Nano crystalline powders of NiCu ferrite and NiCuZn ferrite prepared from citrate gel method： Synthesis and cnaracterzation

Nano size nickel copper ferrite powders （NiCuFe204） and nickel copper zinc ferrite powders have been prepared by a citrate gel precursor method. The resulting powders were characterized by X-ray diffraction （XRD） and scanning electron microscope （SEM）. The results showed that nickel copper ferrites and nickel copper zinc ferrites were also in the nanosaele. The NiCu ferrite powders showed extensive XRD fine broadening and sizes of crystals were calculated （from the XRD line broadening） as 26 run-44 run over the temperature range is 200-800℃. The NiCuZn ferrite powders showed XRD line broadening and sizes of of crystals were calculated 46-65 nm over 200-800℃.

TiO_(2)/CuO Films Obtained by Citrate Precursor Method for Photocatalytic Application

In the present work, the hybrid catalyst films of TiO2/CuO containing up to 10% in mol of copper were deposited onto glass surface. Precursor solutions were obtained by citrate precursor method. Films were porous and the average particle size was 20 nm determined by FEG-SEM analysis. The photocatalytic activities of these films were studied using Rhodamine B as a target compound in a fixed bed reactor developed in our laboratory and UV lamp. It was observed that the addition of copper to TiO2 increased significantly its photocatalytic activity during the oxidation of Rhodamine B. The degradation exceeded 90% within 48 hours of irradiation compared to 38% when pure TiO2 was used. Moreover, there was a reduction in the particles band gap energy when compared to that of pure TiO2. These results indicate that the TiO2/CuO films are promising catalysts for the development of fixed bed reactors to be used to treat effluents containing azo dyes.

Low Temperature Preparation of Ceria Solid Solutions Doubly Doped with Rare-Earth and Alkali-Earth and Their Properties as Solid Oxide Fuel Cells

A series of solid electrolytes, (Ce 0.8 Ln 0.2 ) 1- x M x O 2-δ (Ln= La, Nd, Sm, Gd, M:Alkali earth), were prepared by amorphous citrate gel method. XRD patterns indicate that a pure fluorite phase is formed at 800 ℃. The electrical conductivity and the AC impedance spectra were measured. XPS spectra show that the oxygen vacancies increase owing to the MO doping, which results in the increase of the oxygen ionic transport number and conductivity. The performance of ceria based solid electrolyte is improved. The effects of rare earth and alkali earth ions on the electricity were discussed. The open circuit voltages and maximum power density of planar solid oxide fuel cell using (Ce 0.8 Sm 0.2 ) 1-0.05 Ca 0.05 O 2- δ as electrolyte are 0.86 V and 33 mW·cm -2 , respectively.

BRIEF ARTICLE New reduced volume preparation regimen in colon capsule endoscopy

AIM:To evaluate the effectiveness of our proposed bowel preparation method for colon capsule endoscopy.METHODS:A pilot,multicenter,randomized controlled trial compared our proposed "reduced volume method"(group A) with the "conventional volume method"(group B) preparation regimens.Group A did not drink polyethylene glycol electrolyte lavage solution(PEGELS) the day before the capsule procedure,while group B drank 2 L.During the procedure day,groups A and B drank 2 L and 1 L of PEG-ELS,respectively,and swallowed the colon capsule(PillCam COLON capsule).Two hours later the first booster of 100 g magnesium citrate mixed with 900 mL water was administered to both groups,and the second booster was administered six hours post capsule ingestion as long as the capsule had not been excreted by that time.Capsule videos were reviewed for grading of cleansing level,RESULTS:Sixty-four subjects were enrolled,with results from 60 analyzed.Groups A and B included 31 and 29 subjects,respectively.Twenty-nine(94%) subjects in group A and 25(86%) subjects in group B had adequate bowel preparation(ns).Twenty-two(71%) of the 31 subjects in group A excreted the capsule within its battery life compared to 16(55%) of the 29 subjects in group B(ns).Of the remaining 22 subjects whose capsules were not excreted within the battery life,all of the capsules reached the left side colon before they stopped functioning.A single adverse event was reported in one subject who had mild symptoms of nausea and vomiting one hour after starting to drink PEG-ELS,due to ingesting the PEG-ELS faster than recommended.CONCLUSION:Our proposed reduced volume bowel preparation method for colon capsule without PEG-ELS during the days before the procedure was as effective as the conventional volume method.

Preparation and Catalytic Performance of Potassium Titanate Used as Soot Oxidation Catalyst

To prepare potassium titanate catalyst, a novel citrate acid complex-combustion method using CH3COOK and Ti（OC4H9）4 as raw materials was developed. The crystalline phase and surface morphology of K2Ti205 were investigated by X-ray diffraction （XRD）, field emission scanning electron microscope （FE-SEM） and transmission electron microscope （TEM）. The impact of some factors, such as the type of contact between K2Ti205 and soot, the content of water vapor and SO2 in exhaust, and the repeated use on catalytic activity of K2Ti205 were studied by temperature programmed reaction （TPR）. A comparison between the new method and the reported ones on catalytic activity of potassium titanate was investigated. The results showed that K2Ti205 had high catalytic activity and good stability.

Novel Mn-Ce bi-oxides loaded on 3D monolithic nickel foam for low-temperature NH_(3)-SCR de-NO_(x):Preparation optimization and reaction mechanism

This study explored the superior citrate method(CM)to synthesize Mn-Ce bi-oxides on 3 D monolithic Ni-foam(NF)catalysts for the selective catalytic reduction of NO by NH_(3)(NH_(3)-SCR).The 17 wt%Mn(7)Ce(3)O_(x)/NF(CM-17)catalyst shows the NO_(x)conversion of 98.7%at 175℃and 90%in the presence of 10 vol%H2 O.It is revealed that the combination of surface-active oxygen(formed by high-level oxygen vacancies)and strongly oxidized Mn4+species promots the Fast-SCR reactions,in which Mn4+species play a leading role in NH_(3)-SCR reaction,and the unsaturated Ni atoms and also Ce3+species promote electron exchange and thus improve the redox performance.The coexistence mechanisms of Fast-SCR reactions and E-R pathways are observed over Mn-CeO_(x)/NF catalyst,which may be promoted by the Br?nsted sites at low temperature.In addition,the heat resistance,stability,3 D monolithic porous structure and excellent physical properties of foam nickel provide a unique growth substrates for catalysts preparation and reaction sites for NO_(x)purification.Therefore,industrial application of Mn-Ce bioxides loaded on 3 D monolithic is proposed to be achieved through reasonable preparation methods.

Preparation of Sr_2Fe_(1-x)Sc_xMoO_(6-δ) nanopowders and its electrical conductivity

Double-perovskite Sr2Fe1-xScxMoO6-δ （x=0, 0.05, 0.1, 0.2, 0.3, 0.4） powders applied to the cathode of solid oxide electrolysis cells were synthesized by the sol-gel citrate combustion method. Initial powders were calcined at different temperatures under different atmosphere （air, H2（4 vol.%）/Ar）, and the effects of the preparation process on the structure and the morphology of the powders were investigated by thermal analysis （TG/DSC）, X-ray diffraction （XRD）, scanning electron microscopy （SEM） and surface area analysis. The electric conductiv-ity of the materials was measured by electrochemical work station using wafers prepared by dry pressing. It was found that the formation of perovskite structure was related to the content of Sc and combustion improver （NH4NO3）, pH value, calcining temperature and atmosphere. A single perovskite phase of Sr2Fe1-xScxMoO6-δ could be formed after 3 h calcining in reducing atmosphere of H2 （4 vol.%）/Ar at 1100 oC. The electrical property indicated that, this material had a potential to be used in medium/high temperature solid oxide fuel cells or electrolysis cells.

Preparation and reaction mechanism of novel Ce_(x)Co_(y)Cuz oxide composite catalysts towards oxidation of o-xylene

Ce_(x)Co_(y)Cuzoxide composite catalysts were prepared by using polyethylene glycol, citrate sol-gel method combined with PMMA template for the oxidation of o-xylene. The catalysts were characterized by the Xray diffraction(XRD), H2-temperature programmed reduction(H2-TPR), X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FT-IR), etc. The catalytic activity for o-xylene was investigated. The catalytic degradation pathway and mechanism of o-xylene were inferred. The results show that Ce O_(2)is mainly present on the surface of all catalysts. The surface area of Ce_(2)Co1Cu1is up to 77.2 m^(2)/g, and the average pore size is 10.62 nm. It exhibits redox and sufficient Ce^(4+)and Ce^(^(3+)), and reactive oxygen species, and has maximum O-H and C=O in the five catalyst samples. The catalytic activity of Ce2Co1Cu1is the best at low temperature, with the T50and T90values of 235 and 258°C at a space velocity of 32000 h-1, respectively. The o-xylene is oxidized to o-methyl benzaldehyde, and then further oxidized to o-methylbenzoic acid, and finally CO_(2)and H2O are formed.