution (La2Sn1.9Pd0.1O7) and surface impregnation (Pd/La2Sn2O7). The catalysts were characterized by XRD, BET, SEM, HRTEM, PL, XPS and H2-TPR measurements. Pd modifications increased the concentration of surface oxygen vacancy, especially Pd/La2Sn2O7. The different morphologies of palladium promoters were revealed in the two palladium-doped catalysts. Palladium was present primarily in the form of a lattice Pd2+ in the bulk-doping sample, with trace of metal palladium deposited on the surface. As for the surface-doping sample, PdO was the predominant form, accompanied with some of highly dispersed metallic palladium. Due to the adhesion of massive surface palladium species on Pd/La2Sn2O7, a strong metal oxide interaction occurred in the interface between Pd species and La2Sn2O7. The activity evaluation results show that Pd/La2Sn2O7 possesses the highest performance, exhibiting the lowest activation energy (98.83 kJ/mol) for soot combustion. Surface Pd/PdO redox couples as well as Pd–O–Sn interface species were identified to be the active phases for the superior catalytic behavior of Pd/La2Sn2O7. A possible oxidation mechanism for the reactions has been speculated.

Upgrading of vacuum residue with chemical looping partial oxidation over Ce doped Fe2O3

Partial oxidation provides a promising method for upgrading of heavy oil. In this study, a series of Ce doped Fe2O3 materials were prepared and applied for partial oxidation of vacuum residue. The effect of Ce doping on the physicochemical properties of Fe2O3 was recognized through a series of characterization techniques. Some Fe in Fe2O3 structure were substituted by Ce to form solid solution, resulting in increase of specific surface area and oxygen vacancy concentration. The partial oxidation of vacuum residue showed that Ce doping to Fe2O3 could increase the heavy oil conversion, yields of gasoline and diesel, which are attributed to the large specific surface area and increased oxygen vacancy concentration. Based on the partial oxidation performance of Ce doped Fe2O3, a chemical looping for upgrading of vacuum residue using FeCe-1 as oxygen carrier was proposed. The heavy oil conversion, yield of gasoline and diesel remain stable under chemical looping process.

Influence of preparation method and doping of zirconium oxide onto the material characteristics and catalytic activity for the HDO reaction in nickel on zirconium oxide catalysts

Different Ni/ZrO2 catalysts were prepared and tested for the hydrodeoxygenation (HDO) reaction of guaiacol. It was shown that the preparation mode of the ZrO2 support has a significant influence on the catalytic results, as remaining elements like Si and Na from the preparation can change the material properties. The influence of Si and Na onto these material properties, which were especially surface acidity and oxygen vacancy concentration, could be clarified. It could be also rationalized, how the change of these properties affects the results of the HDO reaction. Furthermore, it was demonstrated that the oxygen vacancy concentration is an important factor for the catalytic performance, although this property has hardly been considered in the design of HDO catalysts so far. La doping was found to be an efficient strategy to tune the oxygen vacancy concentration, and by using this approach the catalytic performance of the catalyst could be improved remarkably.

A novel anode for solid oxide fuel cells prepared from phase conversion of La0.3Sr0.7Fe0.7Cr0.3O3-δ perovskite under humid hydrogen

A novel anode for solid oxide fuel cells (SOFCs), consisting of a Ruddlesden-Popper compound, La0.6Sr1.4Fe0.4Cr0.6O3.8, with in situ exsolved α-Fe nanoparticles (RP-LSF + Fe), is prepared from the phase conversion of the La0.3Sr0.7Fe0.7Cr0.3O3-δ (LSFCr-3) perovskite under humid H2 at 800 °C. On the surface of the RP-LSF + Fe anode, Fe cations are presented to be a mixture of Fe2+ and Fe3+, of which the average valence is lower than that in the bulk (Fe3+). The coverage of atomic hydrogen on the RP-LSF + Fe anode is over 0.8 in the pH2 range of 0.017–0.27 atm, implying a significant effect of these small amount (∼8 mol% on the surface) of exsolved Fe nanoparticles (∼200–300 nm) on promoting the dissociative absorption of H2. The charge transfer resistance is found to be closely related to the concentration of surface oxygen vacancies of the oxide matrix. The addition of catalytic amount of Ni (1–3 wt.%) greatly improves the fuel flexibility of the RP-LSF + Fe anode. Furthermore, it contributes to acceleration the phase conversion of the LSFCr-3 perovskite and reduced time for in situ preparation of the RP-LSF + Fe anode. The RP-LSF + Fe anode with 2.7 wt.% Ni exhibits a stable cell performance under 2.7%H2O+1:1-(H2:CO) and 2.7%H2O + CH4 for ∼30 h. It costs shortest time (30 h) to reach a stable cell voltage of 0.76 V at a galvanostatic current density of 0.25 A/cm2 under humid H2, which is clearly an active and stable anode material for SOFCs.

Template‐free Scalable Synthesis of Flower‐like Co3‐xMnxO4 Spinel Catalysts for Toluene Oxidation

AbstractThe rational design of low‐cost transition metal catalysts that exhibit high activity and selectivity may be the most significantly investigated in heterogeneous catalysis. In this study, Co3‐xMnxO4 (x=0.75, 1.0, and 1.5) mixed metal oxides were successfully synthesized by a controlled template‐free autoclave strategy and studied for toluene oxidation. It is found that the Co‐rich sample showed markedly enhanced activity and the 3D dandelion‐like Co2.25Mn0.75O4 catalyst exhibited in the highest toluene oxidation rate (8.9 μmol/(gcats)) and a 100 % toluene conversion at 239 °C. In situ DRIFTS study indicates that toluene was sequentially oxidized to benzyl radical, benzaldehyde, benzene, oxalic acid, and finally to CO2 and H2O. The interaction between Co and Mn, in conjunction with the high concentration of surface oxygen species and rich surface oxygen vacancies, reasonably explains the elevated catalytic activity and thermal stability for toluene oxidation over 3D flower‐like Co3‐xMnxO4 spinel catalysts.

Ceria-samarium binary metal oxides: A comparative approach towards structural properties and soot oxidation activity

Binary metal oxides of CeO2-Sm2O3 (CSx, x varies from 10 to 90 mol%) along with pure CeO2 and Sm2O3 were synthesised successfully by the EDTA-Citrate method. From XRD, Raman spectroscopy and UV–vis DRS results, the whole composition of metal oxides exist in three phases: (fluorite phase (F) (CS10-CS30), bi-phase (fluorite (F) + cubic (C)) (CS30-CS90) and cubic phase (C) (Sm2O3)). For CSx samples, the calculated band gap energy values obtained from the UV–vis DRS results were in between 3.0–5.1 eV and fluorite phase samples (CS10–CS30) displayed lower band gap energy values (3.04–3.07 eV) than compared to the samples in other phases. Similarly, from XPS analysis, fluorite phase samples (CS10–CS30) showed higher surface oxygen vacancy concentration than compared to samples in other phases. Catalytic activity for soot oxidation is carried out on CSx samples, and the T50 temperature is in between 480–540 °C. Fluorite phase samples (CS10 CS30) showed higher surface area, lower degree of agglomeration, lower band gap energy, higher oxygen vacancy concentration and better catalytic activity for soot oxidation. Among all the CSx samples, CS10 sample displayed highest surface area (38 m2/g), lowest degree of agglomeration (0.36), lowest band gap energy (3.04 eV), highest oxygen vacancy concentration (64%) and highest soot oxidation activity (T50 = 480 °C). The order of the soot oxidation activity of CSx samples followed the same trend of band gap energy values.

Simple fabrication ZnO/β-Ga2O3 core/shell nanorod arrays and their photoresponse properties

In this paper, a facile and cost effective hydrothermal method was employed to fabricate high performance ZnO/β-Ga2O3 core-shell heterostructures. A highly sensitive ultraviolet (UV) sensor was fabricated based on vertically aligned β-Ga2O3 decorated ZnO core-shell nanorod arrays (NRs). The ZnO/β-Ga2O3 heterostructures showed an excellent improvement in UV response characteristics comparing with bare ZnO NRs. It can be attributed to the lower interface barrier and larger surface area-to-volume ratio for the ZnO/β-Ga2O3 heterostructures. Meanwhile, a higher concentration of surface oxygen vacancies has been observed in ZnO/β-Ga2O3 heterostructures, which helps to increase the charge separation efficiency for the UV detector. The results suggested that the ZnO/β-Ga2O3 core-shell heterostructure should be suitable for practical applications of UV photodetectors.

Effect of rare earth (RE – La, Pr, Nd) metal-doped ceria nanoparticles on catalytic hydrogen iodide decomposition for hydrogen production

In this work, high surface area rare earth (RE = La, Pr, and Nd) metal-doped ceria (CeO2) nanocatalysts have been synthesized by the citric-aided sol-gel method for hydrogen-iodide decomposition in thermochemical water-splitting sulfur-iodine (SI) cycle for hydrogen production. This sol-gel method allows the insertion of rare earth metal M3+ ions into the CeO2 material. Incorporation of rare earth metals created a different synergistic effect between RE and Ce components such as increase of oxygen mobility, oxygen vacancy, and thermal stability of the CeO2 material. These doped-CeO2 materials were characterized by various physicochemical techniques, namely, XRD, BET, ICP-AES, TEM, TGA, and RAMAN spectroscopy. XRD and TEM studies revealed 5–10 nm particles of the RE-CeO2 material. Shifting of peaks and increase in lattice parameter values confirmed the formation of Ce-RE solid solutions (XRD and Raman). Incorporation of dopants resulted in an increase in the specific surface area (BET), thermal stability (TGA), and oxygen vacancy concentration (Raman). Among different dopants, CeO2-L (La-doped CeO2) material exhibits the highest specific surface area, thermal stability, and oxygen vacancy concentration, and smallest crystallite size. The catalytic activity of doped-CeO2 materials is explored for hydrogen-iodide decomposition. The order of catalytic activity is as follows: CeO2 < CeO2-N (N = Nd) < CeO2-P (P = Pr) < CeO2-L (L = La). CeO2-L shows higher catalytic activity and stability in comparison to the pure CeO2 material. It also showed an excellent time-on-stream stability for 35 h. The apparent activation energy of CeO2-L, CeO2-P, and CeO2-N was found to be 48.9, 54.8, and 61.4 kJ mol−1, respectively. The effect of iodine on hydrogen iodide conversion was also studied over a CeO2-L catalyst. Thus, RE-doped CeO2 catalysts show a lot of potential of generating hydrogen from hydrogen iodide in the SI cycle.

Low temperature CO oxidation catalysed by flower-like Ni-Co-O: how physicochemical properties influence catalytic performance.

In this work, mesoporous Ni–Co composite oxides were synthesized by a facile liquid-precipitation method without the addition of surfactant, and their ability to catalyse a low temperature CO oxidation reaction was investigated. To explore the effect of the synergetic interaction between Ni and Co on the physicochemical properties and catalytic performance of these catalysts, the as-prepared samples were characterized using XRF, XRD, LRS, N2-physisorption (BET), SEM, TEM, XPS, H2-TPR, O2-TPD and in situ DRIFTS characterization techniques. The results are as follows: (1) the doping of cobalt can reduces the size of NiO, thus massive amorphous NiO have formed and highly dispersed on the catalyst surface, resulting in the formation of abundant surface Ni2+ ions; (2) Ni2+ ions partially substitute Co3+ ions to form a Ni–Co spinel solid solution, generating an abundance of surface oxygen vacancies, which are vital for CO oxidation; (3) the Ni0.8Co0.2 catalyst exhibits the highest catalytic activity and a satisfactory stability for CO oxidation, whereas a larger cobalt content results in a decrease in activity, suggesting that the amorphous NiO phase is the dominant active phase instead of Co3O4 for CO oxidation; (4) the introduction of Co can alter the morphology of catalyst from plate-like to flower-like and then to dense granules. This morphological variation is related to the textural properties and catalytic performance of the catalysts. Lastly, a possible mechanism for CO oxidation reaction is tentatively proposed.

Dynamic surface composition in a Mars-van Krevelen type reaction: CO oxidation on Au/TiO2

Aiming at a better mechanistic understanding of Mars-van Krevelen type catalytic reactions, we have systematically investigated possible correlations between the composition of the reaction gas atmosphere, the concentration of surface oxygen vacancies (surface oxidation state), and the catalytic activity of a Au/TiO2 catalyst in the CO oxidation reaction. In the meantime, there is considerable experimental and theoretical evidence that this reaction follows a Au-assisted Mars-van Krevelen mechanism at reaction temperatures ≥80 °C. Employing quantitative pulse experiments in a temporal analysis of products (TAP) reactor we found that both the surface oxidation state and the activity of the catalyst under steady-state conditions depend sensitively on the composition of the reaction gas atmosphere, specifically on the CO:O2 ratio, and that there is a strict correlation between these quantities. A simple kinetic model is introduced, which allows to quantitatively determine the ratio of the effective reaction rate constants for reduction and oxidation of the TiO2 support surface. These results and ideas are considered to be of general relevance for the understanding of Mars-van Krevelen type reactions and specifically of oxidation reactions on supported Au catalysts, and they lend further support to previous proposals of a Au-assisted Mars-van Krevelen mechanism for this reaction.

Ag supported on CeO2 with different morphologies for the catalytic oxidation of HCHO

Ag/CeO2 catalysts with various shapes of CeO2 (nanorods, nanoparticles, and nanocubes) were prepared by the hydrothermal and impregnation method and then used for the catalytic oxidation of HCHO at low temperature. TEM and XRD results showed that Ag nanoparticles were well dispersed on the surface of CeO2. According to the results from XPS, H2-TPR and Raman spectra, Ag/r-CeO2, Ag/p-CeO2 and Ag/c-CeO2 exhibited different oxygen vacancy concentration, more oxygen vacancy and surface chemisorbed oxygen formed in Ag/r-CeO2. There might existed synergetic interaction between Ag and CeO2, and the presence of Ag nanoparticles could promoted the activation of surface chemisorbed oxygen, which is favorable for HCHO oxidation. The catalytic properties of the catalysts were significantly dependent on the shapes of CeO2, due to the highest surface oxygen vacancy concentration and best reducibility, Ag/r-CeO2 exhibited the best catalytic activity for HCHO oxidation. Ag/r-CeO2 showed higher specific reaction rate (7.43 nmol/(s·m2) at 100 °C) and TOFAg (0.0071 s−1 at 100 °C) under 810 ppm of HCHO and 84,000 h−1 of GHSV. Ag/r-CeO2 could reach complete HCHO oxidation at around 110 °C, which was lower than that of Ag/p-CeO2 and Ag/c-CeO2. Higher low-temperature reducibility, more surface oxygen vacancies, surface lattice oxygen species, and lattice defects produced by the interaction of Ag and CeO2 contributed to the excellent catalytic performance of Ag/r-CeO2 for HCHO oxidation. These results revealed that the HCHO catalytic oxidation activity was dependent on the shapes of CeO2 supports, this study suggested that the catalytic activity of the metal/CeO2 catalysts can be regulated by engineering the shapes of CeO2 supports.

Fe doped CeO2 nanosheets as Fenton-like heterogeneous catalysts for degradation of salicylic acid

Fe doped CeO2 nanosheets with various Fe/Ce ratios were synthesized by solvothermal method (ST) and catalytic performances were evaluated by the degradation of salicylic acid (SA) in the presence of H2O2 (Fenton-like oxidation). The Fe-CeO2 mixed oxides were characterized by SEM, TEM, XRD, EPR, Raman, H2-TPR and XPS, which indicated that 2% Fe doped CeO2 nanosheets (2Fe-CeO2) showed the largest concentration of surface oxygen vacancies and the highest catalytic activity under the optimum reaction conditions due to the complex adsorption of SA and H2O2 on the surface Ce3+. DMPO spin trapping EPR studies and analysis of intermediate products by LC-MS indicated that superoxide species (O2−/HOO) played a crucial role in the oxidation degradation process, meanwhile, the probable pathway of SA degradation was proposed. The strong adsorption of not-fully degraded low molecular weight organic acids (LMWOAs) on the active sites decreased the reusability of 2Fe-CeO2 catalyst, however, the catalytic activities could be recovered by a simple calcination treatment in air atmosphere.

Study of Ag/CeO2 catalysts for naphthalene oxidation: Balancing the oxygen availability and oxygen regeneration capacity

A series of Ag/CeO2 catalysts was synthesized by the incipient wetness method. Compared with Ag/Al2O3 and CeO2 catalysts, Ag/CeO2 catalysts are more promising candidates for naphthalene oxidation, in which Cex+ act as the main active sites and are efficiently promoted by Ag species. By characterizing the solid properties and the redox ability, the mechanism of ceria catalysis by the Ag-modified catalysts was investigated. It was found that Ag species can work as an oxygen pump to enhance the oxygen availability in the ceria bulk. They also promote the oxygen regeneration capacity by the oxygen spillover effect. However, such an effect would also decrease the ability for active oxygen regeneration at higher Ag loading, which arises from the lower surface oxygen vacancy concentration. Because of the balance between these two factors, the Ag/CeO2 catalyst with 1wt.% Ag shows the best performance for isothermal catalytic oxidation of naphthalene.

Oxygen vacancies promoted interfacial charge carrier transfer of CdS/ZnO heterostructure for photocatalytic hydrogen generation

The solid-state Z-scheme trinary/binary heterostructures show the advantage of utilizing the high-energy photogenerated charge carriers in photocatalysis. However, the key factors controlling such Z-scheme in the binary heterostructures are still unclear. In this paper, we showed that oxygen vacancies could act as an interface electron transfer mediator to promote the direct Z-scheme charge transfer process in binary semiconductor heterostructures of CdS/ZnS. Increasing the concentration of surface oxygen vacancies of ZnO crystal can greatly enhance photocatalytic hydrogen generation of CdS/ZnO heterostructure. This was attributed to the strengthened direct Z-scheme charge transfer process in CdS/ZnO, as evidenced by steady-state/time-resolved photoluminescence spectroscopy and selective photodeposition of metal particles on the heterostructure.

Boosting Cu-Ce interaction in CuxO/CeO2 nanocube catalysts for enhanced catalytic performance of preferential oxidation of CO in H2-rich gases

In this paper, a facile strategy by etching CeO2 spheres pretreated by different concentrations of H2SO4 or NaOH solution with an ionic liquid (IL) of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) under hydrothermal condition was developed to achieve CeO2 nanocubes. By depositing CuxO clusters on CeO2 nanocubes via a deposition−precipitation method, CuxO/CeO2 nanocube catalysts loading with different amounts of CuxO clusters were synthesized and the CuxO clusters were highly dispersed onto the surface of CeO2 nanocubes. The Raman spectroscopy, H2-TPR, XPS, and DRIFTS results reveal that there is a strong interaction between CuxO and CeO2. Among these CuxO/CeO2 catalysts, the 10CuCe-2OH-ILs, which was obtained via immersing CeO2 spheres using 2M NaOH, and subsequently being etched by ILs, and then loading ∼10% of copper, exhibits the optimal catalytic performances and stability. The catalytic activity of different catalysts increases in the order of 10CuCe-ILs <10CuCe-1H-ILs <10CuCe-0.1OH-ILs <10CuCe-5OH-ILs <10CuCe-2OH-ILs. The result is in agreement with the order of the surface oxygen vacancy concentration, reducibility and Cu+ content, suggesting that the interaction between CuxO species and surface oxygen vacancies of these CuxO/CeO2 catalysts plays an important role for CO preferential oxidation in H2-rich gases.