Structural Characterization of Nanosized CeO2−SiO2, CeO2−TiO2, and CeO2−ZrO2 Catalysts by XRD, Raman, and HREM Techniques

Bioinspired Cerium Nanozyme Microenvironment Regulation for Efficient Dephosphorylation and Detection of Organophosphorus Pesticides

Mimicking the structure of natural enzyme active sites offers a promising strategy for the rational design of nanozymes. However, this biomimetic approach predominantly focuses on replicating the configuration of the metal active center in natural enzymes, often overlooking the critical influence of the catalytic site's microenvironment. Here, inspired by the active center and coordination microenvironment of natural organophosphorus hydrolase (OPH), Ce2O2CN2/NC, a novel cerium-based nanozyme is first reported to mimic OPH. In Ce2O2CN2/NC, Ce species serve as active sites, while the adjacent N site ([N═C═N]2-) functions as a general base, mimicking histidine in natural enzymes to facilitate the hydrolysis process. Using paraoxon as a model target, Ce2O2CN2/NC demonstrates rapid dephosphorylation of phosphotriester across a wide range of temperatures and pH values, significantly outperforming natural OPH and CeO2 nanoparticles. The systematic experiments and theoretical calculations reveal the underlying mechanisms responsible for the enhanced OPH-mimicking performance. Capitalizing on its phosphatase-like activity, Ce2O2CN2/NC nanozyme is successfully employed to develop a colorimetric biosensor for the rapid and selective detection of organophosphorus pesticides. This study holds great promise in developing efficient nanozymes and broadens the range of Ce-based nanozymes.

Diabetic wound healing function of PCL/cellulose acetate nanofiber engineered with chitosan/cerium oxide nanoparticles

The use of cerium oxide nanoparticles (CeO2NPs) in diabetic wound repair substances has shown promising results. Therefore, the study was conducted to introduce a novel nano-based wound dressing containing chitosan nanoparticles encapsulated with green synthesized cerium oxide nanoparticles using Thymus vulgaris extract (CeO2-CSNPs). The physical properties and structure of the nanoparticles were analyzed using XRD, DLS, FESEM and FTIR techniques. The electrospun PCL/cellulose acetate-based nanofiber was prepared and CeO2-CSNPs were integrated on the PCL/CA membrane by electrospraying. The physicochemical properties, morphology and biological characteristics of the electrospun nanocomposite were evaluated. The results showed that the nanocomposite with 0.1 % CeO2-CSNPs exhibited high antibacterial performance against S. aureus (<58.59 µg/mL). The PCL/CA/CeO2-CSNPs nanofiber showed significant antioxidant activity up to 89.59 %, cell viability improvement, and cell migration promotion up to 90.3 % after 48 h. The in vivo diabetic wound healing experiment revealed that PCL/CA/CeO2-CSNPs nanofibers can significantly increase the repair rate of diabetic wounds by up to 95.47 % after 15 days. The results of this research suggest that PCL/CA nanofiber mats functionalized with CeO2-CSNPs have the potential to be highly effective in treating diabetes-related wounds.

Catalytic CO Oxidation on the Cu+-Ov-Ce3+ Interface Constructed by an Electrospinning Method for Enhanced CO Adsorption at Low Temperature

It is crucial to eliminate CO emissions using non-noble catalysts. Cu-based catalysts have been widely applied in CO oxidation, but their activity and stability at low temperatures are still challenging. This study reports the preparation and application of an efficient copper-doped ceria electrospun fiber catalyst prepared by a facile electrospinning method. The obtained 10Cu-Ce fiber catalyst achieved complete CO oxidation at a temperature as low as 90 °C. However, a reference 10Cu/Ce catalyst prepared by the impregnation method needed 110 °C to achieve complete CO oxidation under identical reaction conditions. Asymmetric oxygen vacancies (ASOV) at the interface between copper and cerium were constructed, to effectively absorb gas molecules involved in the reaction, leading to the enhanced oxidation of CO. The exceptional ability of the 10Cu-Ce catalyst to adsorb CO is attributed to its unique structure and surface interaction phase Cu+-Ov-Ce3+, as demonstrated by a series of characterizations and DFT calculations. This novel approach of using electrospinning offers a promising technique for developing low-temperature and non-noble metal-based catalysts.

Enhanced Antioxidant Ability of PEG-Coated Ce0.5Zr0.5O2-Based Nanofluids for Scavenging Hydroxyl Radicals

The antioxidant therapy to preserve residual hearing is relatively recent, and the search for effective antioxidants is still ongoing. Though nanoceria has shown promising radical-scavenging capability, improving its antioxidant ability and the dispersion stability of its nanofluid, which is critical to the desired site, i.e., cochlea, still remains a major challenge. The objective of the present work is to study the radical-scavenging capability of poly(ethylene glycol) (PEG)-coated CeO₂ and Ce_0.5Zr_0.5O₂ nanoparticles in water and the biologically relevant fluid (PBS buffer). Nanoparticles in the size range of 4.0-9.0 nm are synthesized using the coprecipitation method and characterized using suitable techniques. The scavenging and dispersion stability of the synthesized nanofluid are analyzed using a UV-vis spectrophotometer. It is found that the addition of PEG during the synthesis process promoted the generation of finer nanoparticles with a narrow size distribution and the doping of zirconium produced a large number of defects in the crystallite structure. The PEG coating over the nanoparticles improved the dispersion stability of nanofluids without affecting their surface reactivity, and it is found to be 94 and 80% in water and PBS, respectively, at 500 μM and 60 min, which is maintained till 90 min. The highest scavenging of hydroxyl radicals by PEG-coated Ce_0.5Zr_0.5O₂ is found to be 60%, which is significantly superior to that of CeO₂. The scavenging capability is found to be increased with the concentration of nanoparticles, showing the best scavenging activity at 190 and 150 μM for PEG-coated CeO₂ and Ce_0.5Zr_0.5O₂, respectively, and the scavenging in water is at par with that of PBS, indicating that these nanoparticles are suitable to be used in sites where a biologically relevant fluid is present, e.g., the cochlea. It is proposed that PEG-coated Ce_0.5Zr_0.5O₂ having an average size of ∼ 4 nm can be a potential antioxidant in relevant biomedical applications.

Engineering Multidefects on Cex Si1- x O2- δ Nanocomposites for the Catalytic Ozonation Reaction

Herein, it is shown that by engineering defects on Ce_x Si_{1- x} O_{2- δ} nanocomposites synthesized via flame spray pyrolysis, oxygen vacancies can be created with an increased density of trapped electrons, enhancing the formation of reactive oxygen species (ROSs) and hydroxyl radicals in an ozone-filled environment. Spectroscopic analysis and density functional theory calculations indicate that two-electron oxygen vacancies (O_V ⁰ ) or peroxide species, and their degree of clustering, play a critical role in forming reactive radicals. It is also found that a higher Si content in the binary oxide imposes a high O_V ⁰ ratio and, consequently, higher catalytic activity. Si inclusion in the nanocomposite appears to stabilize the surface oxygen vacancies as well as increase the reactive electron density at these sites. A mechanistic study on effective ROSs generated during catalytic ozonation reveals that the hydroxyl radical is the most effective ROS for organic degradation and is formed primarily through H₂ O₂ generation in the presence of the O_V ⁰ . Examining the binary oxides offers insights on the contribution of oxygen vacancies and their state of charge to catalytic reactions, in this instance for the catalytic ozonation of organic compounds.

Influence of phosphorus on the NH3-SCR performance of CeO2-TiO2 catalyst for NOx removal from co-incineration flue gas of domestic waste and municipal sludge

Domestic waste and municipal sludge are two major solid hazardous substances generated from human daily life. Co-incineration technology is regarded as an effective method for the treatment of them. However, the emitted NO_x-containing exhaust with high content of phosphorus should purified strictly. CeO₂-TiO₂ is a promising catalyst for removal of NO_x by NH₃-SCR technology, but the effect of phosphorous in the exhaust is ambiguous. Therefore, the effect of phosphorus on NH₃-SCR performance and physicochemical properties of CeO₂-TiO₂ catalyst was investigated in our present work. It was found that phosphorus decreased the NH₃-SCR activity below 300 °C. Interestingly, it suppressed the formation of NO_x and N₂O caused by NH₃ over-oxidation above 300 °C. The reason might be that phosphorus induced Ti⁴⁺ to migrate from CeO₂-TiO₂ solid solution and form crystalline TiO₂, which led to the destruction of Ti-O-Ce structure in the catalyst. So, the transfer of electrons between Ti and Ce ions, the relative contents of Ce³⁺, and surface adsorbed oxygen, as well as the redox performance were limited, which further inhibited the over-oxidation of NH₃. In addition, phosphorus weakened the NH₃ adsorption on Lewis acid sites and the adsorption performance of NO + O₂, while increased the Brønsted acid sites. Finally, the reaction mechanism over CeO₂-TiO₂ catalyst did not change after introducing phosphorus, L-H and E-R mechanisms co-existed on the surface of the catalysts.

Transformation of Highly Stable Pt Single Sites on Defect Engineered Ceria into Robust Pt Clusters for Vehicle Emission Control

Engineering surface defects on metal oxide supports could help promote the dispersion of active sites and catalytic performance of supported catalysts. Herein, a strategy of ZrO₂ doping was proposed to create rich surface defects on CeO₂ (CZO) and, with these defects, to improve Pt dispersion and enhance its affinity as single sites to the CZO support (Pt/CZO). The strongly anchored Pt single sites on CZO support were initially not efficient for catalytic oxidation of CO/C₃H₆. However, after a simple activation by H₂ reduction, the catalytic oxidation performance over Pt/CZO catalyst was significantly boosted and better than Pt/CeO₂. Pt/CZO catalyst also exhibited much higher thermal stability. The structural evolution of Pt active sites by H₂ treatment was systematically investigated on aged Pt/CZO and Pt/CeO₂ catalysts. With H₂ reduction, ionic Pt single sites were transformed into active Pt clusters. Much smaller Pt clusters were created on CZO (ca. 1.2 nm) than on CeO₂ (ca. 1.8 nm) due to stronger Pt-CeO₂ interaction on aged Pt/CZO. Consequently, more exposed active Pt sites were obtained on the smaller clusters surrounded by more oxygen defects and Ce³⁺ species, which directly translated to the higher catalytic oxidation performance of activated Pt/CZO catalyst in vehicle emission control applications.

Identification of refractory zirconia from catalytic converters in dust: An emerging pollutant in urban environments

Using catalytic converters is one of the most effective methods to control vehicle emissions. A washcoat of cerium oxide-zirconia (CeO₂-ZrO₂) has been used to enhance the performance of the catalytic converter device. To date, the prevalence of this material in the environment has not been assessed. In this study, we present evidence of the existence of inhalable zirconia in urban dust. Samples of the washcoat, exhaust pipe, topsoil, and road dust were analyzed by X-ray fluorescence, X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, photoluminescence (PL) spectroscopy, and thermally stimulated luminescence (TSL). The results showed a CeO₂-ZrO₂ phase separation after sintering. This causes the emission of ZrO₂, CeO₂, and CeZrO_x particles smaller than 1 μm, which can likely reach the alveolar macrophages in the lungs. The Ce-Zr content in road dust exceeds geogenic levels, and a significant correlation of 0.87 (p < 0.05) reflects a common anthropic source. Chronic exposure to such refractory particles may result in the development of non-occupational respiratory diseases. The inhalable crystalline compounds emitted by vehicles are a significant environmental health hazard, revealing the need for further investigation and assessment of zirconia levels generated by automobiles in urban areas worldwide.

CO2-assisted ethane oxidative dehydrogenation over MoOx catalysts supported on reducible CeO2–TiO2

Supported MoOx catalysts on mixed CeO2–TiO2 were investigated for the oxidative dehydrogenation of ethane (ODHE) using CO2 as a mild oxidant. The reducibility of the support and nature of MoOx affect the relative dehydrogenation pathways.

Silicotungstic acid modified CeO2 catalyst with high stability for the catalytic combustion of chlorobenzene

The catalysts' redox capacity and surface acidity was important during the catalytic combustion of chlorobenzene (CB). CeO₂ showed great attractiveness due to its high oxygen storage capacity. Furthermore, the increase of acidity on the catalyst surface could improve the resistance to the chlorine poisoning. In this work, the silicotungstic (HSiW) modified CeO₂ catalysts prepared by four cerium salts and exhibited the different morphologies and catalytic activity. The HSiW modified CeO₂ catalyst prepared by Ce(CH₃COO)₃ (Cat-A) exhibited the best catalytic activity due to its abundant surface weak acid sites, more Ce³⁺ species and surface adsorption oxygen. The HSiW mainly located on the CeO₂ (111) planes of the Cat-A, which was conducive to redox property of CeO₂, thus promoting the deep oxidation of CB. Meanwhile the redox ability together with the weak acidity influenced the catalytic efficiency at low temperature. And the redox ability played a major role at high temperature. In addition, the Cat-A still possessed high stability and water resistance and maintained high activity after continuous catalytic oxidation of CB at 235 and 295 °C for 100h, exhibiting the possibility of industrial application.

Conversion of syngas into light olefins over bifunctional ZnCeZrO/SAPO-34 catalysts: regulation of the surface oxygen vacancy concentration and its relation to the catalytic performance

Surface oxygen vacancies can improve the formation of methanol intermediates and promote their evolution into olefin products for syngas-to-olefins over Zn_0.5CeZrO_x/SAPO-34.

Simultaneous catalytic reduction of p-nitrophenol and hydrogen production on MIL-101(Fe)-based composites

MIL-101(Fe)-based composite materials and their application for the generation of H₂ by the catalytic reduction of nitro organics are reported in this study.

Altering the influence of ceria oxygen vacancies in Ni/CexSiyO2 for photothermal CO2 methanation

While the benefit of CeO₂ surface oxygen vacancies for CO₂ methanation is well established, their role under photothermal conditions has not been probed in depth.

Catalytic peroxidation of acrylic acid from aqueous solution incorporated with highly active La0.5Sr0.5BO3 (B=Cu, Fe and Ni) perovskite-like catalysts

In the current study, catalytic behaviour of La_0.5Sr_0.5BO₃ (B=Cu, Fe and Ni) perovskite-like catalysts synthesized by sol-gel method were examined in catalytic peroxidation of acrylic acid as a model organic compound and further characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The effect of various parameters such as catalyst dose, H₂O₂/acrylic acid molar ratio, temperature, pH and initial acrylic acid concentration on acrylic acid and COD removal was studied. The maximum acrylic acid and COD removal of 86.79% and 71.57% were observed at optimum operating conditions (e.g., La_0.5Sr_0.5CuO₃ catalyst dose = 600 mg/L, stoichiometric molar ratio of H₂O₂/acrylic acid = 1.5, pH = 3, temperature 65 °C and reaction time = 3 h). The ROS scavenging studies were performed to identify in-situ generated reactive oxidant species, e.g., hydroxyl radicals (^•OH), superoxide radicals (O₂ ^•־) and singlet oxygen (¹O₂) and treated with their respective quencher during catalytic peroxidation of acrylic acid. Acrylic acid removal kinetics was performed by first order and Langmuir-Hinshelwood kinetic models. The plausible degradation mechanism was proposed based on intermediates identified by GC-MS analysis during catalytic peroxidation of acrylic acid.

Atomic-scale insights into electro-steric substitutional chemistry of cerium oxide

Cerium oxide (ceria, CeO2) is one of the most promising mixed ionic and electronic conducting materials. Previous atomistic analysis has widely covered the effects of substitution on oxygen vacancy migration. However, an in-depth analysis of the role of cation substitution beyond trivalent cations has rarely been explored. Here, we investigate soluble monovalent (Li+, Na+, K+, Rb+), divalent (Fe2+, Co2+, Mn2+, Mg2+, Ni2+, Zn2+, Cd2+, Ca2+, Sr2+, Ba2+), trivalent (Al3+, Fe3+, Sc3+, In3+, Lu3+, Yb3+, Y3+, Er3+, Gd3+, Eu3+, Nd3+, Pr3+, La3+) and tetravalent (Si4+, Ge4+, Ti4+, Sn4+, Hf4+, Zr4+) cation substituents. By combining classical simulations and quantum mechanical calculations, we provide an insight into defect association energies between substituent cations and oxygen vacancies as well as their effects on the diffusion mechanisms. Our simulations indicate that oxygen ionic diffusivity of subvalent cation-substituted systems follows the order Gd3+ > Ca2+ > Na+. With the same charge, a larger size mismatch with the Ce4+ cation yields a lower oxygen ionic diffusivity, i.e., Na+ > K+, Ca2+ > Ni2+, Gd3+ > Al3+. Based on these trends, we identify species that could tune the oxygen ionic diffusivity: we estimate that the optimum oxygen vacancy concentration for achieving fast oxygen ionic transport is ≈2.5% for GdxCe1-xO2-x/2, CaxCe1-xO2-x and NaxCe1-xO2-3x/2 at 800 K. Remarkably, such a concentration is not constant and shifts gradually to higher values as the temperature is increased. We find that co-substitutions can enhance the impact of the single substitutions beyond that expected by their simple addition. Furthermore, we identify preferential oxygen ion migration pathways, which illustrate the electro-steric effects of substituent cations in determining the energy barrier of oxygen ion migration. Such fundamental insights into the factors that govern the oxygen diffusion coefficient and migration energy would enable design criteria to be defined for tuning the ionic properties of the material, e.g., by co-substitutions.

Gas phase sulfation of ceria-zirconia solid solutions for generating highly efficient and SO2 resistant NH3-SCR catalysts for NO removal

A series of ceria-zirconia solid solutions (Ce_xZr_1-xO₂) were prepared by co-precipitation method and then sulfated with SO₂ + O₂ at 200 °C. Subsequent testing with the selective catalytic reduction of NO by NH₃ (NH₃-SCR) showed that the activity of the sulfated Ce_xZr_1-xO₂ catalysts oxide catalysts exhibited a volcano-type tendency with increasing Zr content. Furthermore, the sulfated Ce_0.6Zr_0.4O₂ catalyst showed the most desirable NH₃-SCR activity at 250-300 °C, and exhibited much better SO₂ resistance at 250 °C. Detailed characterization results demonstrated that Ce_0.6Zr_0.4O₂ could adsorb more surface sulfate species and then produce more stable acid sites than pure CeO₂ at 200 °C. After sulfation treatment, more Ce³⁺ and oxygen vacancies were formed on the surface of Ce_0.6Zr_0.4O₂. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) experiments suggested that the nitrates species deposited on the surface of as-prepared Ce_0.6Zr_0.4O₂, which showed no reactivity, could barely deposit on the same sample after sulfation. While, the sulfated Ce_0.6Zr_0.4O₂ had more reactive acid sites to participate in the NH₃-SCR and the reaction proceeded via Eley-Rideal mechanism. This work proved that sulfation treatment could be used in designing an efficient cerium-zirconium based NH₃-SCR catalyst with great application prospect.

Short period sinusoidal thermal modulation for quantitative identification of gas species

The field of chemical (gas) sensing has witnessed an unprecedented increase in device sensitivity with single molecule detection now becoming a reality. In contrast to this, the ability to distinguish or discriminate between gas species has lagged behind. This is problematic and results in a high rate of false alarms. Here, we demonstrate a short period sinusoidal thermal modulation strategy to quantitatively and rapidly identify two industrially relevant gases (hydrogen sulfide (H₂S) and sulfur dioxide (SO₂)) by using a single semiconducting metal oxide sensor device. By applying sinusoidal heating voltages with a fixed short period, we were able to simultaneously obtain distinct patterns of dynamic responses. These characteristic patterns were adopted to build and validate a gas recognition library. Our approach does not rely on large-scale sensor arrays and complex algorithms and is amenable for real-time and low-power gas monitoring.

Dual catalyst system for selective vinyl chloride production via ethene oxychlorination

A dual system featuring ZrO₂-supported CeO₂ and Ca-doped Al₂O₃ catalysts enables the direct production of vinyl chloride via ethene oxychlorination.

Comparative study on the catalytic activity of Fe-doped ZrO2 nanoparticles without significant toxicity through chemical treatment under various pH conditions

Despite advances in the construction of catalysts based on metal oxide nanoparticles (MO NPs) for various industrial, biomedical, and daily-life applications, the biosafety concerns about these NPs still remain. Recently, the need to analyze and improve the safety of MO NPs along with attempts to enhance their catalytic performance has been strongly perceived. Here, we prepared multiple variants of Fe-doped zirconium oxide (Fe@ZrO₂) NPs under different pH conditions; then, we assessed their toxicity and finally screened the variant that exhibited the best catalytic performance. To assess the NP toxicity, the prepared NPs were introduced into three types of human cells originally obtained from different body parts likely to be most affected by NPs (skin, lung, and kidney). Experimental results from conventional cellular toxicity assays including recently available live-cell imaging indicated that none of the variants exerted severe negative effects on the viability of the human cells and most NPs were intracellular localized outside of nucleus, by which severe genotoxicity is unexpected. In contrast, Fe@ZrO₂ NPs synthesized under a basic condition (pH = 13.0), exhibited the highest catalytic activities for three different reactions; each was biochemical (L-cysteine oxidation) or photochemical one (4-chlorophenol degradation and OH radical formation with benzoic acid). This study demonstrates that catalytic Fe@ZrO₂ NPs with enhanced activities and modest or insignificant toxicity can be effectively developed and further suggests a potential for the use of these particles in conventional chemical reactions as well as in recently emerging biomedical and daily-life nanotechnology applications.

The relationship between the chemical state of Pd species and the catalytic activity for methane combustion on Pd/CeO2

Three Pd/CeO₂ catalysts are synthesized by reduction-deposition and an impregnation method (IMP) to clarify how the chemical state of Pd influences the catalytic performance for CH₄ combustion.

Non-Noble Metal Oxide Catalysts for Methane Catalytic Combustion: Sonochemical Synthesis and Characterisation

The aim of this study was to obtain nanocrystalline mixed metal-oxide–ZrO₂ catalysts via a sonochemically-induced preparation method. The effect of a stabiliser’s addition on the catalyst parameters was investigated by several characterisation methods including X-ray Diffraction (XRD), nitrogen adsorption, X-ray fluorescence (XRF), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and µRaman. The sonochemical preparation method allowed us to manufacture the catalysts with uniformly dispersed metal-oxide nanoparticles at the support surface. The catalytic activity was tested in a methane combustion reaction. The activity of the catalysts prepared by the sonochemical method was higher than that of the reference catalysts prepared by the incipient wetness method without ultrasonic irradiation. The cobalt and chromium mixed zirconia catalysts revealed their high activities, which are comparable with those presented in the literature.

Mixed-phase TiO2 photocatalysis: correlation between phase composition and photodecomposition of water pollutants

In most cases, the combination of both anatase (up to 80%) and rutile (up to 20%) structures in a mixed-phase TiO2 semiconductor results in a better photocatalytic performance compared to the pure phase. The improvement from anatase to rutile is brought about by the enhanced transportation of photogenerated electrons. This consequently results in improved efficiency of the photoelectric and photocurrent conversion. This review highlights the effects of the morphology, particle size, and crystal structure of mixed-phase TiO2 toward the photodegradation of water pollutants. It was demonstrated that the synergistic effect between anatase and rutile TiO2 due to the interfacial electron transfer from rutile to anatase improved the photocurrent as well as the overall conversion efficiency of the anatase photoanodes. The morphologies of mixed-phase TiO2 also contributed to the final photodegradation properties. The charge and electron transfer of mixed-phase TiO2 improved the 1D structure. This consequently enables photodegradation at the visible light range.

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.

Effect of the calcination temperature of cerium–zirconium mixed oxides on the structure and catalytic performance of WO3/CeZrO2 monolithic catalyst for selective catalytic reduction of NOx with NH3

The calcined temperature of the carrier obviously affected SCR activity of catalysts, WO₃/Ce_0.68Zr_0.32O₂-500 showed the best low-temperature NH₃-SCR activity due to its more Lewis acid sites and stronger redox property.