Dispersion Of CeO2 Research Articles

A study on the effect of nano-CeO2 dispersion on the characteristics of thermally-grown oxide (TGO) formed on NiCoCrAlY powders and coatings during isothermal oxidation

Abstract The present investigation is focusing on the high-temperature oxidation behavior of conventional and nano-CeO2 modified MCrAlY alloys, in the form of powders and coatings. Emphasis is placed upon the influence of MCrAlY alloy form on the oxidation performance. The NiCoCrAlY- CeO2 nanocomposite powders were prepared by mechanical milling and were subsequently thermally sprayed by high velocity oxygen-fuel (HVOF) technique. Isothermal oxidation tests were carried out at 1000 °C for up to 100 h. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) experimental analyses with thermodynamic equilibrium calculations were used for analysis of the oxide scales. The results indicated that the effect of nano-CeO2 addition on the oxidation properties was more pronounced in the form of coating. Moreover, the oxidation rate of the nano-CeO2 modified coating was found to be 87% lower than that of conventional coating, which was suggested to be related to the incorporation of nano-sized CeO2 dispersion into the Al2O3 scale. The different oxidation mechanisms were discussed.

Cerium Dioxide Particles to Tune Radiopacity of Dental Adhesives: Microstructural and Physico-Chemical Evaluation.

The insufficient radiopacity of dental adhesives applied under composite restorations makes the radiographic diagnosis of recurrent caries challenging. Consequently, the misdiagnosis may lead to unnecessary replacement of restorations. The aims of this study were to formulate experimental dental adhesives containing cerium dioxide (CeO2) and investigate the effects of different loadings of CeO2 on their radiopacity and degree of conversion for the first time. CeO2 was characterized by X-ray diffraction analysis, Fourier transforms infrared spectroscopy, and laser diffraction for particle size analysis. Experimental dental adhesives were formulated with CeO2 as the inorganic filler with loadings ranging from 0.36 to 5.76 vol.%. The unfilled adhesive was used as a control. The studied adhesives were evaluated for dispersion of CeO2 in the polymerized samples, degree of conversion, and radiopacity. CeO2 presented a monoclinic crystalline phase, peaks related to Ce-O bonding, and an average particle size of around 16 µm. CeO2 was dispersed in the adhesive, and the addition of these particles increased the adhesives’ radiopacity (p < 0.05). There was a significant decrease in the degree of conversion with CeO2 loadings higher than 1.44 vol.%. However, all materials showed a similar degree of conversion in comparison to commercially available adhesives. CeO2 particles were investigated for the first time as a promising compound to improve the radiopacity of the dental adhesives.

Enhanced activity and SO2 resistance of Co‐modified CeO2‐TiO2 catalyst prepared by facile co‐precipitation for elemental mercury removal in flue gas

The Co‐modified CeO2‐TiO2 catalyst prepared by facile co‐precipitation was used for efficient elemental mercury oxidation in flue gas. Results indicated that Co doping greatly enhanced the activity and SO2 resistance of the CeO2‐TiO2 catalyst. In the presence of 5% O2, 500 ppm NO, 800 ppm SO2 and 3% H2O at 200 °C, the Hg0 removal efficiency of CeCo3/Ti could maintain at about 87% for a relatively long time. Characterizations of catalysts (BET, XRD, Raman spectroscopy, TEM, H2‐TPR, O2‐TPD, XPS, TG‐MS and SO2‐DRIFTS) were carried out to reveal the mechanism of Co modification on the redox ability, SO2 resistance and resultant mercury oxidation removal performance of catalyst. It was found that an interaction of Ce with Co promoted the dispersion of CeO2, increased chemisorbed oxygen concentration, and improved the oxygen storage capacity and the reducibility of catalyst, which was beneficial to the improvement of Hg0 oxidation removal. Hg0 would adsorb onto the catalyst and react with surface active oxygen species replenished by gas‐phase O2 to be oxidized via Mars‐Maessen mechanism. SO2 consumed the surface active oxygen species and resulted in the reduction of Ce4+ to Ce3+, which induced the deactivation of catalyst. The introduced Co in CeO2‐TiO2 catalyst exerted the function of protecting Ce4+ from being poisoned by SO2 and thus promoted the sulfur resistance and Hg0 removal performance of the catalyst in the presence of SO2.

Preparation of a CeO2/γ-Al2O3 composite and its catalytic degradation performance

CeO2/γ-Al2O3 composite catalyst has been prepared using CeO2 as an active component and γ-Al2O3 as a support to remove dye from wastewater by catalytic degradation. The catalytic performance of the CeO2/γ-Al2O3 sample for the degradation of methylene blue is studied under visible light irradiation. The results show the presence of γ-Al2O3 and CeO2 with a cubic fluorite structure in the CeO2/γ-Al2O3 samples synthesized at 550°C. Small CeO2/γ-Al2O3 particle and a good dispersion of CeO2 are achieved with loading of CeO2. The loading of CeO2 on γ-Al2O3 also increases the total pore volume and pore diameter, which results in a high specific surface area of 132.03 m2/g, a total pore volume of 0.74 cm3/g, and a mean pore diameter of 22.54 nm. The photocatalytic degradation efficiency of methylene blue by the CeO2/γ-Al2O3 catalyst is higher than those of CeO2 and γ-Al2O3. Under the same conditions the CeO2/γ-Al2O3 catalyst achieves 98.36% degradation at 80 min, higher 5.0% and 11.9% degradation than CeO2 and γ-Al2O3, respectively. The high efficiency is attributed to promotion of the structural and textural performance of the CeO2/γ-Al2O3 catalyst by synergistic interaction between CeO2 and γ-Al2O3. These performances promote a larger surface area, higher content of acid sites, more •OH radicals and higher redox properties of the catalyst. The catalytic reaction kinetics could be fitted by the heterogeneous Langmuir-Hinshelwood model and the pseudo-first order rated constant for kapp is 17.5×10−2, which is 1.33 and 2.5 times as big as those of CeO2 and γ-Al2O3, respectively. CeO2/γ-Al2O3 catalyst suggests promising application for practical dye pollutant treatment.

Aqueous gelcasting of CeO2 ceramics using water-soluble epoxide

Manufacturing of CeO2 ceramics by an aqueous gelcasting shaping process was studied. This study has focused on the identification of critical parameters that influence the properties of suspensions and CeO2 ceramics. It is shown that ethylene glycol diglycidyl ether (EGDGE) and 3,3-diaminodipropylamine (DPTA) are suitable gelling agents for gelcasting process. This system has many advantages as low toxicity, limited impact on suspensions viscosity, and it does not disturb CeO2 dispersion by ammonium polyacrylate (PAA) in water. As a result, suspensions with high solid loading of 50 vol% were obtained. Solid loading appears as a critical parameter to control suspensions rheology, casting feasibility and final microstructural features of CeO2 ceramics. Finally, CeO2 ceramics with high relative density (>96%), good surface finish and complex shape were manufactured by gelcasting and natural sintering at 1500 °C for 1 h.

Microstructural Changes and Mechanical Response of Aluminum-Based Composites Prepared with Dispersed CeO2 Nanoparticles

The effect of CeO2 nanoparticles on the microstructure of two different metal matrixes, AA2024 aluminum alloy and pure aluminum, were studied. The aluminum-based composites were synthesized by mechanical milling and subsequently sintering at 550°C under an argon atmosphere. The microstructural evolution of consolidated composites was evaluated by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The experimental results revealed that the addition of CeO2 nanoparticles in the AA2024 alloy produced a dispersed needle-like Ce-Cu-rich phase that reduces the hardness of samples after sintering. On the contrary, the dispersion of CeO2 in pure aluminum shows significant improvement of hardness in comparison with the reinforced and unreinforced AA2024 aluminum alloy. During the sintering, the CeO2 nanoparticles show higher chemical stability in the aluminum matrix in comparison with the AA2024 matrix.

Enhanced Activity of Nb-modified CeO2/TiO2 Catalyst for the Selective Catalytic Reduction of NO with NH3

A series of CeO2-Nb2O5/TiO2 catalysts were prepared by an impregnation method and investigated for the selective catalytic reaction (SCR) of NO with NH3. The 15 wt.% CeO2–10 wt.% Nb2O5/TiO2 catalyst (CeNbTi) exhibited the highest activity and resistance to a high gas hourly space velocity and K2O. In the presence of H2O and SO2, it also showed better activity than the CeTi catalyst. The addition of Nb could improve the dispersion of CeO2 and increase the amount of Ce3+ and chemisorbed oxygen species on the catalyst surface, which enhances the catalytic activity of CeTi. The superior SCR activity of CeNbTi might also be attributed to its high redox ability, the enhanced adsorption capacity of NH3 species and the synergistic action between Ce, Nb and Ti species.

Effect of Mg/Al molar ratios on NO reduction activity of CO using Ce-La/MgAl2O4-x catalysts

A series of Ce-La/MgAl2O4-x catalysts were prepared by the incipient wetness impregnation method and characterized by BET, XRD, H2-TPR, CO-TPR and in situ FT-IR. The results demonstrate that the catalyst with a Mg/Al molar ratio of 0.5 yields the most uniform dispersion of CeO2 and greatly enhances formation of Ce-O-La solid solution, resulting in the increase of oxygen vacancy and surface Ce3+ content. Thereby, the synergistic effect between surface Ce3+ and oxygen vacancy gives rise to the best catalytic performance of NO reduction. Moreover, introduction of Mg species suppresses tranformation of CeO2 to Ce(SO4)2/Ce2(SO4)3 and then improves the SO2 resistance performance of Ce-La/MgAl2O4−0.5.

STUDY OF DISPERSE SYSTEMS OF CeO2 AND CeF3 IN STIFFENED MELTS NaNO3-KNO3 BY METHODS OF SPECTROSCOPY OF DIFFUSE REFLECTANCE AND BY THE CHEMICAL ANALYSIS

Processes of dispersion and solubility of CeO2 and CeF3 in the melts of systems NaNO3-KNO3 which are widely used as medium for synthesis of various oxide materials are investigated. The basis of the mechanism of the specified processes is made by the acid-basic and oxidationreduction reactions between initial substances and saline melt. For identification and definition of oxidation degree of Cerium in interaction products are applied spectroscopy of diffuse reflectance in an UV range of a spectrum and the substantial chemical analysis with use as a reagent of a solution of phosphoric acid. For reduction of influence of own absorption of ions NO3– as the sample of comparison it is used stiffened melt of NaNO3-KNO3. Definition of content of Ce(III) is carried out basing on decrease of intensity of coloring of KMnO4. Content of Ce(IV) is established photometrically on intensity of absorption of a phosphate complex (at high content of Ce(IV)) and on decrease of coloring of methanyl yellow (at low content). The data of spectroscopy of diffuse reflectance specifies in prevalence of Ce(IV) with small admixture of Ce(III) in case of system CeO2-(NaNO3-KNO3) and Ce(III) with admixture of Ce(IV) in case of system CeF3-(NaNO3-KNO3). Because of influence of H3PO4 on oxidation degree of cerium in last system, definition of Ce(III) and Ce(IV) by chemical analysis was not carried out. As for system with CeO2, contents of Ce(IV) by method of the chemical analysis are established at level 8-16%масс., and they are higher at system heat treatment on air in comparison with heat treatment in an inert (He) medium. Some inconsistency in the results received by a method of spectroscopy of diffuse reflectance and the chemical analysis, which reason while up to the end is not established, is observed. The role of the superficial phenomena on border solid state – saline melt - gas in processes of dispersion of CeO2 and CeF3 is shown.

Development of growth and thermal stresses in NiO scale on nanocrystalline Ni without and with dispersion of CeO2 nanoparticles

The development of growth and thermal stresses in the NiO scale on a nanocrystalline (NC) Ni without and with the dispersion of CeO2 nanoparticles during isothermal oxidation in air at 800°C and subsequent cooling has been analyzed by using a two-sided oxidation deflection testing. The CeO2 dispersion causes the NC Ni to form a NiO scale which accommodates higher growth stresses during oxidation but lower thermal stresses during cooling. The result is interpreted by characterization of the effect of CeO2 dispersion on the growth mechanism and microstructure of the NiO scale on the NC Ni.

Promoting oxidative activity and stability of CeO2 addition on the MnOx modified kaolin-based catalysts for catalytic combustion of benzene

In this paper, a new kaolin-based NaY-type zeolite crystal (KL-NY) material was synthesized through in-situ crystallization, and CeO2-modified KL-NY-supported manganese oxide catalysts (MnCeOx/KL-NY) were further prepared and investigated for benzene combustion. The texture-structure, surface morphology, dispersion of active components and the redox properties of the materials were systematically characterized and analyzed by the techniques of N2 adsorption-desorption, high resolution transmission electron microscopy (HRTEM)-energy dispersive spectroscopy (EDS) as well as the H2 temperature-programmed reduction (H2-TPR). The results showed that the calcinated and crystallized KL-NY support exhibited good thermal stability with large specific surface area and large pore volume. The MnCe/KL-NY catalysts exhibited excellent deep oxidation properties. Among them, 10%MnCe(9:1)/KL-NY displayed the highest catalytic activity and could completely oxidize low-concentration benzene at 260°C; its activity did not decrease after continuous reaction for 800 h, indicating its high potential for industrial application. The improved catalytic properties of the MnCe/KL-NY catalysts were mainly related to the higher oxidation state of MnOx and the preferable redox properties, resulted from the highly dispersion of CeO2 and MnOx on the surface of KL-NY as well as their strong interaction.

Enhanced Performance of Ceria-Based NOx Reduction Catalysts by Optimal Support Effect.

CeO2-based catalysts have attracted widespread attention in environmental-protection applications, including selective catalytic reduction (SCR) of NO by NH3, and their catalytic performance is often intimately associated with the supports used. However, the issue of how to choose the supports of such catalysts still remains unresolved. Herein, we systematically study the support effect in SCR over CeO2-based catalysts by using three representative supports, Al2O3, TiO2, and hexagonal WO3 (HWO), with different acidic and redox properties. HWO, with both acidic and reducible properties, achieves an optimal support effect; that is, CeO2/HWO exhibits higher catalytic activity than CeO2 supported on acidic Al2O3 or reducible TiO2. Transmission electron microscopy and X-ray diffraction techniques demonstrate that acidic supports (HWO and Al2O3) are favorable for the dispersion of CeO2 on their surfaces. X-ray photoelectron spectroscopy coupled with theoretical calculations reveals that reducible supports (HWO and TiO2) facilitate strong electronic CeO2-support interactions. Hence, the excellent catalytic performance of CeO2/HWO is mainly ascribed to the high dispersion of CeO2 and the optimal electronic CeO2-support interactions. This work shows that abundant Brønsted acid sites and excellent redox ability of supports are two critical requirements for the design of efficient CeO2-based catalysts.

Multicomponent NiSnCeO2/C catalysts for the low-temperature glycerol steam reforming

In this work, the low-temperature hydrogen production via glycerol steam reforming over activated carbon-supported Ni and Ni-Sn catalysts promoted by ceria was studied. A combination of N2 adsorption, powder X-ray diffraction, temperature-programmed reduction with H2, X-ray photoelectron spectroscopy and TEM analysis were used to characterise the Ni-Sn-CeO2 interactions and the CeO2 dispersion over the activated carbon support. The catalytic activity results show that the presence of ceria enhances the water-gas shift reaction, thus promoting the selectivity towards hydrogen. The inclusion of Sn stresses the influence of ceria in the displayed performance. Moreover, the formation of a Ni-Sn alloy seems to be an efficient way to mitigate Ni sintering and therefore to improve the overall catalyst’s stability.

The enhanced high cut-off voltage electrochemical performances of LiNi0.5Co0.2Mn0.3O2 by the CeO2 modification

The CeO2 nano-particles dispersed on the surface of commercial LiNi0.5Co0.2Mn0.3O2, have been prepared by a co-precipitation method, in which ammonium carbonate or ammonium oxalate is served as a precipitant to generate the different precursor of CeO2, respectively. CeO2-modified LiNi0.5Co0.2Mn0.3O2 composites with ammonium oxalate as the precipitant exhibit the best electrochemical properties with a reversible lithium storage capacity of 157.7mAhg−1 with a retention of 86.36% at 25°C at the current density 1C after 100 cycles under high cut-off voltage 4.6V. At higher temperature 55°C, its discharge capacity changes from 198.2mAhg−1 to 136.6mAhg−1 after 100 cycles, with a retention of 68.29%. Besides, it also displays an excellent rate performance with a capacity of 114.0mAhg−1 at 5C in the 100th cycle. All enhanced performances could be due to the dispersion of CeO2 on the surface of commercial LiNi0.5Co0.2Mn0.3O2 and the synergistic effects between the CeO2 and LiNi0.5Co0.2Mn0.3O2, which leads to the enhanced structural stability and electric conductivity.

The reactive element effect of ceria particle dispersion on alumina growth: A model based on microstructural observations.

The oxidation kinetics of alumina-forming metals can be affected by adding a small amount of a reactive (normally rare earth) element oxide (RExOy) and the segregation of the reactive element (RE) ions to the growing alumina grain boundaries (GBs) has been considered as a responsible reason. However, this interpretation remains a controversial issue as to how RE ions are produced by RExOy which is thermodynamically and chemically stable in metals. The question is answered by a model that is based on transmission electron microscopy (TEM) investigation of a CeO2-dispersed nickel aluminide oxidized in air at 1100 °C. The CeO2 dispersion is incorporated into the alumina scale by the inward growth of inner α-Al2O3, where it partially dissolves producing tetravalent Ce cations which then transform to trivalent cations by trapping electrons. The trivalent cations segregate to the α-Al2O3 GBs and diffuse outward along first the GBs and later the twin boundaries (TBs) in the outer γ-Al2O3 layer, being precipitated as Ce2O3 particles near surface.

Low-Temperature Selective Catalytic Reduction with NH&lt;sub&gt;3&lt;/sub&gt; over MnO&lt;sub&gt;x&lt;/sub&gt;-CeO&lt;sub&gt;2&lt;/sub&gt; Catalysts Supported on Nano Tetragonal Zirconia

The MnOx-CeO2/t-ZrO2 catalyst was prepared by impregnation with nano t-ZrO2 as the support. The influence of active component and reaction temperature on denitration performance of catalyst was investigated. The results showed that denitration efficiency improved as active component increased and reaction temperature rose. The denitration efficiency of 2.5% MnOx-CeO2/t-ZrO2 at 100°C was 68.1% while 15% MnOx-CeO2/t-ZrO2 was 97.4%. The results of XRD, BET and H2-TPR showed that surface structure of loaded catalyst was good for oxidation-reduction and denigration. NH3-TPD test demonstrated that NH3 was mainly adsorbed at Lewis acid sites on the surface of catalysts and became coordination NH3. Intermediate product NH2NO generated from reactions between coordination NH3 and NO which finally changed into N2 and H2O.NOx are potentially harmful to humans as a kind of primary pollutants. And NOx are the main cause of many environment problems, such as acid rain, surface ozone pollution and Particulate Matter 2.5[1]. The emission of NOx was 2337.8 tons in China in 2011 and that was 2275.4 tons[2]. The environmental situation is grim although the emission of NOx had begun decreasing. Emission standard of air pollutants for thermal power plants which came into effect on January 1, 2012 require the emission concentration of NOx under 100mg·m-3. The task is arduous.Selective catalytic reduction (SCR) of NOx with NH3 is the most promising method to remove NOx and catalysts with high activity play a decisive part in low temperature SCR technology. Many researches about metal oxide as SCR catalyst support have been reported recently, such as TiO2[3], Al2O3[4], activated carbon[5] and molecular sieve[6]. Zirconium oxide has attracted considerable attention recently as a catalyst support because of its special characteristics. Takahashi et al.[7] investigated the influence of the various compositions of TiO2 and ZrO2 on the NOx removal ability over a sulfur-treated NSR catalyst and came to a conclusion that ZrO2 support suppressed the solid phase reaction with potassium. Reddy et al.[8, 9] investigated structural characteristics of nanosized ceria-silica, ceria-titania, and ceria-zirconia mixed oxide catalysts and found these mixed oxides exhibit better redox properties than pure CeO2. YAN Zhi-yong et al.[10] reported that the existence of ZrO2 in catalysts can raise its specific area and enhance the dispersion of CeO2 on catalysts which results in high activity of the catalysts. CeO2/TiO2-ZrO2 catalyst has strong tolerance to water vapor and sulfur dioxide.It is well known that ZrO2 exists mainly in three polymorphs with monoclinic (m-ZrO2), tetragonal (t-ZrO2) and (c-ZrO2) cubic structures[11]. ZrO2 polymorphs have different amphoteric character of its surface hydroxyl groups. The crystalline phase of ZrO2 has a great effect on the structure, activity and selectivity of catalysts. Therefore, it is valuable to investigate the effects of nanocrystalline zirconia polymorphs on catalytic properties of MnOx-CeO2/t-ZrO2 Catalysts which few researchers have concerned about. In this study, we try to investigate catalytic activity and microstructure of SCR catalysts with manganese oxide and cerium oxide supported on t-ZrO2.

Influence of preparation methods of La2CoMnO6/CeO2 on the methane catalytic combustion

Novel supported rare earth double perovskite oxide La2CoMnO6/CeO2 was synthesized by three methods (precipitation, sol–gel and impregnation) calcined at 900°C and investigated in the catalytic combustion of methane. The catalysts were characterized by XRD, BET, SEM, TEM, H2-TPR and XPS techniques. The results showed that methane catalytic combustion activity was markedly influenced by the preparation method, and their catalytic activities were varied in the order of precipitation>sol–gel>impregnation. La2CoMnO6/CeO2 (precipitation) has the best activity (T90 is 613°C), and lowest activation energy (only 59.8kJ/mol). The preparation method of precipitation can not only lead to strengthening the interaction between the La2CoMnO6 and CeO2, but also significantly promote high dispersion of CeO2 to accelerate the circulation of the oxygen species. We also investigated the mechanism of supported rare earth double perovskite oxide La2CoMnO6/CeO2 in CH4 combustion. Higher ratio of Mn4+/Mn4+and Co3+/Co3+ as well as the presence of abundant lattice oxygen would play an important role in promoting methane catalytic combustion.

Spectroscopic characterization and catalytic activity of Rh supported on CeO2-modified Al2O3 for low-temperature steam reforming of propane

The present work aims at clarifying the effects of CeO2 addition to Al2O3 support on the surface chemical characteristics and catalytic activity of supported Rh catalysts for low-temperature steam reforming of propane. Steam reforming of propane was carried out at 500°C over Rh catalysts supported on alumina modified with different CeO2 loading (0, 5, 10, 20, 50, 75, and 100wt%). The Rh catalyst supported on 20wt% CeO2-modified alumina (2Rh/20CeAl) showed the highest propane and steam conversions, followed in decreasing order by those with 10, 5, 50, 75, 0, and 100wt% CeO2. TPR results show that the interaction between ceria and rhodium improves the reducibility of both rhodium oxide and ceria. XPS analysis indicates strong ceria–alumina interaction and strong Rh-support interaction for Rh catalysts with CeO2 loading less than 20wt%. Field-Emission SEM and AES results revealed that at 20wt% CeO2 loading, ceria was dispersed as separate nano-particles with sizes of 100–200nm on the alumina surface. At high CeO2 loading (≥50wt%) ceria particles formed conglomerates covering alumina surface. The 2Rh/20CeAl catalyst showed the highest activity for propane steam reforming possibly because the high CeO2 dispersion created a large area of ceria–alumina interface which helped increase Rh dispersion, and the strong interaction between Rh and support helped enhance the reducibility of ceria and rhodium oxide. Rh loaded onto the interfacial region of ceria and alumina is considered to be most active for the 2Rh/20CeAl catalyst.

Multishell hollow CeO2/CuO microbox catalysts for preferential CO oxidation in H2-rich stream

Multishell hollow CuO microbox was synthesized by a template method and the Ce(IV) nitrate solution was impregnated into the hollow cavity of the CuO support. The as-prepared catalysts were characterized by FESEM, TEM, XRD, N2 physisorption and H2-TPR. It is found that the alternate CuO and CeO2 multishell structure reduces the agglomeration of CuO species and improves the dispersion of CeO2. The special structure ensures even distribution of the two species in the material matrix and the optimum ratio of CeO2 to CuO provides two-component active sites with high concentration. Thus, the wider full CO conversion window and higher CO2 selectivity are achieved over the 30CeO2/CuO microbox catalyst.

CeO2-promoted Ni/activated carbon catalysts for the water–gas shift (WGS) reaction

The low temperature water–gas shift (WGS) reaction has been studied over carbon-supported nickel catalysts promoted by ceria. To this end, cerium oxide has been dispersed (at different loadings: 10, 20, 30 and 40 wt.%) on the activated carbon surface with the aim of obtaining small ceria particles and a highly available surface area. Furthermore, carbon- and ceria-supported nickel catalysts have also been studied as references. A combination of N2 adsorption analysis, powder X-ray diffraction, temperature-programmed reduction with H2, X-ray photoelectron spectroscopy and TEM analysis were used to characterize the Ni–CeO2 interactions and the CeO2 dispersion over the activated carbon support. Catalysts were tested in the low temperature WGS reaction with two different feed gas mixtures: the idealized one (with only CO and H2O) and a slightly harder one (with CO, CO2, H2, and H2O). The obtained results show that there is a clear effect of the ceria loading on the catalytic activity. In both cases, catalysts with 20 and 10 wt.% CeO2 were the most active materials at low temperature. On the other hand, Ni/C shows a lower activity, this assessing the determinant role of ceria in this reaction. Methane, a product of side reactions, was observed in very low amounts, when CO2 and H2 were included in the WGS feed. Nevertheless, our data indicate that the methanation process is mainly due to CO2, and no CO consumption via methanation takes place at the relevant WGS temperatures. Finally, a stability test was carried out, obtaining CO conversions greater than 40% after 150 h of reaction.