CeO2 Content Research Articles

Selective catalytic oxidation of DMF over Cu-Ce/H-MOR by modulating the surface active sites

Selective catalytic oxidation of the hazardous DMF exhaust gas presents a significant challenge in balancing oxidation activity and products selectivity (CO, NOx, N2, etc.). It is found that Cu/H-MOR demonstrates superior performance for DMF oxidation compared to CuO on other supports (γ-Al2O3, HY, ZSM-5) in terms of product selectivity and stability. The geometric and electronic structures of CuO active sites in Cu/H-MOR have been regulated by CeO2 promoter, leading to an increase in the ratio of active CuO (highly dispersed CuO and Cu+ specie). As a result, the oxidation activity and stability of the Cu/H-MOR catalyst were enhanced for DMF selective catalytic oxidation. However, excessive CuO or CeO2 content led to decreased N2 selectivity due to over-high oxidation activity. It is also revealed that Ce3+ species, active CuO species, and surface acid sites play a critical role in internal selective catalytic reduction reaction during DMF oxidation. The 10Cu-Ce/H-MOR (1/4) catalyst exhibited both high oxidation activity and internal selective catalytic reduction activity due to its abundance of active CuO specie as well as Ce3+ species and surface acid sites. Consequently, the 10Cu-Ce/H-MOR (1/4) catalyst demonstrated the widest temperature window for DMF oxidation with high N2 selectivity. These findings emphasize the importance of surface active sites modification for DMF selective catalytic oxidation.

Efficient electrocatalytic reduction of nitrate to ammonia using Cu–CeO2 solid solution

Electrocatalytic nitrate reduction reaction (EC-NITRR) is expected to replace Haber-Bosch process for green ammonia (NH3) production. Currently, many catalysts often result in low NH3 yields and low faraday efficiencies due to the lack of active sites. In this study, Cu-doped CeO2 solid solution catalyst was prepared for EC-NITRR using transition metal ions doping. The addition of Cu significantly improved the oxygen vacancy (Ov) concentration of CeO2 and provided more active sites for NO3− catalysis. Meanwhile, the internal charge transfer capability and surface catalytic kinetics of the catalyst are enhanced by the excellent redox capability of Ce3+ and Cu+. Compared with bare CeO2, the NH3 yield of 7% Cu–CeO2 increased by 1.88 times. This work provides new ideas for the design of green and efficient catalysts for EC-NITRR by identifying the role of Cu in the mechanism of doping regulation of CeO2.

Amorphization transition and electrical properties of La2−xCexCuO4 polycrystalline materials

In contrast to crystals, amorphous materials exhibit distinctive properties and applications due to their unique electronic structure and surface energy. Moreover, the amorphous modification of crystalline materials also results in numerous notable and unique properties. In this study, we propose the amorphous modification of polycrystal La2CuO4 with CeO2, examining the composition of the two phases and changes in the crystal structure. Our findings indicate that the degree of ordering of the La2CuO4 phase significantly decreases as the CeO2 content increases, leading to a resistivity increase in 3–4 orders of magnitude. Furthermore, within the 40–400 K, the transition of the Efros–Shklovskii variable range hopping (E–S VRH) transport mechanism between localized states to the Mott 3D VRH and the crossover around 230 K is observed. The method presented here has great potential in modifying polycrystalline materials by using amorphization to make a sudden increase in resistivity.

Polyvinyl alcohol-encapsulated cerium oxide nanospheres composite nanofiber membrane for enhanced antioxidant and antibacterial applications☆

Cerium oxide (CeO2) has attracted much attention in recent years owing to its reversible switch ability in Ce3+/Ce4+ redox to produce improved antioxidation properties for biomedical applications. Here, we report to embed the CeO2 nanospheres into the organic polymer network using electrostatic spinning technology to prepare polyvinyl alcohol (PVA)-encapsulated CeO2 nanospheres composite nanofibrous membranes (PVA-CeO2) for the first time, which is beneficial to improving the dispersion and biocompatibility of CeO2 nanosphere without altering the original antioxidant properties of CeO2. Detailed characterization of the as-prepared composite nanofibrous membranes reveals that CeO2 was successfully introduced into the PVA fibers with strong interactions, thus enhancing the thermal stability and fracture toughness of the nanofibers. As a result, PVA-CeO2 exhibits superior UV shielding performance, antioxidant performance and bacteriostatic performance. Meaningfully, PVA-CeO2 has strong absorbance in both UVA and UVB bands when the CeO2 concentration in the nanofiber membrane reaches 1.5 wt%, and shows an excellent scavenging effect on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals with a scavenging rate of 86.52%. Moreover, the Kirby-Bauer (K-B) method of agar diffusion test further confirms that PVA-CeO2 has antimicrobial ability against three types of representative strains, including Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli) and fungi (Candida albicans). Importantly, no obvious cytotoxicity is observed for PVA-CeO2 even though the amount of embedded CeO2 nanosphere reaches as high as 1.5 wt%. This study reveals new avenues for improving the future smart design of CeO2-based nanofiber membrane composite materials for biological antioxidants.

New trends in gamma ray shielding features of silicate tellurite glass using cerium oxide nanoparticles reinforcement (xCeO2-20SiO2-(80-x)TeO2); (x = 10, 15, 20 and 25)

In this work, we investigated the gamma ray shielding features of xCeO2-0.2SiO2-(80-x)TeO2 glass using DFT and phy-x/PSD approach. Optimization of the silicate-tellurite glass samples were done by adding CeO2 in W% of 0.10, 0.15, 0.20 and 0.25 % respectively. Based on the obtained results, the density and gamma ray shielding properties of the CeSiTe glass increased with W% of CeO2 nanoparticles. Reduction in the oxygen parking fraction from 74.240 to 65.012 g/atom when CeO2 concentration was increased from 0.10 to 0.25 W% confirmed the loose structure of the CeSiTe glass. With respect to photon attenuation parameters, the lowest value of half value layer (3.20 cm) by CeSiTe4 revealed its superior attenuation power than CeSiTe1 whose half value layer is 7.74 cm. As observed, photoelectric effect dominated the range 0–40 KeV, Compton scattering is dominant between 27.2 and 100 KeV while pair production dominated energies greater than 1.5 MeV. We also observed that the HVL of the presently studied CeSiTe glass is comparable to that of lead silicate glasses (xSiO2-(1-x)PbO2). Generally, the obtained attenuation parameters were also found to be similar to that of lead silicate glass, hence CeSiTe glass can be good alternative to lead silicate glasses for gamma ray shielding.

Influence of Chromium Carbide-Derived Carbon Support and Ceria Nanocrystals on Pt–CeO2/C Catalysts for Fuel Cell Applications

The influence of different synthesis parameters on CeO2 and Pt nanoparticle (NP) deposition on Ketjenblack carbon (C(KB)) was examined. The Pt NP diameter (3.1–4.1 nm) was not influenced by CeO2 synthesis parameters. The CeO2 NPs synthesized using ultrasound sonication contribute to a better durability of the Pt–CeO2/C against CO poisoning. In contrast, CeO2 synthesized using the microwave heating method contributes to better methanol oxidation reaction (MOR) activity at low electrode potential. Synthesis parameters of CeO2 and Pt NPs developed for the C(KB)-based catalysts were applied for C(Cr3C2)-based catalysts. The Pt NP diameter of C(Cr3C2)-based catalysts was slightly higher (7.2 nm) as some Pt NPs were agglomerated. The C(Cr3C2) support facilitates the MOR and CO stripping, especially in the case of the Pt/C on C(Cr3C2) support. The MOR activity at 0.85 V of Pt NPs on the C(Cr3C2) support is as good as the MOR activity for the best Pt–CeO2 on the C(KB) support. The C(Cr3C2) support also improves the CO removal from the Pt surface. All the synthesized catalysts had better MOR activity than the commercial Pt/C(Vulcan) catalyst. The oxygen reduction reaction activity of Pt–CeO2/C catalysts with higher CeO2 content synthesized with the microwave heating method was very good.

Revealing the Enhanced Visible-light-driven Photocatalytic Activity of In2S3/CeO2 Heterojunction: Bandgap Structure Analysis and Active Radicals Determination

Background: The widespread presence of persistent organic pollutants, such as dyes in effluent from printing and textile industries, poses a significant threat to aquatic life and human health. Photocatalytic degradation is widely recognized as a promising technology to address this pollution crisis. The efficiency of photocatalysis is intricately tied to both the active radicals and the band structure of the catalyst. These factors play a crucial role in governing the photodegradation of dye molecules. Methods: In2S3/CeO2 heterojunctions were synthesized using an in-situ precipitation method and subsequently analyzed through SEM, XRD, and XPS techniques. Notably, the bandgap structure of the heterojunctions was examined through UV-Vis DRS. The photocatalytic performance of the synthesized samples was assessed by studying the degradation of methyl orange. To further validate the photocatalytic process, EPR spectroscopy was employed to confirm the presence of radicals generated within the heterojunction. Results: The heterojunction displayed a characteristic type-II structure, enhancing light absorption and facilitating the separation of photoinduced carriers. Among the In2S3/CeO2 composites, the one with a 15 wt% CeO2 content exhibited the highest photocatalytic activity, achieving an 88% degradation of methyl orange after 90 min of exposure to visible light irradiation. Additionally, •O2 − is identified as the primary active species responsible for degradation. Conclusion: UV-Vis DRS illustrated the improved transfer and separation of photogenerated electrons attributed to the optimized band structure of the heterojunction. EPR spectroscopy yielded valuable information on active radicals, thereby proposing the photocatalytic degradation mechanism.

Immobilization of simulated An4+ in radioactive sludge via microwave sintering: Mechanistic and performance

In this study, we investigate radioactive sludge containing An4+ ions via simulation. Ce4+ is employed as a surrogate isotope for An4+ ions, and silicate glass particles are incorporated as stabilizing agents. Continuous microwave sintering technology is adopted to sinter the simulated radioactive sludge with varying CeO2 contents co-doped with 60 wt.% glass particles at temperatures of 1100 °C, 1200 °C, and 1300 °C to achieve sample vitrification. The phase evolution, microstructure, morphology, chemical stability, sample density, and porosity of the sintered specimens are analyzed comprehensively. The results indicate distinct maximum solubility limits at different sintering temperatures: 5 wt.%, 6 wt.%, and 13 wt.% for 1100 °C, 1200 °C, and 1300 °C respectively. Under these conditions, Ce is immobilized within the glass network structure. Notably, the Ce3+/Ce4+ ratio in the 1300 °C-Ce10 specimen reaches 2.04, and the combined percentage of Q3 and Q4 glass structural units exceeds 50 %. Beyond the optimal solubility limit, tetragonal CeO2 crystals are formed on the glass sample surface. The normalized leaching rate of Ce from the samples remains at 5.0 × 10−6 g m−2 d−1. Additionally, the sintered samples indicate densities ranging from 2.65 to 3.01 g/cm3 and porosities from 0.18 % to 1.8 %. This study introduces a novel perspective for addressing radioactive sludge treatment.

Experiments and mechanism of kinetics/stability of CO2 capture by Ce/Zr carrier-loaded MgO-based adsorbents

Magnesium oxide (MgO) has demonstrated tremendous potential in carbon capture and utilization (CCU) technology. However, it still faces limitations such as low adsorption kinetics and poor stability. In this study, the sol–gel combustion method was employed to synthesize MgO/molten salt composite adsorbents supported on Ce/Zr carriers. The investigation focused on the influence of carrier composition on adsorption performance. The experimental results revealed that as the loading of CeO2 increased, the adsorbent materials transitioned from a porous foam-like connectivity to the formation of a shell structure. Interestingly, the low content of CeO2 facilitated enhanced CO2 diffusion and hindered the aggregation of MgO aggregates, resulting in improved adsorption performance. Furthermore, the adsorbents supported on ZrO2 demonstrated excellent particle size stability and cyclic stability due to the higher Tamman temperature of ZrO2 and the uniform dispersion of MgO on ZrO2. Utilizing density functional theory, a surface configuration of CeO2/ZrO2 catalyst-modified MgO (100) was constructed to elucidate the enhanced adsorption mechanism of CeO2/ZrO2 on MgO. The cluster model revealed a strong interaction between cluster O atoms and CO2 molecules, enhancing the charge transfer capability of the MgO surface towards CO2 and consequently strengthening its adsorption performance.

Electron Structure Tuned Oxygen Vacancy-Rich AuPd/CeO2 for Enhancing 5-Hydroxymethylfurfural Oxidation.

The design of high activity catalyst for the efficiently conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) gains great interest. The rationally tailoring of electronic structure directly affects the interaction between catalysts and organic substrates, especially molecular oxygen as the oxidant. This work, the bimetallic catalysts AuPd/CeO2 were prepared by the combining method of chemical reduction and photo-deposition, effectively concerting charge between Au and Pd and forming the electron-rich state of Au. The increasing of oxygen vacancy concentration of CeO2 by acidic treatment can facilitate the adsorption of HMF for catalysts and enhance the yield of FDCA (99.0 %). Moreover, a series of experiment results combining with density functional theory calculation illustrated that the oxidation performance of catalyst in HMF conversion was strongly related to the electronic state of interfacial Au-Pd-CeO2. Furthermore, the electron-rich state sites strengthen the adsorption and activation of molecular oxygen, greatly promoting the elimination of β-hydride for the selective oxidation of 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) to FDCA, accompanied with an outgoing FDCA formation rate of 13.21 mmol ⋅ g-1 ⋅ min-1 at 80 °C. The perception exhibited in this research could be benefit to understanding the effects of electronic state for interfacial sites and designing excellent catalysts for the oxidation of HMF.

Physical and luminescence properties of Ce3+ activated strontium phosphate glasses

Strontium phosphate (SrO–P2O5–Al2O3–Gd2O3) glasses with 0.05, 0.1, 0.5, and 1 mol % CeO2 were prepared by the conventional melt quenching technique. These glasses' luminescence, scintillation, and physical properties were measured and discussed in detail. The density, refractive index, and oxygen packing density of the studied glasses were increased with an increase in CeO2 concentration. At lower concentrations of CeO2, the characteristic 310 nm emission from Gd3+ and broadband emission from Ce3+ ions were obtained under X-ray excitations. The intensity of both Gd3+ and Ce3+ emission bands under 270 nm Gd3+ excitations reduced with further increase in CeO2, showing the delayed energy transfer from Gd3+ to Ce3+ ions. The integrated X-ray-induced luminescence intensity of 0.5% CeO2 glass was found to be 21% that of reference BGO crystal. For the lower concentration of CeO2, a slow decay time along with the fast Ce3+ decay was observed and disappears for higher CeO2 concentrations. The fast luminescence decay in the range of 22 ns–30 ns was observed for all the PSAG:Ce glasses, which was attributed to the lifetime of the 4f-5d transition of the Ce3+ ions. The faster decay time and reasonable scintillation light suggest the application of these glasses for radiation detector applications.

Cerium Oxide Nanoparticle-Papain Enzyme Bioconjugate: Synthesis, Characterization and Optical Absorption Study for Biomedical Applications

Objective: Here, we synthesize cerium oxide nanoparticles, successfully characterize them, and study the interaction between enzymes and cerium oxide nanoparticles (CeO2 NPs) using a simple optical spectroscopic technique. Method: CeO2 was fabricated by chemical method. Characterizations were done using UV-Vis absorption spectra, FESEM images, and XRD data. For the biomolecular study, papain was used as a model enzyme. Two different concentrations of CeO2, namely a small concentration range (0.05810 to 0.40670 mM) and a large concentration range (0.58100 to 0.92961 mM), were taken to study the interaction with the papain. UV-Vis absorption spectra were recorded to study bioconjugate formation. Findings: The CeO2 NPs have an intense absorption peak at 352 nm and a band gap of 3.78 eV. The XRD pattern showed the unit cell is cubic with an average particle size of 41.36 nm. The binding of papain with CeO2 NPs resulted in a red shift in its absorption peak. The apparent association constant (Kapp) was calculated for the bioconjugate and found to be 0.747 × 103 M-1 for small concentrations and 0.278 × 103 M-1 for large concentrations. In large concentrations, aggregation occurs instead of corona formation. Novelty: To the best of our knowledge, this may be the first study of the interaction of papain enzyme with CeO2 NPs. This study contributes to the application of NPs in the field of biomedicine. Keywords: Cerium oxide, Papaya proteinase (PP), Absorption spectra, Bioconjugate, Association constant

Investigation of the Phase Composition, Structural, Mechanical, and Dielectric Properties of (1 − x)∙ZrO2-x∙CeO2 Ceramics Synthesized by the Solid-State Method

Ceramics based on zirconium dioxide are very important compounds for dental, implant, and structural material applications. Despite the fact that tetragonally stabilized YSZ has been well studied, the search for new compositions of zirconia-based ceramics is still in progress. The ZrO2-CeO2 system is one of the alternatives for YSZ materials, but there is conflicting experimental data on its phase composition and mechanical properties depending on the ratio of components. In this study, we investigated the phase composition, and microstructural, mechanical, and physical properties of (1 − x)∙ZrO2-x∙CeO2 (step of x = 0.05) ceramics obtained by the solid-state sintering process from micron-sized powders. For the characterization of samples, XRD, Raman spectroscopy, SEM, the Vickers Microhardness Test, and dielectric spectroscopy were implemented. The results showed that by varying the CeO2 concentration, it is possible to synthesize stable tetragonal ZrO2 at room temperature with a high microhardness HV0.05 value of ~1500, low porosity (~2.5%), and a high dielectric constant of 36. The pronounced combined effect of tetragonal phase formation, densification, and grain size reduction on the mechanical and dielectric properties of the experimental samples was investigated. Refined experimental data make it possible to synthesize high-quality zirconia–ceria ceramics for use as refractories, dispersed nuclear fuel, or solid oxide fuel cells.

Greatly improved energy storage density of SrO2–BaO2–Nb2O5–SiO2–Al2O3–B2O3 glass ceramics by various amount CeO2 doping

Glass ceramic dielectric materials with high power density and high energy density have important application value in the miniaturization and integration of lightweight pulse power devices. In this work, SrO2–BaO2–Nb2O5–SiO2–Al2O3–B2O3 glass ceramics doped with various contents of CeO2 were prepared via high-temperature melting combined with temperature-controlled crystallization process. Results showed that CeO2 doping increased the content of Ba0.27Sr0.75Nb2O5.78 tungsten bronze phase precipitate from the glass matrix in glass ceramics (from 55.7% to 82.2%), thereby increasing dielectric constant of SrO2–BaO2–Nb2O5–SiO2–Al2O3–B2O3 glass ceramics (from 66.5 to 101.9). Besides that, CeO2-doped ceramics exhibited excellent temperature stability and low loss (below 0.015). The highest breakdown strength (1590 kV/cm) and energy density (12.88 J/cm3) were achieved in the ceramic with a CeO2 doping concentration of 3.0 mol.%, being 3.03 times higher than those in undoped glass ceramic. The increase in energy density of the ceramics was attributed to moderate CeO2 doping concentration that improved the crystallinity (from 83.8% to 89.8%) and reduced the interfacial activation energy of the glass ceramics.

Effect of loading method on catalytic performance of Pt/CeO2 system for CO oxidation

The oxygen vacancies of CeO2 play a pivotal role in effectively dispersing and stabilizing noble metal nanoparticles (NPs). During the NPs loading process, the post-treatment condition, e.g. atmosphere, has a certain influence on the oxygen vacancy concentration of CeO2, highlighting the importance of suitable choice of loading technique. Herein, A-Pt/HCeO2 and I-Pt/HCeO2 catalysts are prepared by loading Pt NPs on HCeO2 with abundant oxygen vacancies (obtained from the calcination of a Ce(OH)CO3 precursor under H2) using ALD deposition and impregnation methods, respectively. Through detailed characterization and in situ DRIFTS analysis, it was noted that compared to the I-Pt/HCeO2 catalyst, the A-Pt/HCeO2 catalyst processes a uniform distribution of Pt NPs, more Pt0 active sites and oxygen vacancies, thus exhibiting an outstanding catalytic performance for CO oxidation. The ALD deposition technique mitigates the effects of high-temperature sintering and atmospheric exposure during the loading process of noble metal NPs, offering a more accurate assessment of the catalytic performance of catalysts.

EFFECT OF CeO2 NANOPARTICLES ON THE STRUCTURAL AND OPTICAL PROPERTIES OF (SnO2:Pd) FILMS PREPARED BY PLD TECHNIQUE

In this paper, pure and doped (SnO2:Pd ) films with CeO2 nanoparticles prepared by PLD technique using a highly intense Nd:YAG laser beam at 600 mJ with a frequency of second radiation at 1064 nm (pulse width 9 ns) repeating frequency (6 Hz) for 400 laser pulses incident on the intended surface has been performed. The stabilized (SnO2:Pd) doped with cerium oxide were used for deposition of the thin films on glass with thickness 200nm±05. Films of SnO2:pd were prepared with different doping concentrations of CeO2(0, 0.05, 0.10,0.15,0.20 and 0.25) wt. The FTIR and UV-Visible spectrophotometer were employed to investigate the structural, and optical characteristics of the films, respectively. FTIR spectra of (SnO2:Pd)1-xCeO2x thin films show seven peaks were assigned at wavenumber range from 2869.73 cm-1 belong to stretching bond CH2 to 492.98 cm-1 belong to N-O which can be indicated by the vibrations mode .The optical results show that transmittance decreased drastically by increasing the doping ratio. In contrast with absorbance, it increased by increasing of the doping ratio of cerium oxide. The optical energy gap was found to change systematic sequence with increasing of CeO2 concentration. Also the optical constant with different CeO2 contents were determined..

Ferroelectricity in Ce0.2-HfO2 films around 500 nm in thickness

CeO2-HfO2 solid solution thin films (Hf1-xCexO2) were deposited on Pt(111)/TiO2/SiO2/Si(100) substrates using the chemical solution deposition method. This study investigates the influence of CeO2 content and annealing temperature on the structure and ferroelectric properties of Hf1-xCexO2 films. Ferroelectric behavior is demonstrated in polycrystalline Hf0.80Ce0.20O2 films with thicknesses ranging from 163 to 524 nm. And the structure of the films is analyzed using glancing incidence X-ray diffraction. The comprehensive results indicate that Hf0.80Ce0.20O2 films annealed at 850 °C exhibit excellent ferroelectricity. Square hysteresis loops associated with the ferroelectric orthorhombic phase are observed, even in the 524-nm-thick film. The remnant polarization (Pr) and coercive field (Ec) range from 16 to 18 μC/cm2 and 1100–1250 kV/cm, respectively, under a maximum applied electric field of 2 MV/cm for all Hf0.80Ce0.20O2 films. Furthermore, the film presents thickness-insensitive characteristic. The current work paves the new way to design high-performance thick HfO2-based ferroelectric films.

Highly efficient asymmetric supercapacitor based on magnetic CeO2@γ-Fe2O3 composite and reduced graphene oxide electrodes

The CeO2@γ-Fe2O3 nanocomposites with varying CeO2 content (0–50 mol%) were prepared by the sol-gel electrospinning. XRD analysis confirmed the phase transition from α-Fe2O3 to cubic γ-Fe2O3 with addition of Ce ions and dominant phase for 30, and 50% CeO2@γ-Fe2O3 nanocomposites was cubic CeO2. FESEM images revealed that the ribbon-like α-Fe2O3 convert to the CeO2@γ-Fe2O3 nanofibers. The EDS map images and FTIR confirmed the homogenous distribution of elements and chemical bonds, respectively. Interestingly, the induced phase transition resulted in superparamagnetic behavior of 10% CeO2@γ-Fe2O3. The supercapacitive performance of the CeO2@γ-Fe2O3 nanofibers grown on the nickel foam were examined by electrochemical analyzes. The 50% CeO2@γ-Fe2O3 electrode demonstrated the highest specific capacitance of 1169.3 F g−1 at a current density of 1 A g−1 and the capacitance retention of 89.7% after 1000 cycles at 7 A g−1. Additionally, asymmetric supercapacitor (ASC) was assembled using CeO2@γ-Fe2O3 and rGO as cathode and anode electrodes, respectively. The CeO2@γ-Fe2O3//rGO ASC displayed an energy density of 36.8 Wh kg−1 at a power density of 700 W kg−1, demonstrating its potential for use in energy storage systems.

Photocatalytic treatment under visible light applied to aqueous glyphosate solution

Numerous chemical residues produced by industries and agricultural activities harm the environment. Pesticides and herbicides pollute soil and water and have toxic effects on living beings. Glyphosate – N-(phosphonomethyl)glycine – is an herbicide extensively used for the non-selective control of weeds. This systemic and post-emergent organophosphorus compound accounts for 60% of the world market of non-selective herbicides. Photocatalysis is one of the safest and least expensive methods for removing pesticides from wastewater. Evidence in the literature shows that photocatalysis has the potential for the removal of herbicides from surface waters and soil. The present study aimed to investigate the photocatalytic degradation and reduction of phytotoxicity of glyphosate in the presence of cerium dioxide (CeO2), titanium dioxide (TiO2) and zinc oxide (ZnO) as catalysts (2 g L-1) under a visible radiation source. Among the catalysts, CeO2 had the best efficiency, achieving 17% degradation, followed by ZnO (6.8%) and TiO2 (6.4%). The concentration of CeO2 was diminished to 1 g L-1 to assess its influence, leading to a reduction in degradation from 17% to 15%. Phytotoxicity of the product of the reactions was also evaluated and revealed a nonphytotoxic compound was formed in the photocatalytic reaction solution using CeO2 as the catalyst.

Effect of cerium dioxide on the anode performance of aluminum-air batteries

In this word, the effects of adding different contents of CeO2 to pure Al anode alloy plates on the anode performance of aluminum air batteries were evaluated using an electrochemical workstation, a blue dot test system, and scanning electron microscopy (SEM). The results showed that the addition of CeO2 had a positive effect on the discharge performance of aluminum anodes for aluminum-air batteries, especially at high current density of 100 mA·cm−2 for Al-0.20 wt% CeO2 and Al-0.25 wt% CeO2 anodes, and also improved the electrochemical activity, corrosion resistance, and anode utilization of aluminum anodes.