Improved Co-precipitation Method Research Articles

Nix/TiO2 catalysts for enhancing the selectivity of methylcyclohexane dehydrogenation

The dehydrogenation of methylcyclohexane (MCH) is a widely used hydrogen storage technology, but nowadays, precious metal catalysts such Pt are used for this reaction and non-precious metal catalysts suffer from low selectivity and instability problems. Two catalysts, Ni20/TiO2 and Ni20/Al2O3, were prepared through the improved co-precipitation method and their dehydrogenation performance of MCH was compared. It was found that the application of TiO2 carrier could significantly reduce the acidity of the catalysts, and the nickel particles could be stably dispersed on the carriers, which could effectively improve the selectivity of the target product (toluene). In addition, the influences of different Ni contents, reaction temperatures, and weight hourly space velocity (WHSV) on the performance of the catalysts were also evaluated, and the results showed that the catalyst with 17.16 % Ni content exhibited high activity with up to 86.48 % conversion of MCH and 96.51 % selectivity of toluene, under atmospheric pressure condition with the reaction temperature of 375 °C and WHSV of 1.9 h−1, while 96.03 % and only 42.64 %, respectively, for the Ni20/Al2O3 catalyst. In addition, the catalyst exhibited excellent anti-coking ability, indicating that it has a promising future for industrial applications.

Synthesis of a nanosized homogeneous Al2O3–CeO2–ZrO2 composite as an oxygen-storage material for highly improved thermal durability

Al2O3–CeO2–ZrO2 (ACZ) is widely used in automotive catalysts as an oxygen-storage material. However, ACZ prepared by conventional synthesis methods has poor compositional homogeneity, resulting in thermal degradation of the oxygen storage capacity (OSC) because of the sintering of CeO2–ZrO2 (CZ) crystals. In this study, a nanosized homogeneous ACZ composite is synthesized by an improved co-precipitation method that uses a high-shear agitation reactor and a polyamine dispersant. The sol obtained using the abovementioned method is a monodisperse colloid with an average particle size of 3.2 nm. A quantitative analysis of transmission electron microscopy images reveals that the distribution of Al2O3 and CZ after calcination at 500 °C is 1.6 times more homogeneous in the resulting ACZ than that in the ACZ powder obtained by conventional co-precipitation. Such excellent homogeneity of Al2O3 and CZ distribution results in smaller CZ crystals (11.2 nm) than the conventional one (14.6 nm) obtained after calcination at 1100 °C. The smaller CZ crystals have 1.3 times higher OSC than that of the conventional one. Therefore, the developed method yields homogeneous and thermally stable ACZ that can be used as an efficient automotive catalyst. Furthermore, this method would also be useful for synthesizing homogeneous nano-composites with various elemental combinations.

Preparation of a Novel NiAlO Composite Oxide Catalyst for the Dehydrogenation of Methylcyclohexane

A series of NiAlO composite oxide catalysts with high surface areas and high Ni dispersion were prepared through an improved co-precipitation method. The new preparation method effectively improved the specific surface area and pore volume of the catalyst, promoted the dispersion of nickel species, alleviated the agglomeration of the catalyst, and improved the stability of the catalyst by strengthening the interaction between Ni and Al. The typical catalyst Ni20Al had a specific surface area of 359 m2/g and a NiAl2O4 phase. In the dehydrogenation of methylcyclohexane over the Ni20Al catalyst, the conversion of methylcyclohexane could reach 77.4%, with toluene selectivity of 85.6%, and a hydrogen release rate of 63.94 mmol g−1 h−1, and did not show any significant inactivation during the stability test over 29 h under the reaction conditions of reaction temperature 450 °C and LHSV = 4 mL g−1 h−1. However, the conversion of methylcyclohexane with the IM-NiAl catalyst prepared through the traditional impregnation method was only 50.75%, with toluene selectivity of 70.5%, and with a hydrogen release rate of 35.84 mmol g−1 h−1, and the lifetime of the catalyst was only 15 h.

Enhanced solar photo-thermal conversion performance by Fe3O4 decorated MWCNTs ferrofluid

In this work, water based ferrofluid with Fe 3 O 4 nanoparticles (NPs) decorated multi-walled carbon nanotubes (MWCNTs) nanocomposite (NC) was investigated for solar photo-thermal energy conversion application. The NC was synthesized via the improved co-precipitation method. The thermal and optical properties of NC ferrofluid were also studied in the concentration range of 0.001–0.2 wt%. The results showed that Fe 3 O 4 NPs connect on the outer walls of the MWCNTs uniformly and the saturation magnetization was found to be 31.26 emu/g. The solar photo-thermal energy conversion performance of the MWCNT/Fe 3 O 4 ferrofluids decreases with the solar radiation time and improves with the concentration. Moreover, the extra magnetic field would further enhance the photo-thermal conversion performance due to absorbed heat is effectively transferred by the axially arranged MWCNTs with ultrahigh thermal conductivity. As a result, the solar photo-thermal conversion efficiency of ferrofluid is 58% at the concentration of 0.01 wt%, and it has 30% enhancement in comparison with the water. Another 6% enhancement would be obtained under the action of magnetic field. • Fe 3 O 4 decorated MWCNTs ferrofluid is prepared by improved co-precipitation method. • MWCNT/Fe 3 O 4 nanocomposite would improve optical and thermal properties of water. • Ferrofluid has optimal concentration for photo-thermal conversion. • Further enhancement in photo-thermal conversion performance under magnetic field.

Speciation analysis of both inorganic and organic 129I in seawater and its application in the study of the marine iodine cycle.

A complete protocol is presented for the speciation analysis of 129I for both inorganic and organic iodine in seawater using coprecipitation and solid-phase extraction (SPE) combined with accelerator mass spectrometry (AMS). By modifying the iodide separation process and adding a crossover removal step, the improved coprecipitation method significantly reduces the cross-contamination of iodide and iodate to less than 0.05% in the speciation analysis of inorganic 129I, with the separation efficiencies of about 95% and 93% for iodide and iodate, respectively. The SPE-DOI method for the dissolved organic 129I (DO129I) analysis was developed, whereby we report the first direct observation of DO129I/DO127I atom ratios in seawater in this paper. 129I species in seawater from Tokyo Bay were analysed. The 129I results demonstrated that our protocol for speciation analysis of 129I is reliable and provided new insights into understanding the iodine cycle.

Effect of sintering temperature on the electrochemical performance of Li-rich Mn-basfed cathode material Li1.2Mn0.54Ni0.13Co0.13O2 by co-precipitation method

The multi-void spherical structure of Li-rich Mn-based cathode materials was successfully prepared with an improved co-precipitation method using acetate as the system. By XRD, TEM, and SEM characterization and observation, the materials at the sintering temperature of 800℃ have a favorable crystal structure and lamellar structure, and it has more uniform primary particle and secondary particle morphology under SEM. The electrochemical results show that the initial discharge capacity of LMNCO-800 at 0.1C is 239.2 mAh/g. At high rates of 0.5C and 2C, it can provide capacities of 200.2 mAh/g and 145.0 mAh/g, and the capacity retention rates of 200 cycles are 85.11% and 88.21%, respectively. It can be seen more intuitively from the capacity decay and dQ/dV diagrams at 1C that the capacity decay trend of the material is more stable when the sintering temperature is 800℃, which is more helpful to stabilize the structure and delay the transformation of the layered structure to the spinel structure.

Selection of Sodium Salt Electrolyte Compatible with Na0.67Ni0.15Fe0.2Mn0.65O2 Cathode for Sodium‐Ion Batteries

The construction of an optimized electrolyte system compatible with layered transition metal (TM) oxides is of great importance to advanced sodium‐ion batteries (SIBs). Herein, a low‐cost iron‐containing manganese‐based layered cathode material of Na0.67Ni0.15Fe0.2Mn0.65O2 (N‐NFM) is prepared through an improved coprecipitation method. Then, the chemical properties of interfaces between the N‐NFM cathode and organic liquid electrolytes based on NaClO4 and NaPF6 are investigated, respectively. Results show that the cathode electrolyte interphase (CEI) film formed in the NaPF6‐based electrolyte is dense and uniform, which inhibits the dissolution of TM ions effectively and provides a low energy barrier for the transport of Na+. Apart from that the CEI film formed in the NaClO4‐based electrolyte contains more organic but less inorganic compounds, resulting in an increase in impedance. In addition, it is believed that the stability of the CEI film is susceptible to the perchlorate with strong oxidizing property. In this role, a small part of the CEI film falls from the cathode surface, accelerating the dissolution of TM ions and leading to the reactivation of electrolyte decomposition.

Synthesis of Na2Mn0.8Fe0.2Fe(CN)6 and its application as cathode material of sodium ion battery

The Prussian blue cathode material with a unique three-dimensional structure in sodium ion batteries had great potential. Na2MnFe(CN)6 and Na2Mn0.8Fe0.2Fe(CN)6 cathode materials were prepared by the improved co-precipitation method of chelating agent, and the electrochemistry of the half-cell was tested. The results showed that the first discharge capacity of the two materials can reached 152.4mAh/g and 119.5mAh/g respectively at 0.1C(1C=170mA/g). The capacity retention rate of Na2MnFe(CN)6 was only 43.2% after 100 cycles at 0.2C current density, but Na2Mn0.8Fe0.2Fe(CN)6 can reached 70%. The capacity retention of Na2Mn0.8Fe0.2Fe(CN)6 can still reached 69.8% after 100 cycles at 0.5C current density. The discharge specific capacity fluctuation of Na2Mn0.8Fe0.2Fe(CN)6 was smaller than that of Na2MnFe(CN)6.

Synthesis and characterization of pure and Cu doped CeO2 nanoparticles: photocatalytic and antibacterial activities evaluation

This article reports the effect of pure CeO2 and Cu (1%, 3% and 5 mol %) doped CeO2 Nanoparticles (NPs) have been prepared by very simple and improved co-precipitation method. Synthesized NPs has been subjected to several analytical methods, viz. XRD, TEM and UV-Vis spectral analysis. XRD data analysis confirmed that face cubic structure and average size are found to be in the range 5-10nm. Particle size and morphological studies as observed from TEM exhibits almost identical cubical shaped particles with average size 5-8nm. The tuning of band gap energy has been observed from UV-Visible absorption spectrum of cerium oxide NPs upon Cu (1%, 3%, and 5mol %) incorporation. Degradation of the methylene blue (MB) through photocatalysis has been observed for pure and Cu (1%, 3% and 5 mol%) CeO2 nanoparticles under solar spectrum. In addition, pure and Cu (1%, 3% and 5 mol %) cerium oxide nanoparticles has also been subjected to antibacterial response using different strains.

Spin reorientation transition in nanoscale multiferroic PrFeO3 and its band structure calculation

The synthesis of a nano-dimensional cluster of PrFeO3 orthoferrite with interesting tunable characteristics is the principal objective of this work. We document a very simple and improved co-precipitation method to synthesize nanoparticles of the desired dimension of rare earth substituted orthoferrite PrFeO3. The structural distortion is analyzed with Powder X-ray diffraction, which explores a distorted perovskite crystallized ferrite with space group Pbnm (62). The electrical behaviour of the prepared sample is investigated in a frequency range of 50 Hz to 5 MHz at different temperatures. A shift in the dielectric behaviour is noticed at about 250 °C. The morphological structure of the sample explored with High Resolution Transmission Electron Microscope (HRTEM), portraits a nano clustered structure. The magnetic properties of PrFeO3 are observed with Vibrating Sample Magnetometer (VSM) at 20 K and 300 K. A Very interesting change in magnetization is noticed at about 172 K–200 K. The effect of temperature on magnetic properties of PrFeO3 is reportedly due to the spin reorientation transition from Γ2 →Γ4 at TSR ≈ 172 K–200 K temperature range. The electronic band structure of nanoscale PrFeO3 with spin up and spin down states of antiferromagnetic nature is reported. PrFeO3 also exhibit multiferroic properties.

A new and improved synthesis method for the formation of ZnFe-CO3 and ZnFe-SO4 Hydrotalcites free from impurities

The synthesis of ZnFe-CO3 and ZnFe-SO4 Hydrotalcites (HTLCs) has been previously described in numerous literature reports but these methods contain impurity phases that arise from a lack of understanding of the experimental conditions under which these impurities form during the precipitation of these types of HTLCs. Furthermore, the majority of these reports in which impurities are present in addition to the ZnFe-CO3 and ZnFe-SO4 HTLCs have then been used for environmental and catalytic applications leading to the misinterpretation of their materials properties as a result of the fact that they contain non-HTLC phases. In our study, we have developed a new and improved co-precipitation method for the synthesis of ZnFe-CO3 and ZnFe-SO4 HTLCs free from impurities that are experimentally and rationally based on the use of a proper: (1) Iron source (Fe2+), (2) oxidant (30% H2O2) and (3) target pH (pH of 7) to avoid the commonly found impurities in the literature. The synthesized ZnFe-CO3 and ZnFe-SO4 HTLCs are then characterized via the use of ICP-OES, XRD, ATR-IR, Raman, SEM, TEM, BET and TGA to explore their chemical and physical properties. Our work here offers the research community a new and improved synthesis method for the preparation of ZnFe-CO3 and ZnFe-SO4 HTLCs free from impurities designed for applications in a variety of multidisciplinary research areas.

Fast Removal of Methylene Blue by Fe₃O₄ Magnetic Nanoparticles and Their Cycling Property.

The fast removal of dyes from aqueous solution and the recycling of adsorbents are currently popular topics in the study of adsorbents. Fe₃O₄ magnetic nanoparticles (MNPs) are usually applied in the preparation of composite adsorbents as magnetic carriers. Therefore, it is significant if single Fe₃O₄ MNPs can quickly remove dyes from aqueous solution with good cycling stability. Here, we report the preparation of Fe₃O₄ MNPs through an improved co-precipitation method, which has the inherent advantage of fast, inexpensive and without requiring the protection of nitrogen or an inert gas. The as-prepared Fe₃O₄ MNPs were used as an adsorbent to remove of methylene blue (MB) under alkaline condition, and then they were characterized by different measurements. The adsorption process was studied by various parameters, such as solution pH, initial MB concentration and contact time. The adsorption of MB over Fe₃O₄ MNPs reached equilibrium in 5 min, and it was observed to obey the pseudo-second-order kinetics model and Langmuir isotherm with a maximum adsorption capacity of 45.43 mg/g at pH = 12 and T = 298 K. Furthermore, two simple methods for desorption and chemical oxidation were used to the regenerate Fe₃O₄, and it turned out that Fe₃O₄ magnetic nanoparticles were able to maintain a high adsorption capacity (36 mg/g for desorption and 36.9 mg/g for chemical oxidation, respectively) after 4 circulations.

Effect of grinding method on the precursor powder of Bi2223 and properties of strip

In this paper, the two kinds of precursor powders of BiPb2212 and CaCuO2 were prepared by double powder method and an improved coprecipitation method, and then the BiPb2212 powders were fabricated by mechanical grinding and hand grinding. The BiPb2212 powders and CaCuO2 powders were prepared by two kinds of grinding methods mixed with a certain proportion of grinding, the Bi2223 superconducting tape with 37 filaments were prepared by removing the carbon, filling tube and annealing. The XRD analysis, SEM observation, laser particle size analysis and the tap density test of the precursor BiPb2212 powders were carried out respectively by mechanical grinding and hand-grinding. The results showed that the phase composition, microstructure, particle size distribution and tube density detection were all significant differences by using two kinds of grinding methods. Finally, the superconductivity test of the treated strip results show that the critical current from the field for the Bi2223 multi-core strip at 77K is improved from 86A (hand-grinding method) to 127A( mechanical grinding method). Therefore, the Bi2223 precursor powder by using mechanical grinding method is more conducive to obtain high-performance.

Facile synthesis and electrochemical properties of LiNi0.8Co0.15Al0.05O2 with enlarged exposed active planes for Li-ion batteries

Because enlarged exposed active planes facilitate the improvement of the rate capability of layered cathode material by providing more points for Li+ intercalation/de-intercalation, LiNi0.8Co0.15Al0.05O2 layered cathode material with enlarged exposed {010} active planes is desirable. In this article, micro-sized LiNi0.8Co0.15Al0.05O2 particles possessing enlarged exposed {010} active planes have been synthesized using Ni0.842Co0.158(OH)2 precursor prepared by an improved co-precipitation method. As-prepared LiNi0.8Co0.15Al0.05O2 demonstrates a good rate capability. The reversible capacity is 103 mAh g−1 at 10 °C, which is explained by the enhanced Li+ diffusion coefficient detected by CV and GITT measurements and reduced charge transfer resistance calculated by EIS tests. Moreover, the as-prepared LiNi0.8Co0.15Al0.05O2 also displays a good cycling stability. The capacity retention after 100 cycles at 0.2 °C is 85%. This good cycling stability can be ascribed to the porous structure of LiNi0.8Co0.15Al0.05O2 which provides a buffer area for volume expansion of the primary particles during cycling.

Magnetic Cr(VI) Ion Imprinted Polymer for the Fast Selective Adsorption of Cr(VI) from Aqueous Solution

In this study, a novel magnetic Cr(VI) ion imprinted polymer (Cr(VI)-MIIP) was successfully synthesized and used as a selective sorbent for the adsorption of Cr(VI) ions from aqueous solution. It can be synthesized through the combination of an imprinting polymer and magnetic nanoparticles. The high selectivity achieved using MIIP is due to the specific recognition cavities for Cr(VI) ions created in Cr(VI)-MIIP. Also, the magnetic properties that could be obtained using magnetic nanoparticles, helps to separate adsorbent with an external magnetic field without either additional centrifugation or filtration procedures. The magnetic Fe3O4 nanoparticles (MNPs) were synthesized using an improved co-precipitation method and modified with tetraethylorthosilicate (TEOS) before imprinting. The magnetic Cr(VI) ion imprinted polymer was prepared through precipitation copolymerization of 4-vinylpyridine as the complexing monomer, 2-hydroxyethyl methacrylate as a co-monomer, the Cr6+ anion as a template, and ethylene glycol dimethacrylate (EGDMA) as a cross-linker in the presence of modified magnetite nanoparticles. This novel synthesized sorbent was characterized using different techniques. Batch adsorption experiments were performed to evaluate the adsorption conditions, selectivity, and reusability. The results showed that the maximum adsorption capacity was 39.3 mg g−1, which was observed at pH 3 and at 25 °C. The equilibrium time was 20 min, and the amount of adsorbent which gave the maximum adsorption capacity was 1.7 g L−1. Isotherm studies showed that the adsorption equilibrium data were fitted well with the Langmuir adsorption isotherm model and the theoretical maximum adsorption capacity was 44.86 mg g−1. The selectivity studies indicated that the synthesized sorbent had a high single selectivity sorption for the Cr(VI) ions in the presence of competing ions. Thermodynamic studies revealed that the adsorption process was exothermic ( $$\Delta H$$ < 0) and spontaneous ( $$\Delta G$$ < 0). In addition, the spent MIIP can be regenerated up to five cycles without a significant decrease in adsorption capacity.

Calcium oxide functionalized with strontium as heterogeneous transesterification catalyst for biodiesel production

The application of calcium oxide (CaO) as transesterification catalyst for biodiesel production is restricted due to the requirement of long reaction time and high molar ratio of methanol to oil. To solve this problem, CaO was functionalized with strontium (Sr/Ca catalyst) through the solid mixing method, wet impregnation method, co-precipitation method and improved co-precipitation method, respectively. Stability of the prepared catalyst, including the homogeneous contribution of leached active sites and the catalyst reusability, was investigated to screen the optimal preparation method, and the improved co-precipitation method was proved to be the most ideal method for the strongest interaction between Sr and Ca. The Sr/Ca catalysts were then characterized by X-ray diffraction (XRD), thermogravimetric analysis–derivative thermogravimetric (TGA–DTG), Hammett indicator (basic strength and basicity) and Fourier transform infrared spectroscopy (FTIR). Moreover, effects of the activation temperature and Sr/Ca molar ratio on catalytic activity were concerned. At activation temperature of 900°C and Sr/Ca molar ratio of 0.5, the maximum conversion 98.31% of palm oil to fatty acid methyl esters could be achieved under the mild transesterification condition of 5wt.% catalyst amount (based on oil weight) and 9molar ratio of methanol to oil at 65°C for 30min.

Preparation, characterization, and phosphate removal and recovery of magnetic MnFe2O4 nano-particles as adsorbents

ABSTRACTPhosphate removal is an important method for controlling eutrophication in bodies of water. Adsorption is an effective phosphate removal approach. In this research, the adsorbent, namely, MnFe2O4, was prepared through the improved co-precipitation method and investigated in terms of phosphate removal. MnFe2O4 was characterized by scanning electron microscopy, vibrating sample magnetometry, X-ray diffraction, and Fourier transform infrared spectroscopy. Phosphate adsorption by MnFe2O4, desorption of adsorbed MnFe2O4 with the regeneration of desorbed MnFe2O4, and phosphate recovery were researched. Experimental results showed that adding the appropriate amount of polyethylene glycol to MnFe2O4 precursors during preparation inhibited the agglomeration of MnFe2O4 between particles because of the magnetic property of MnFe2O4 etc. High crystallinity and strong magnetism were achieved by MnFe2O4 at low temperatures. Average particle size was 5.1 nm. The hysteresis loops confirmed the ferrimagnetic behaviour of MnFe2O4 with a high saturation magnetization (i.e. 26.27 emu/g). The adsorption mechanism of phosphate was mainly physical. The prepared MnFe2O4 had a spinel structure. The proposed technique achieved a phosphate removal rate of 96.06%. A considerable amount of phosphate was desorbed from the adsorbed MnFe2O4 in 15 w/v% NaOH solution. The adsorption capacity of the desorbed MnFe2O4 could be restored to 96.73% in 10 w/v% NaNO3 solution through ion exchange. A sustainable phosphate source was recovered via hydroxyapatite crystallization in the desorption solution, which contained an abundant amount of phosphate as seed for suitable recovery condition. This finding suggested that MnFe2O4 could be a promising adsorbent for efficient phosphate removal.

Thermo-optical characterization of CdZnS nanoparticle colloids

Thermo-optical properties of cadmium zinc sulfide (CdZnS) nanoparticle colloids are investigated by interferometry technique. The nanoparticle colloids are synthesized by an improved co-precipitation method. Transmission electron microscopy, UV–vis spectrometry and X-ray diffraction analysis are used to characterize the CdZnS nanocrystals. The thermo-optic coefficient of the colloids has been determined using a Fizeau interferometer. For this purpose, the interference patterns are deformed by a photothermal phase shift which is locally induced in the sample by the focused pump laser beam. The change in the refractive index at this region imposes a shift on the phase of the fringe patterns. Fourier analysis performed on the interference patterns allows us to estimate the values of the thermo-optic coefficient and nonlinear refractive index of the sample. It is shown that the CdZnS nanoparticle colloids enhance the absorption of the laser light and induce high rise in the temperature of the sample, which leads to the nonlinear phase shift.

Preparation and bioassay explore of methotrexatum/zinc-aluminum layered double hydroxides

Methotrexatum/zinc-aluminum layered double hydroxides(MTX/Zn-Al-LDHs) compounds were prepared by the improved coprecipitation method in the alcohol-aqueous mixed solvent. The influence of molar ratios of Zn2+/Al3+/MTX(R value) on the structure and morphologies of the compounds was systematically studied. The MTX/LDHs compounds were characterized by X-ray diffraction(XRD), fourier transform infrared spectroscopy(FT-IR), transmission electron microscope(TEM), scanning electron microscope(SEM), atomic force microscope(AFM) and UV-visible diffuse spectroscopy(UV-Vis). The results indicate that the particles display curly sheet form with a little agglomeration, for the crystallite nucleation and growth along the a-b axes are more favorable than c axe, and the size of particles decreases with increasing the content of MTX. Then in vitro release behavior of the drugs from LDHs in pH 7.4 phosphate buffered saline(PBS) was observed, and two kinetics models(modified Freundlich model and parabolic diffusion model) were chosen to simulate the release kinetics of the drugs from LDHs. The release process involved two stages: firstly surface diffusion and secondly intraparticle diffusion. Moreover, the anticancer efficacy of both MTX and MTX/LDHs compounds were also estimated in vitro by the bioassay such as MTT assay with the human lung cancers(A549). According to the cell-line tests, LDHs itself does not exhibit obvious cytotoxicity within the studied concentration, and the anticancer efficacy tests for the MTX/LDHs compounds turn out to be more effective in cell suppression compared to the MTX itself, and the smaller the particle size is, the better anticancer efficacy could be.

Synthesis and Cathodoluminescent Properties of Y2O3: Eu3+ Phosphor with Micron-sized Controllable Particles

Abstract The luminescent properties of phosphors are sensitive to their morphologies, particularly to the sizes of phosphor particles. The optimal morphology of the phosphor for the field emission display (FED) is the microsized sphere-like particles. However, less attention has been paid to the phosphors with micron-size controlled particles. In this paper, we reported an improved co-precipitation method to synthesize the red-emitting Y 2 O 3 :Eu 3+ phosphor with the particle sizes controlled in several microns. The optimum phosphors were obtained at the calcination temperature of 1050 °C and pH=5.5, showing the sphere-like particles with the size distribution from 0.9 μm to 3.1 μm. Compared with the commercial phosphors, such optimum phosphors greatly enhance the cathodoluminescent properties and the corresponding luminescence intensity under the low excitation voltage of 1 kV is increased by 50%. Results indicate an effective way to develop the high-quality FED phosphors.