Formation Of Ce Research Articles

Cr-Doped CeO2 Nanorods for CO Oxidation: Insights into Promotional Effect of Cr on Structure and Catalytic Performance

Development of non-noble metal catalysts for oxidation of CO is an important subject for reducing the automotive emissions. Recently, shape-controlled synthesis of CeO2 has increasingly attracted the attention of researchers due to its size- and morphology-dependent unique properties. Following this line of thinking, herein, we successfully report the synthesis of Cr-doped CeO2 (Ce1−xCrxO2−δ; X = 0.05, 0.1, and 0.15) nanorods with various Cr contents by a facile hydrothermal method. Structural, surface, optical, and redox properties of the Cr-doped CeO2 nanorods were investigated by various techniques, namely, ICP-OES, TEM-HRTEM, FE-SEM/EDX/EDS, XRD, BET, Raman, UV–vis DRS, PL, XPS, H2-TPR, and O2-TPD. The catalytic performance was evaluated for CO oxidation. For comparison, the efficiency of Cr2O3 was also studied for CO oxidation under identical conditions. As revealed by various characterization results, the chromium ions were doped into the ceria lattice (formation of Ce–O–Cr solid solution), which enhanced the intrinsic properties such as oxygen vacancy concentration and surface area. It was found that the Cr-doped CeO2 nanorods show superior CO oxidation activity than the pristine counterparts (CeO2 nanorods and Cr2O3). The highest CO oxidation efficiency was achieved with the light-off temperature of T50 = 261 °C, when the Cr doping amount was 10% (Ce0.9Cr0.1O2−δ). A high specific surface area, more number of surface oxygen vacancies, a high concentration of Ce3+, and enhanced oxygen reducibility of Ce0.9Cr0.1O2−δ nanorods were found to be responsible for its superior catalytic performance. Further, the Ce0.9Cr0.1O2−δ nanorods exhibited a steady CO conversion over a period of 55 h investigated. The obtained results are expected to have a significant impact on the use of non-noble metal based Cr-doped CeO2 nanorods in environmental applications. The Cr-doped CeO2 nanorods with Ce0.9Cr0.1O2−δ composition showed enhanced CO oxidation performance at a lower temperature (~ 261 °C) than that of pristine CeO2 nanorods (338 °C) and Cr2O3 (361 °C) catalyst. This behaviour is a result of enhancement of oxygen vacancies, surface Ce3+ species, low-temperature reducibility, and high surface area.

Insight into optical properties of carbazole-supported on CeO2/TiO2 composite

In the paper, a series of CeO2/TiO2 composites doped with carbazole were synthesized by impregnation method. The characterizations of XRD, TG-DTG, FT-IR, UV–vis adsorption, FESEM and FL spectra were adopted to analyze the structures and optical properties of these obtained samples. XRD, TG-DTG and FESEM results showed that these samples were successfully prepared, and the grain size of these samples became larger with the increasing calcination temperature. At the same time, there was a strong interaction between CeO2 and TiO2 when the calcination temperature was around 600 °C, resulting in the formation of Ce3+ and corresponding oxygen vacancy defects on the surface. The FT-IR, FL and UV–vis results exhibited that the interaction between carbazole molecules and different carriers first decreased and then increased with the increase of calcination temperature, and corresponding fluorescence intensity and optical band gap properties of these samples showed the same change as well. The 20car/Ce/Ti-600 sample showed the lowest band gap of 2.73 eV.

Oxidation of Reduced Ceria by Incorporation of Hydrogen.

The interaction of hydrogen with reduced ceria (CeO2−x) powders and CeO2−x(111) thin films was studied using several characterization techniques including TEM, XRD, LEED, XPS, RPES, EELS, ESR, and TDS. The results clearly indicate that both in reduced ceria powders as well as in reduced single crystal ceria films hydrogen may form hydroxyls at the surface and hydride species below the surface. The formation of hydrides is clearly linked to the presence of oxygen vacancies and is accompanied by the transfer of an electron from a Ce3+ species to hydrogen, which results in the formation of Ce4+, and thus in oxidation of ceria.

Phase and microstructure formation of strip-cast Ce–Fe–B alloys for multi-phases RE-Fe-B magnets

The starting alloy has a strong influence on the processing and the magnetic properties of the sintered magnets. Aiming at the preparation of the high-performance low-cost (Nd, Ce)–Fe–B magnets, the phase constitution and microstructure of Ce–Fe–B alloy are systematically investigated in this work. The results showed that Ce2Fe14B phase coexists with CeFe2 phase in the Ce–Fe–B alloy. A fairly high proportion of 2:14:1 phase (～93.1%) and column crystals structure which is similar to that of Nd-Fe-B alloy could be obtained by regulating the composition of Ce–Fe–B alloy. Owing to the structure optimization of Ce–Fe–B alloy, the sintered magnet which possessed a microstructure of fine grains together with smooth and continuous grain boundaries could maintain the superior magnetic properties of Br = 13.1 kGs, Hcj = 7.79 kOe and (BH)max = 40.49 MGOe by the mixture of (Pr, Nd)12.75Fe80.25M1.0B6.0 and Ce17FebalM2.0B6.0 (M = Al, Cu, Ga, Nb in at.%). This work thus provides useful guideline for the preparation of Ce-doped hard magnets.

Formation of Cerium and Neodymium Isocyanides in the Reactions of Cyanogen with Ce and Nd Atoms in Argon Matrices.

Laser ablation of metallic Ce and Nd reacting with cyanogen in excess argon during codeposition at 4 K forms Ce(NC)x and Nd(NC)x for x = 1-3, which are identified from their matrix infrared spectra using cyanogen substituted with 13C and 15N. The electronic structure calculations were performed for isocyano and cyano Cd and Nd compounds for up to n = 4. The frequencies were calculated at the density functional theory level with three different functionals as well as correlated molecular orbital theory (MP2) and are consistent with the experimental assignments and the corresponding 12C/13C isotopic frequency ratios for the isocyano species. The computed frequencies for the analogous cyanide complexes are significantly higher than those for the isocyano isomers, and they are not observed in the spectra. The high spin isocyano complexes are the lowest energy structures. On the basis of the natural population analysis results, the bonding in 4CeNC and 6NdNC is essentially purely ionic with the Ce/Nd in the +I-oxidation state. The bonding for disocyano (3Ce(NC)2 and 5Nd(NC)2) and triisocyano (2Ce(NC)3 and 4Nd(NC)3) complexes is still quite ionic with the lanthanide in the +II and +III formal oxidation states, respectively. For 1Ce(NC)4, the oxidation state is best described as being between +III and +IV. Formation of 5Nd(NC)4 does not really change the electron configuration on the Nd from that in 4Nd(NC)3 and the oxidation state on the Nd remains at +III. Although Nd compounds with up to 3 NC- groups have more ionic binding than do the corresponding Ce compounds, Ce(NC)4 has more ionic binding than does Nd(NC)4. The ionic nature of isocyano Ce and Nd complexes decreases as the number of isocyano groups increases. The energetics of formation of the isocyano Ce and Nd complexes using cyanogen or CN radicals are calculated to be mostly due to exothermic processes, with the exothermicity decreasing as the number of isocyano groups increases.

Effect of the cerium (III) chloride heptahydrate on the corrosion inhibition of aluminum alloy

AbstractIn the present work, the corrosion protection of aluminum alloy AA2024‐T3 has been studied in NaCl solution, with and without the addition of cerium (III) chloride heptahydrate. The corrosion inhibitor efficiency after immersion into 10 mM NaCl, with or without 3 mM of CeCl3·7H2O at 20°C, 40°C, and 60°C was investigated. The performed quantitative tests include electrochemical techniques, such as the method of quasipotentiostatic polarization (Tafel extrapolation), cyclic polarization, and electrochemical impedance spectroscopy to determine corrosion rate (vcorr), inhibition efficiency (η %), protective ability (γ), degree of coverage (ϑ), and pitting nucleation resistance. The samples were analyzed with scanning electron microscopy and energy dispersive X‐ray analysis to evaluate and characterize the precipitates formed on the surface of aluminum samples and to determine dominant type of corrosion. The formation of Ce3+ precipitates occurred on cathodic intermetallic sites and the surface, in general, resulting in improved corrosion resistance. Tested cerium (III) chloride heptahydrate proved to be an effective inorganic corrosion inhibitor for AA2024‐T3 in chloride solution, which, by the action of cerium ions, reduced corrosion on the surface of the studied aluminum alloy.

The utilization of dye wastewater in enhancing catalytic activity of CeO2-TiO2 mixed oxide catalyst for NO reduction and dichloromethane oxidation

Waste is a misplaced resource. Herein, anionic (orange II sodium salt and Ponceau 2R) and cationic (Rhodamine B and Methylene blue) dye wastewater assisted photo-treatment (referred as DAPT) method was developed to modify sol-gel synthesized CeO2-TiO2 (CeTi) mixed oxide catalyst. Catalytic activity test results showed that both anionic and cationic dye wastewater could be used as “fuel” of photo-treatment to enhance the activity of CeTi catalyst in NO reduction and dichloromethane oxidation. Characterization and DFT calculation results revealed that DAPT process increased the amount of Ce3+ ions on CeTi samples, which could induce the formation of Ce–VO–Ti (oxygen vacancy (VO) in Ce–O–Ti short range structure). These Ce–VO–Ti defects not only could be adsorption sites for NH3, dichloromethane and oxygen, but also promoted the redox shift of Ce3++ Ti4+ ⇋ Ce4++ Ti3+ by enhancing the oxidizability of Ce4+ and Ti4+ species. Furthermore, defects changed the polarity of Ce–O and Ti–O, which was conducive to the activation of lattice oxygen. All these improvements contributed to the excellent catalytic activity of CeTi catalysts. We expected this work to be instructive on constructing structure-activity over CeO2-TiO2 based catalysts and utilizing dye wastewater.

Preparation and characterization of vitrified CeO2 coated cBN composites

Abstract The performances of vitrified cBN composites are deeply affected by the wettability of vitrified bonds on cBN particles. CeO2 coated cBN particles were successfully prepared for the further improvement of the covering and wetting of cBN by vitrified bonds. The microstructure and properties of vitrified cBN composites were characterized by scanning electron microscope (SEM), hot stage microscope (HSM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and flexural strength. Results showed that the prepared CeO2 coating on the surface of cBN was uniform and dense. Besides, the improved wettability of vitrified bonds on CeO2 coated cBN particles accompanied with the formation of Ce–O–Al and N–Si confirmed by XPS were supposed to conduce to enhancing the holding power of the vitrified bonds to cBN particles, which resulted in increasing the flexural strength of vitrified cBN composites by 9.16%. Thus, coating cBN with CeO2 was a potential and effective method to obtain vitrified cBN composites with higher flexural strength.

Cloning and In silico analysis of Casparian strip membrane domain protein (CASP) from rice

Casparian strip (CS) seals the adjacent endodermal cells to form a tight junction and thereby regulate the movement of water and salts across the endodermis. Casparian strip membrane domain proteins (CASPs) play an important role in the formation of the CS. Among the CASP proteins, the role of CASP1 was much emphasized in the making of a protein scaffold on the surface of endodermal cells that inturn leads to the formation of CS. In this study, full-length cDNA of CASP1 was cloned from the roots of salt-stressed rice cultivar ASD16 using specific primers derived from the corresponding reference gene sequence in GenBank. The cDNA fragment of 813 bp obtained through RT-PCR was cloned in an intermediary cloning vector pJET1.2. The recombinant clone carrying CASP1 was characterized by restriction analysis and sequencing. Further, in silico analysis of CASP1 revealed that it is a transmembrane protein consisting of five transverse helices as per secondary and tertiary structure analysis. 3D structure of CASP1 protein was obtained by I TASSER online server. The structure was validated using PROCHECK structural analysis tool..

Systematic investigation of composition effects on the radiation-induced attenuation mechanisms of aluminosilicate, Yb-doped silicate, Yb- and Yb,Ce-doped aluminosilicate fiber preforms [Invited

We present an original experimental approach to the investigation of radiation-induced attenuation (RIA) mechanisms in optical fiber preforms. This protocol combines thermally stimulated luminescence (TSL) measurements with the characterization of RIA annealing during TSL readouts. It is systematically applied to compositions of increasing complexity to resolve the specific role played by each dopant. Silicate, aluminosilicate, Yb-doped silicate, Yb-doped and Yb,Ce-codoped aluminosilicate preform samples are examined. Annealing processes are described in detail as a function of temperature throughout TSL readouts. The protocol reveals the temperature ranges at which trapped-carrier states forming intrinsic or dopant-related color centers are released, thus enabling the assessment of their activation energies. Metastable Ce2+ ions are proved to be formed by electron trapping under irradiation. Along with the formation of Ce3++, they play a crucial role in the RIA mitigation.

UV185+254 nm photolysis of typical thiol collectors: decomposition efficiency, mineralization and formation of sulfur byproducts.

The decomposition of toxic flotation reagents upon UV185+254 nm irradiation was attractive due to operational simplicity and no dosage of oxidants. In this work, the degradation of typical thiol collectors (potassium ethyl xanthate (PEX), sodium diethyl dithiocarbamate (SDD), O-isopropyl-N-ethyl thionocarbamate (IET) and dianilino dithiophoshoric acid (DDA)) was investigated by UV185+254 nm photolysis. The degradation efficiencies and mineralization extents of collectors were assessed. The formation of CS2 and H2S byproducts was studied, and the mechanisms of collector degradation were proposed under UV185+254 nm irradiation. The PEX, SDD and IET were decomposed with nearly 100% removal upon 75 min of UV185+254 nm irradiation. The decomposition rate constants decreased in the order SDD > PEX > IET ≫ DDA, and the DDA was the refractory collector. After 120 min of UV185+254 nm irradiation, 15−45% of carbon and 25−75% of sulfur of collectors were completely mineralized, and the mineralization extent decreased in the order PEX > SDD > IET > DDA. The percentage of gaseous sulfur (CS2 and H2S) ranged from 0.48 to 4.85% for four collectors, showing the fraction of emitted sulfur byproducts was small. The aqueous CS2 concentration increased in the first 10−20 min, and was decreased to a low level of 0.05–0.1 mg l−1 at 120 min. Two mechanisms, i.e. direct UV254 nm photolysis and indirect oxidation with free radicals, were responsible for collector decomposition in the UV185+254 nm photolysis.

Chemical response of thioaldehydes to compression between magnesium oxide surfaces: A first-principles molecular dynamics study

First-principles molecular dynamics (FPMD) simulations are used to investigate the chemical response of thioaldehyde (MeCHS) to compression between (001) surfaces of magnesium oxide (MgO), with the external load reaching values as high as 20 GPa. The results demonstrate that the application of a load transforms the MeCHS molecules into oligomers through the formation of CS, SS, and CC bonds between MeCHS monomers and through proton transfer. The application of a load facilitates the reactions by decreasing the distance between the reacting molecules. The oligomers bonded to the MgO surface through the formation of CO and SO bonds, involving an oxygen atom in the surface. Proton transfer between the oligomers and the surface was also observed. No reactions were observed to take place between the oligomers and the magnesium atoms. The formation of bonds with the oxygen atoms in the surface led to an increase in the MgO distances within the surfaces, and thus a large disruption of the surface structure. The changes in structure were found to be reversible until 18 GPa, suggesting that the MeCHS oligomers may be effective at inhibiting wear by preventing direct surface-surface contacts without introducing new sources of irreversible changes in the surface structure for a certain range of loads (until 18 GPa). As a whole, the study describes in detail the chemical behavior of MeCHS in response to compression between MgO surfaces. This information could be applied to other molecules containing sulfinyl chemical groups and other metal oxides surfaces.

Effect of Counterions on the Formation and Structures of Ce(III) and Er(III) Chloranilate Frameworks

Lanthanide-containing benzoquinoid-type frameworks have been of significant interest due to their potential for application in high-density information storage and processing, photoluminescence, and sensing. With physical and chemical properties linked to the dimensionality of coordination polymers, control of network topology is desirable in generating targeted materials. The use of various cations as templates in the synthesis of Ce(III) and Er(III) frameworks has been investigated in this study. 2D (6,3) sheets of composition [M2(can)3(H2O)6]·solvate (M = Ce or Er, can = chloranilate) are formed with the tetraalkylammonium cations, tetramethylammonium or tetrabutylammonium. When the aromatic cation 1-(diphenylmethyl)-pyridinium (DPMP+) is incorporated in the reaction mixture, anionic diamond-type networks of composition [M(can)2]− (M = Ce or Er) are formed, with the cation occupying adamantane-type cavities. The use of tetraphenylphosphonium also yields a diamond-like network but only in the case of [Ce(can)2]−. When methyltriphenylphosphonium is employed, 3D anionic networks with unusual connectivity are obtained.

Mechanochemical synthesis of the lead-free double perovskite Cs2[AgIn]Br6 and its optical properties

Hitting hard on the binary halides yields in the formation of Cs2[AgIn]Br6. The lead-free double perovskite marks, although not usable itself, a further step forward in finding sustainable and durable perovskite materials for photovoltaic applications. Cs2[AgIn]Br6 is one of the prominent examples of double perovskites materials that have been suggested to circumvent the use of lead compounds in perovskite solar cells. We herein report the successful synthesis of the material as bulk powder using a mechanochemical approach. It crystallises in an elpasolite-type structure, an ordered perovskite superstructure, with a cell parameter of a = 11.00 Å. However, the compound exhibits a relatively large optical bandgap of 2.36 eV and is unstable under illumination, which impedes its use as solar absorber material at this early stage. Still, substitution of lead and the potential of this synthesis method are promising as well as the fruitful combination of theoretical considerations with experimental materials discovery.

Utilizing a novel modifier to realize multi-refinement and optimized heat treatment of A356 alloy

Al-5Sr-8Ce master alloy was fabricated as a novel modifier, and its effect on the microstructure and tensile properties of A356 alloy was systematically investigated. The solution treatment time was also optimized based on the modification efficiency of Al-5Sr-8Ce. Results showed that Al-5Sr-8Ce mainly comprised α-Al, Al4Sr, and Al11Ce3 phases. With increasing addition of Al-5Sr-8Ce to 0.4 wt%, both the grain size and secondary dendrite arm space (SDAS) were significantly refined, while the eutectic Si morphology was modified from plate-like to small granular and rod-like morphologies. Grain growth inhibition caused by Ce segregation and the formation of Ce containing intermetallic compounds along the grain boundary was mainly responsible for the grain refinement. The excellent modification effect was attributed to the enhanced Sr modification and the inhibited growth of eutectic Si under the action of Ce. The multi-refinement of microstructure by Al-5Sr-8Ce improved the tensile properties of alloy, in particular a significant increase in elongation. However, the excess addition of Al-5Sr-8Ce (>0.4 wt%) increased the formation of coarse Ce containing intermetallic compounds, deteriorating the ultimate strength and elongation of the modified alloy. Based on the excellent Si modification by adding 0.4 wt% Al-5Sr-8Ce, the solution treatment time was successfully shortened to 90 min.

Catalytic Wet Air Oxidation (CWAO) of Phenol in a Fixed Bed Reactor Using Supported Ru and Ru‐Au Catalysts: Effect of Gold and Ce Loading

AbstractCatalysts of Ru and Ru−Au prepared by the wet impregnation and Deposition‐Precipitation methods supported on ZrO2 modified by CeO2(10 and 20 wt%) synthetized by sol‐gel method, in order to study Au and CeO2 addition effect in the catalytic wet air oxidation of phenol, carried out in an automatized continuous fixed‐bed reactor using oxygen as an oxidizing source. Characterizations of the catalysts were made by X‐ray Diffraction (XRD), Specific Surface Area (BET), X‐ray Photoelectron Spectroscopy (XPS), Transmission Electronic Microscopy (TEM), Scanning Electronic Microscopy (SEM), Ultraviolet–visible Spectroscopy (UV‐vis) and Temperature Programmed Desorption of Ammonia (NH3‐TPD). The effect of Au is reflected in the selectivity to CO2 of the catalysts Ru‐ZrO2 and Ru−Au‐ZrO2 with the increase in selectivity from 89 to 95% related to the increase in acidity which increases from 70 to 102 (μmol of NH3/ gCat). Ce loading effect in this case was important to the enhance the CO2 selectivity explained by the formation of Ce4+‐O2−‐M that could favor the oxygen transfer between the catalyst surface and the adsorbed species by a redox mechanism.

Band gap engineering, electronic state and local atomic structure of Ni doped CeO2 nanoparticles

In cerium dioxide (CeO2) as semiconductor compound, the tuning of band gap energy is a pivotal feature for visible light applications. In this report, nanoparticles (NPs) of Ce1 − xNixO2 (0.0 ≤ x ≤ 0.10) were synthesized through co-precipitation route. The structural, electronic state and optical band gap were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), near edge X-ray absorption fine structure (NEXAFS) spectroscopy, Raman scattering and UV–Vis spectroscopy. XRD results revealed the single-phase nanocrystalline behavior of CeO2 with cubic fluorite structure. The electronic configuration of the samples, probed via NEXAFS spectra at Ce M5, 4 edges, demonstrated that the cerium exists in Ce4+ and Ce3+ mixed valence states. The formation of Ce3+ ions in the vicinity of oxygen vacancies (Ov) were assessed also via Raman scattering and XANES spectra at Ce L3 edge. The estimated concentrations of Ce3+ were increased from 6 to 13% as the Ni content increase from 0 to 10% respectively. Here, the inclusion of Ni2+ ions into CeO2 network induced additional Ov and simultaneously reduced the optical band gap from 3.9 eV for pure CeO2 to 2.6 eV for 10% Ni doped CeO2 NPs. Therefore, the oxygen loss population seem to be responsible for the band gap reduction. The role of Ov for creating profound donor band near the conduction band and narrowing the band gap energy were discussed.

Cerium(III) and cerium(IV) nitrate complexes of trialkylphosphine oxides

The reactions of ammonium cerium(IV) nitrate, (NH4)2Ce(NO3)6 (CAN) with trialkylphosphine oxides, R3PO (R = Et, iPropyl, nBu3, iBu3PO, tBu3PO, Cy3PO (Cy = cyclohexyl) and Oct3PO (Oct = n-octyl)) have been investigated by 31-P NMR spectroscopy in a variety of conditions. Reactions with acetone solutions of excess of CAN and R3PO and of solid CAN with chloroform solutions of R3PO and aqueous solutions of CAN with chloroform solutions of R3PO led to the observation of Ce(NO3)4(R3PO)2. 31-P NMR spectroscopy and conductimetric titration of acetone solutions of CAN with R3PO confirm the initial reactions is the formation of Ce(NO3)4(R3PO)2 (R = Et, Bu, Cy, Oct) followed by a slower reaction to form the ionic [Ce(NO3)3(R3PO)3][NO3]. The isolation of pure complexes has not proved possible in most cases but crystals suitable for x-ray analysis were extracted in some instances. The structures of the Ce(IV) complexes [Ce(NO3)4(Cy3PO)2] and [Ce(NO3)3(Et3PO)3][NO3] and the related Ce(III) complexes [Ce(NO3)3(Cy3PO)3] and [Ce(NO3)3(H2O)3(Et3PO)] are reported.

Synthesis of Ce-doped magnetic biochar for effective Sb(V) removal: Performance and mechanism

A novel Ce-doped magnetic biochar was successfully synthesized by chemical co-precipitation (Ce/FeCP-BC) and solvothermal methods (Ce/FeST-BC) for efficient Sb(V) adsorption. The Ce/FeCP-BC exhibited a high adsorption capacity of 25.0 mg/g, which was two times and one order of magnitude higher than that of Ce/FeST-BC and un-doped BC, respectively. The excellent adsorption performance of Ce/FeCP-BC maintained over a wide pH range or in the presence of coexisting anions. The adsorption results indicated that co-precipitation method was superior to solvothermal method and Ce oxide was the main contribution to Sb(V) adsorption enhancement. The combined results of TEM, XRD, FTIR and XPS revealed that Ce atom was successfully doped into the Fe3O4 structure and abundant hydroxyl groups were formed on the surface of Ce/FeCP-BC. The magnetic performance decreased after Ce doping, but Ce/FeCP-BC still showed good separation potential. Based on the results of batch experiments and physiochemical analyses, the underlying mechanisms controlling Sb(V) adsorption on Ce/FeCP-BC involved the inner-sphere surface complexation, hydrogen bonding, electrostatic attraction and ligand exchange. Among them, the ligand exchange and the formation of Ce–O–Sb complex were the main contributions to the significant Sb(V) adsorption increment on Ce/FeCP-BC. All the results implied that Ce/FeCP-BC could be used as a promising adsorbent for antimonate decontamination.

CeFe-Based Bead Nanocomposites as Catalysts for Oxidation of Ethylbenzene Reaction

Oxides with good catalytic performances and more selectivity to valuable chemicals attract numerous research interests for the oxidation of hydrocarbon fuels. Taking advantage of the nanocasting route, CeFe-based nanocomposites were prepared and characterized to achieve superior stability in the oxidation of cyclic compounds. Adding a third metal (Me = Ni2+, Mn2+/Mn3+ or Co2+/Co3+) to the CeFe-based oxide helped the formation of Ce3+/Ce4+, Fe2+/Fe3+ and active couples in the ternary nanocomposites. The solids having a spherical morphology and good textural properties enabled the formation of promising ternary oxide catalysts for the oxidation of ethylbenzene compared with those of binary and single monoxide nanocomposites. The close contact among the Ce3+/Ce4+ and Fe2+/Fe3+ pairs with Ni2+ species provided the formation of a highly stable CeFeNi catalyst with enhanced performance in the oxidation of cyclic compounds such as ethylbenzene, styrene and benzyl alcohol substrates.