Ceria Samples Research Articles

Characterization and optical properties of Eu-doped cubic nano ceria synthesized by using the co-precipitation-hydrothermal route

A series of nano ceria samples containing 0 to 2 mol% europium were synthesized following the co-precipitation hydrothermal technique. The X-ray diffraction patterns showed peaks corresponding to the fluorite structure of cubic ceria with shifting of the peak positions, but did not show any Eu-related peaks. The fourier transform infrared (FTIR) spectra of all the samples showed four bands that could be attributed to Ce-O stretching vibrations, formation of nano-crystalline particles, -HOH bending, and -OOH and -OH stretching vibrations. The Raman spectra of all the samples showed a sharp and intense Raman shift at around 460–462 cm−1 corresponding to the triplydegenerate F2g mode. The intensity of the Raman peaks showed variations in intensities. The transmission electron microscope (TEM) images of typical samples revealed that the shapes and the sizes of the particles were not much affected after Eu doping in the studied range though Eu doping resulted in agglomerations of nanoparticles. Broad absorption peaks centered at 292, 332, 336, 310, and 294 nm were observed for 0, 0.25, 0.5, 1, and 2 mol % Eu-doped ceria in the UVVis spectra with direct band gaps of 3.6, 2.75, 2.75, 2.75, and 3.25 eV, respectively. The smaller values of the indirect band gap indicated that Eu-doped nanoparticles were available to assist the indirect electron transition from the valence band to the conduction band. The emission peaks for the spectra obtained by exciting at 300 nm were observed at 355, 405, 396, 387, and 380 nm for pure ceria sample and 0.25, 0.5, 1, and 2 mol% Eu-doped samples, confirming the red shift in all the doped samples. The spectra for Eu-doped samples obtained by exciting at 500 nm showed three peaks in the orange-red region corresponding to the 5D0 → 7Fj (j = 0 − 4) transitions of Eu3+.

Controlled synthesis of ceria nanoparticles for the design of nanohybrids

Ceria nanoparticles were synthesized from reaction mixture of cerium nitrate/hexamethylenediamine/water–ethylene glycol. Lamellar, particle-aggregated array, platelet, rice, cube, quasi-sphere shapes of the ceria nanoparticles can be controlled by tuning reaction parameters (reagent concentration, reagent components, pH, and reaction conditions). Studies on shape-dependent catalysis of the bare ceria samples toward CO oxidation indicated that the cube-shaped ceria nanoparticles show better catalytic activity than the nanospheres and the commercial micropowders. As capped by hexamethylenediamine (HEA) molecules, amine-functionalized ceria nanoparticles act as platforms for depositing copper particles to produce efficient Cu/CeO2 hybrid nanocatalysts for CO conversion. Coupling of the copper clusters with the HEA-capped ceria nanocubes was achieved with the Cu contents up to 15wt.%. The Cu/CeO2 nanohybrids show an enhanced catalytic efficiency of low temperature CO conversion. This could be due to high exposure of the reactive {100} facets in the ceria nanocubes and interfacial copper–ceria interactions.

Gold supported on ceria nanoparticles and nanotubes

The ceria nanotubes with different size have been prepared via a hydrothermal treatment of CeO2 nanoparticles at 120°C with two different NaOH concentrations (5 or 10M) for 36h. The synthesized ceria samples characterized by SEM, TEM, XRD, and UV–visible spectroscopy were used as supports for Au/CeO2 catalysts preparation by DP technique using HAuCl4 as gold precursor and urea as precipitation agent. The formation of gold nanoparticles (Au NPs) has been studied by TEM, in situ UV–visible–mass analysis at temperature programmed reduction and XPS spectroscopy. Three distinguishable steps in the formation of Au NPs accompanied by profound ceria reduction particular for ceria nanotubes have been found. Au NPs stabilized on the ceria nanotubes have been characterized with higher activity in CO oxidation than those supported on ceria nanoparticles. The structure and redox treatment of ceria nanotubes affects size of Au NPs and their catalytic activity in CO oxidation. Pre-oxidized Au/CeO2-nanotubes manifest the highest activity in CO oxidation.

Higher activity of Diesel soot oxidation over polycrystalline ceria and ceria–zirconia solid solutions from more reactive surface planes

High temperature treatment under air of samples of polycrystalline ceria and ceria–zirconia is shown to induce a rearrangement of crystals, with a surface structural evolution of the oxides toward the formation of more reactive exposed planes belonging to the {100} and {110} families, associated with a decrease of the exposure of the less reactive {111} facets. This is dependent on the amount of ceria, being more evident with pure CeO2, and less important with increasing ZrO2 content. A correlation between the exposure of more reactive planes and the specific rate of carbon soot oxidation is found, in agreement with previous results obtained in monodimensional nanoshaped and polycrystalline ceria samples for CO oxidation. This suggests that Diesel soot oxidation catalysts might be designed by keeping into consideration also these effects.

Preparation and characterization of Ce1−x(Gd0.5Pr0.5)xO2 electrolyte for IT-SOFCs

The Ce1−x(Gd0.5Pr0.5)xO2 (x = 0–0.24) compositions were synthesized through the sol–gel process followed by low temperature combustion. X-ray diffraction data analysis showed that all the samples exhibit a cubic structure with single phase. The lattice parameter was calculated by rietveld refinement of XRD patterns. Dense ceramics were prepared by sintering the pellets at 1300 °C. The relative density of the samples was over 98%. The surface morphology was studied by Scanning electron microscopy (SEM). Chemical composition was analyzed by Energy dispersive spectroscopy (EDX). A.C. impedance spectroscopy measurements were carried out to study the grain, grain boundary and total ionic conductivity of co-doped ceria samples in the temperature range 150–700 °C. The Ce0.84(Gd0.5Pr0.5)0.16O2 composition showed highest grain ionic conductivity i.e., 1.059 × 10−2 S/cm at 500 °C which is 11.5% higher than the Ce0.9Gd0.1O2 (with an activation energy 0.62 eV). At intermediate temperatures, the Ce1−x(Gd0.5Pr0.5)xO2 materials were found to be ionic in nature.

Rare Earth doped ceria: a combined X-ray and neutron pair distribution function study

Rare Earth doped ceria materials (Ce1–xRExO2–x/2) are widely studied for their application in solid oxide fuel cell devices. In this work, RE(Yb, Y, Nd, La)-doped ceria samples at constant (x = 0.25) doping rate were subjected to a combined synchrotron radiation and neutron powder diffraction study. The dopants were chosen in order to cover a wide range of dopant-ionic radii. The effect of doping on the average structure is investigated using conventional Rietveld analysis, while the Pair Distribution Function technique is used to explore the spatial extent of disorder as well as the local structure. Two models for mapping the local structure, in terms of oxygen relaxation and nano-phase separation, are presented.

Effective Heat and Mass Transport Properties of Anisotropic Porous Ceria for Solar Thermochemical Fuel Generation.

High-resolution X-ray computed tomography is employed to obtain the exact 3D geometrical configuration of porous anisotropic ceria applied in solar-driven thermochemical cycles for splitting HO and CO. The tomography data are, in turn, used in direct pore-level numerical simulations for determining the morphological and effective heat/mass transport properties of porous ceria, namely: porosity, specific surface area, pore size distribution, extinction coefficient, thermal conductivity, convective heat transfer coefficient, permeability, Dupuit-Forchheimer coefficient, and tortuosity and residence time distributions. Tailored foam designs for enhanced transport properties are examined by means of adjusting morphologies of artificial ceria samples composed of bimodal distributed overlapping transparent spheres in an opaque medium.

Morphology and nanostructure of CeO2(111) surfaces of single crystals and Si(111) supported ceria films

The surface morphology of CeO(2)(111) single crystals and silicon supported ceria films is investigated by non-contact atomic force microscopy (NC-AFM) and Kelvin probe force microscopy (KPFM) for various annealing conditions. Annealing bulk samples at 1100K results in small terraces with rounded ledges and steps with predominantly one O-Ce-O triple layer height while annealing at 1200K produces well-ordered straight step edges in a hexagonal motif and step bunching. The morphology and topographic details of films are similar, however, films are destroyed upon heating them above 1100K. KPFM images exhibit uniform terraces on a single crystal surface when the crystal is slowly cooled down, whereas rapid cooling results in a significant inhomogeneity of the surface potential. For films exhibiting large terraces, significant inhomogeneity in the KPFM signal is found even for best possible preparation conditions. Applying X-ray photoelectron spectroscopy (XPS), we find a significant contamination of the bulk ceria sample with fluorine while a possible fluorine contamination of the ceria film is below the XPS detection threshold. Time-of-flight secondary ion mass spectroscopy (TOF-SIMS) reveals an accumulation of fluorine within the first 5nm below the surface of the bulk sample and a small concentration throughout the crystal.

Ferromagnetism in rare earth doped cerium oxide bulk samples

AbstractMagnetic properties of rare earth (RE) doped ceria (RE = Nd, Sm, Gd, Tb, Er and Dy) samples have been investigated and reported in this paper. Room temperature ferromagnetism (FM) was observed in calcined powders as well as in sintered samples of Nd and Sm doped CeO2, whereas other RE dopants (Gd, Tb, Er and Dy) in CeO2 exhibit paramagnetic behaviour. The origin of magnetism in these samples can be related to oxygen vacancies and formation of fluorite crystal structure. Though the magnetization was found to be lower as compared to transition metal (TM) doped ceria, the segregation of metallic and secondary phases can be avoided in RE doped CeO2. CeO2 doped with Sm ions in different concentration (1, 5 and 15%) were also studied to see the dopant effects on magnetic properties. The origin of magnetism in these samples may be related to the oxygen vacancies created due to RE dopants, which was confirmed from the peak around 555 cm−1 in Raman spectra.

Structural Characterization and Redox Catalytic Properties of Cerium(IV) Pyrochlore Oxides

Ce(IV) pyrochlore oxides have been prepared by hydrothermal synthesis, and the parent material, a sodium cerium titanate, has been studied using total neutron scattering. While analysis of Bragg diffraction is consistent with an average cubic pyroclore structure, the profile is broadened because of the crystal size of <10 nm. Analysis of the pair distribution function (PDF) produced by Fourier transformation of the total scattering yields a structural model consistent with formulation of the parent material as (Na0.33Ce0.53Ti0.14)2Ti2O7. This contains a proportion of A-site titanium, consistent with the measured bulk density of the material. The PDF also contains evidence that the short-range order of the pyrochlore structure is disordered, with oxide anions displaced from the positions of the ideal Fd3m pyrochlore structure to give local symmetry F43m. These observations are supported by static (broadline) solid state 49Ti NMR measurements on a 49Ti isotopically enriched sample, which showed a dominant, narrow resonance at an apparent shift of δ – 912 ppm and a second minor resonance consistent with A-site titanium. Sn(IV) doping of the pyrochlore phase is possible by one-step hydrothermal synthesis: this gives a series of materials with a maximum tin content of Sn:Ti = 0.4:0.6, for which 119Sn solid-state NMR confirms the presence of octahedral, B-site Sn(IV), and powder X-ray diffraction shows an associated expansion of the pyrochlore lattice. Temperature programmed reduction/oxidation studies of the materials reveal that after an activation cycle the parent pyrochlore shows a reversible low temperature reduction at <200 °C, more facile than ceria itself. The Sn-doped analogues also show a low temperature reduction, but on continued heating collapse irreversibly to yield a mixture of products that includes SnO. The parent pyrochlore has been tested as a support for gold in the water gas shift reaction and shows a lower temperature conversion of H2O and CO to H2 and CO2 than a ceria sample of similar surface area.

Influence of the calcination temperature on the structure and reducibility of nanoceria obtained from crystalline Ce(OH)CO 3 precursor

A high yield green method was developed for the preparation of reactive nanotextured ceria (CeO 2). The preparation method is based on the oxidation of a crystalline Ce(OH)CO 3 precursor that decompose at relative low temperature (ca. 250 °C) yielding CeO 2 nanocrystals initially rich in Ce 3+. After increasing calcination temperatures (in the range 350–650 °C), PXRD analysis show a slight crystal growth after calcination temperatures up to 550 °C, however cell contraction in such case denotes the definitive oxidation of remnant Ce 3+ centers. XPS results confirm Ce 3+ fraction diminution as calcination temperature increases. TPR profiles of ceria samples show two reduction events being the low temperature one (at ca. 500 °C) related to a surface process in which approximately only one cerium monolayer is involved. Catalytic activity tests for COPROX reaction were performed under differential reactor conditions to evaluate their activity in the temperature range 100–300 °C. The optimum activity recorded for the sample calcined at 450 °C accounts for the compromise between oxide’s activation and surface preservation.

Electrical and thermal characterization of Sm 3+ doped ceria electrolytes synthesized by combustion technique

Nanocrystalline samarium doped ceria electrolyte [Ce 0.9Sm 0.1O 1.95] was synthesized by citrate gel combustion technique involving mixtures of cerium nitrate oxidizer ( O) and citric acid fuel ( F) taken in the ratio of O/ F = 1. The as-combusted precursors were calcined at 700 °C/2 h to obtain fully crystalline ceria nano particles. It was further made into cylindrical pellets by compaction and sintered at 1200 °C with different soaking periods of 2, 4 and 6 h. The sintered ceria was characterized for the microstructures, electrical conductivity, thermal conductivity and thermal diffusivity properties. In addition, the combustion derived ceria powder was also analysed for the crystallinity, BET surface area, particle size and powder morphology. Sintered ceria samples attained nearly 98% of the theoretical density at 1200 °C/6 h. The sintered microstructures exhibit dense ceria grains of size less than 500 nm. The electrical conductivity measurements showed the conductivity value of the order of 10 −2 S cm −1 at 600 °C with activation energy of 0.84 eV between the temperatures 100 and 650 °C for ceria samples sintered at 1200 °C for 6 h. The room temperature thermal diffusivity and thermal conductivity values were determined as 0.5 × 10 −6 m 2 s −1 and 1.2 W m −1 K −1, respectively.

Ceria associated manganese oxide nanoparticles: Synthesis, characterization and arsenic(V) sorption behavior

Four samples of ceria incorporated manganese oxide (NCMO) were prepared by co-precipitation-calcinations and sol–gel methods, and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, BET surface area etc. The synthetic samples were nanoparticle agglomerates with irregular surface morphology (Ce:Mn = 1:1). The NCMO-1b sample, prepared by the calcination of metal hydroxide at 573 K for 3.0 h, was a nano-crystalline (70–90 nm) and hydrated material having high BET surface area (116.96 m 2 g −1). The arsenic(V)-sorption by the samples at pH 7.0 (±0.2) and 30 °C showed that the NCMO-1b is a most efficient material. Optimum pH range for the arsenic(V) sorption is 3.0–7.0 at 303 (±1.0) K. Kinetics and equilibrium data obtained (pH = 7.0 ± 0.2, T = 303 ± 1.0 K and I = 0.01 M) had described the pseudo-second order kinetics and the Freundlich isotherm models well, respectively. Thermodynamics of the sorption reaction showed that the changes of enthalpy (Δ H°), entropy (Δ S°) and Gibbs free energy (Δ G°), respectively, were +23.901 kJ mol −1, +0.175 kJ mol −1 K −1 and −25.737 to −32.753 kJ mol −1 at T = 283–323 K. Estimation of the sorption energy ( E = 17.15 kJ mol −1) indicated that the arsenic(V) was chemisorbed on NCMO-1b. The phosphate only reduced the arsenic(V) removal efficiency of NCMO-1b.

Dual-Templating Preparation and Enhanced Low-Temperature Reducibility of Three-Dimensionally Ordered Macroporous Ceria with Mesoporous Walls

Three-dimensionally ordered macroporous (3DOM) ceria with mesoporous walls and cubic crystal structures were prepared with polymethyl methacrylate (PMMA) as a hard template and triblock copolymer Pluronic F127 (EO 106 PO 70 EO 106 ), cetyltrimethylammonium bromide (CTAB), or poly(ethylene glycol) (PEG) as a soft template. Citric acid was used as a complexing agent and cerium nitrate was used as a metal precursor. The 3DOM CeO 2 samples were characterized by numerous analytical techniques. The as-fabricated CeO 2 samples had a 3DOM architecture with polycrystalline wormhole-like mesoporous walls. The nature of the soft template had an important effect on the pore structure and the surface area of the final product. The surface areas of the F127-, CTAB-, and PEG-derived 3DOM CeO 2 samples (denoted CeO 2 -F127, CeO 2 -CTAB, and CeO 2 -PEG, respectively) were ca. 60.5, 60.2, and 51.8 m 2 /g, respectively. The low-temperature reducibility of the 3DOM-structured CeO 2 samples was much better than that of the bulk counterpart and the low-temperature reducibility of the three 3DOM ceria samples increased according to: CeO 2 -PEG < CeO 2 -CTAB < CeO 2 -F127, which coincided with the surface oxygen vacancy density sequence. The improved physicochemical properties associated with the formation of the 3DOM skeleton with wormhole-like mesoporous walls may be useful for applications such as CeO 2 materials in heterogeneous catalysis. 摘要：以聚甲基丙烯酸甲酯 (PMMA) 为硬模板, 三嵌段共聚物 F127、十六烷基三甲基溴化铵 (CTAB) 或聚乙二醇 (PEG) 为软模板剂 (表面活性剂), 柠檬酸为络合剂, 硝酸铈为金属前驱体, 采用双模板法成功地合成出具有介孔孔壁的三维有序大孔 (3DOM) 结构的立方相 CeO 2 样品 CeO 2 -F127, CeO 2 -CTAB 和 CeO 2 -PEG, 并利用多种分析技术表征了它们的物化性质. 结果表明, 三个样品均具有 3DOM 结构和蠕虫状介孔孔壁, 表面活性剂的种类对样品的孔结构和比表面积影响较大. 在制备过程中引入表面活性剂可提高 CeO 2 样品的比表面积, 所得 CeO 2 -F127, CeO 2 -CTAB 和 CeO 2 -PEG 样品的比表面积分别为 60.5, 60.2 和 51.8 m 2 /g. 具有 3DOM 结构的 CeO 2 样品的低温还原性显著好于无孔的体相 CeO 2 , 它们的低温还原性按照 CeO 2 -PEG < CeO 2 -CTAB < CeO 2 -F127 的顺序提高, 与其表面氧空位密度大小的顺序相吻合. CeO 2 因具有蠕虫状介孔孔壁的 3DOM 结构, 改善了其物化性质, 使此类材料在催化方面有着更广泛的应用前景. High-surface-area three-dimensionally ordered macroporous ceria with mesoporous walls and excellent low-temperature reducibility were prepared with polymethyl methacrylate as a hard template and triblock copolymer Pluronic F127, cetyltrimethylammonium bromide or poly(ethylene glycol) as a soft template while cerium nitrate was used as the metal source.

Mechanochemical Synthesis and Characterization of Calcium-doped Ceria Oxide Ion Conductor

Crystalline fluorite-like structure of Ca-doped CeO2 compounds was prepared via mechanochemical synthesis route. An in-depth study was conducted to optimize the processing parameters whereby three different variables associated with the milling process were studied; milling time, revolution per minute (rpm) and solvent medium. This work was conducted in pursuit of developing optimum milling process parameters for Ca-doped CeO2 oxide ion conductors. For the purpose of comparison, calcium-doped ceria samples were also prepared by conventional solid state method using CeO2 and CaCO3. The single phase compounds were characterized by employing differential thermal analysis/thermogravimetry (DTA/TG), X-ray diffractometry (XRD), infrared spectroscopy (IR), inductively coupled – plasma atomic emission spectroscopy (ICP-AES) and scanning electron microscopy (SEM). The electrical conductivity of sintered samples of calcium doped ceria compounds were investigated in air as a function of temperature using AC impedance spectroscopy.

Study of nano-structured ceria for catalytic CO oxidation

Mesoporous, nano-structured ceria has been synthesized using a low-cost biopolymer chitosan as a template, and the same material has been studied for its CO oxidation activity. The ceria thus prepared shows low crystallite size (6.5 nm), high surface area (BET-SA 144.2 m2 g−1) and mesopores (32.4 A) without ordered structure. Different ceria samples have been synthesized by manipulating the chitosan : cerium ratio and synthesis temperature. These ceria samples have been characterized using XRD, BET-SA, SEM, FTIR, UV-DRS, PL and TEM techniques. The ceria samples show fluorite structure with cubic symmetry and increased lattice volume. The nano-structured ceria thus synthesized lowers the CO oxidation temperature by 30–60 °C as compared to the commercial ceria. The improved catalytic activity primarily appears to be the effect of improved surface area and pore characteristics of nano-structured ceria. Also the expansion in lattice cell volume leads to the improvement in redox properties of ceria, thereby facilitating the formation of surface oxygen vacancies. Such mesoporous ceria without ordered structure could be useful as an oxidation catalyst as well as a support for various catalysts. The platinum incorporated mesoporous ceria also shows excellent CO oxidation.

Compositional tunability and high temperature stability of ceria–zirconia hollow spheres

Cerium oxide is a widely used catalyst support due to favorable oxygen storage and release properties. The present investigation was undertaken to improve the thermal stability of hollow ceria shells by incorporation of zirconium. Hollow ceria spheres were doped with zirconium in the range of 1–13 atomic percent by a solvothermal method. In situhigh-temperature XRD revealed that samples with greater than 5% zirconium were significantly more resistant to crystallite growth than pure ceria samples. Additionally, nitrogen adsorption porosimetry showed that doped samples retained their specific surface area to higher temperatures than undoped samples. Transmission electron microscopy was used to confirm high temperature stability (up to 1100 °C) of the hollow sphere morphology.

Exotemplated ceria catalysts with gold for CO oxidation

Cerium oxides were synthesized by an exotemplating procedure using both activated carbon and carbon xerogel as templates. The template effect and the preparation method were investigated. The surface area of the materials varied from 73 to 114 m 2 g −1, being similar to samples prepared by standard precipitation and calcination techniques (150 and 98 m 2 g −1, respectively), but much larger than a commercial ceria sample (20 m 2 g −1), used for comparison purposes. Samples prepared using xerogel as template have, approximately, twice as much porosity than those prepared with activated carbon, and the mesopores of the first are roughly 4 times larger than those of the latter. Cerianite CeO 2 was the only phase detected by XRD for all materials. Gold was loaded onto these materials by a double impregnation method. The catalytic performance of these ceria oxide materials alone and loaded with gold was tested in the oxidation of carbon monoxide. Xerogel prepared samples showed to be the most active in CO oxidation. Addition of Au increased the activity up to two orders of magnitude, at room temperature. With the unloaded samples, complete conversion was only achieved above 400 °C, but when Au was loaded, full CO conversion occurred already at 75 °C. Analysis of selected samples by HAADF and HRTEM showed that the gold particle size was 5–10 nm for the most active sample, and 8–13 nm for the least active. H 2-TPR experiments proved that addition of gold significantly helped to improve the reducibility of the surface oxygen on CeO 2. Both for ceria and Au/ceria materials, it was observed that the temperature at which the CO conversion started is related to the temperature of the first peak of the TPR spectrum, showing that the activity depends on the availability of surface oxygen. Experiments without oxygen in the feed, in the presence of ceria catalysts, suggest that the lattice oxygen can react with CO. It is shown that there is a significant correlation between the catalytic activity and the lattice oxygen donating ability. The TPR results suggest that gold is in its reduced state in the “fresh” Au/ceria samples.

Anode Side Diffusion Barrier Coating for Solid Oxide Fuel Cells Interconnects

During the operation of solid oxide fuel cells (SOFCs) the Ni base anode and/or Ni-mesh is in direct contact with the ferritic steel interconnect or the metallic substrate. For assuring long-term stack operation a diffusion barrier layer with high electronic conductivity may be needed to impede interdiffusion between the various components. A pre-oxidation layer on the ferritic steel turned out to be not viable as a barrier layer since a Ni-layer tends to dissociate the oxide scale. Therefore the potential of ceria as a diffusion barrier layer for the anode side of the SOFC was estimated. The barrier properties of a ceria coating between the Ni and the ferritic steel Crofer 22 APU were tested for 1000 h in Ar–4H2–2H2O at 800°C. Conductivity experiments were performed in the same atmosphere at different temperatures. After long-term exposures no indication of interdiffusion between Ni and ferritic steel could be detected, however, sputtered coatings on ferritic steel substrates showed significantly lower conductivities than bulk ceria samples because of void formation between the ceria and the oxide on the steel surface. The latter could be prevented by an intermediate copper layer, which resulted in overall area specific resistance values lower than 20 mΩ cm2 after 100 h exposure at 800°C.

H2 assisted decomposition of cerium nitrate to ceria with enhanced catalytic properties

Abstract CeO 2 samples were prepared by Ce(NO 3 ) 3 ·6H 2 O decomposition under synthetic air or 5%H 2 /N 2 at 500 °C. The samples were characterized by XRD, N 2 adsorption at − 196 °C, Temperature Programmed Reduction with H 2 (H 2 –TPR) and DRIFTS. The catalytic activity for CO oxidation was also tested. The main conclusion is that H 2 accelerates the decomposition of cerium nitrate to CeO 2 with regard to air decomposition, allowing preparation of ceria with enhanced catalytic behavior. The gas atmosphere used in the decomposition of the nitrates has no effect in the crystal size and surface area of the ceria samples obtained.