Effective ethanol-to-CO_(2) electrocatalysis at iridium-bismuth oxide featuring the impressive negative shifting of the working potential

Since low overpotential for the anodic ethanol oxidation reaction(EOR)can favor the higher output voltage and power of direct ethanol fuel cells(DEFCs),it is critical to design new EOR catalysts with efficient ethanol-to-CO_(2)activity at low applied potentials.Thereby,carbon-supported Ir-Bi_(2)O_(3)(Ir-Bi_(2)O_(3)/C)catalysts with highly dispersive bismuth oxide on the iridium surface are designed and prepared,which can merit splitting the ethanol C–C bond and promoting the oxidation of C1 intermediates at the bifunctional interfaces.The as-obtained Ir-Bi2O3/C catalysts show superior EOR mass activity of up to ca.2250 m A mgIr-1.Moreover,they exhibit the record lowest onset oxidation potentials(0.17–0.22 V vs.RHE)and the peak potential(ca.0.58 V vs.RHE),being 130–300 m V lower than the previous landmark noble metallic catalysts.Furthermore,an apparent C1 pathway faraday efficiency(FEC1)of 28%±5.9%at 0.5 V vs.RHE can be obtained at Ir-Bi_(2)O_(3)/C.This work might provide new insights into the new anodic EOR catalysts for increasing the power of DEFCs.

Morphology and Electrochemical Properties of Activated and Sputtered Iridium Oxide Films for Functional Electrostimulation

Iridium oxide (IrOx) has attracted much attention for neural interface applications due to its ability to transfer between ionic and electronic current and to resist corrosion. The physical, mechanical, chemical, electrical and optical properties of thin films depend on the method and parameters used to deposit the films. In this report, the surface morphology, impedance and charge capacity of activated iridium oxide film (AIROF) and sputtered iridium oxide film (SIROF) were investigated in vitro and compared. The Utah Electrode Array (UEA) having similar electrode area and shape were employed in this study. The electrode coated with AIROF and SIROF were characterized by scanning electron microcopy, cyclic voltammetry, electrochemical impedance spectroscopy and potential transient measurements to measure charge injection capacity (CIC). SIROF and AIROF selectively deposited on electrode tip had dendrite and granular microstructure, respectively. The CIC of unbiased SIROF and AIROF was found to be 2 and 1 mC/cm2, respectively, which is comparable to other published values. The average impedance, at a frequency of 1 kHz was ~65 and ~7 kΩ for the AIROF and SIROF, respectively. Low impedance and high CIC makes SIROF highly recommended stimulation and recording material.

Iridium oxide fabrication and application: A review

Despite the scarcity and cost of iridium oxide,it is still the material of choice in numerous fields of science and applications,including capacitors,electrochromism,sensors,and various oxidation electrocatalysis(e.g.,chlorine evolution reaction,detoxification,and oxygen evolution reaction).Such versatility is attributed to the distinct features of iridium oxides,such as their activity,biocompatibility,conductivity,and durability.The features and properties of iridium oxides are strongly dependent on the fabrication method.In this review,methodologies relating to the synthesis and fabrication of solid-state iridium oxides have been thoroughly collected and discussed.Structuring and crystallization techniques for iridium oxides are also noted.At the end of the review,the effects of utilizing a certain fabrication method on the characteristics of the iridium oxide product are recapitulated,together with the recommended application of the product in various fields.

Self-assembling Synthesis of Vanadium Oxide Nanotubes and Simple Determination of the Content of V(IV)

High-yielding low-cost vanadium oxide nanotubes were prepared by the hydrothermal self-assembling process from vanadium pentoxide and organic molecules as structure-directing templates.Moreover,a new method was discovered for determining the content of V (IV) in vanadium oxide nanotubes by thermogravimetric analysis (TGA).This method is simple,precise and feasible and can be extended to determine the content of low oxidation state in the other transition metal oxide nanomaterials.

Energy-Exergy Analysis and Carbon (IV) Oxide Emission of an Aluminium Extrusion Plant in Nigeria

Energy security, cost of production and environmental constraints have necessitated the need for proper energy utilisation in the manufacturing industries. This work analysed energy and production data from an aluminium extrusion plant in Lagos, Nigeria for energy efficiency, exergy efficiency (or process?efficiency), energy cost per unit of production, CO2 emission and pollution?rate?index. The input-output energy analysis method was used to estimate the?embodied energy intensity. The pollution rate, energetic and exergetic efficiencies were estimated from the exergy analysis. The CO2 emission was estimated?from IPCC guideline on greenhouse inventories and the energy cost of unit?produce was estimated from energy cost accounting method. The five-year average thermal and electrical utilisation ratio was 45/55, which deviated from the 70:30 of the global best practices. The embodied energy intensity for the five years’ ranges between 2.31 - 162.3 GJ/t which is in excess of the recommended?range of (2.9 - 3.2 GJ/t). The mean energy efficiency for the five year was 79.4% and the mean exergetic efficiency was 57.8% indicating that production was well?managed (>50%) with energy wastages very high in boiler energy conversion. The total energy used was 16 MJ and CO2 emitted is 1.01 × 1011 g during the study period. The average pollution rate index for the plant was 0.8695 indicating that the plant is negatively impacting the environment due to technological limitation of the energy conversion process employed in the manufacturing plant. The study reveals a distortion of the recommended best practice in energy balance ratio which accounted for the high average cost of production (N 4418.3/t);process efficiency was generally low thereby negatively affecting industrial output for the company.

Stabilization of Nanoscale Tin（IV） Oxide on the Surface of Carbon Nanotubes

Surface of oxidized multiwalled carbon nanotubes was investigated for stabilization of nanosized tin（IV） oxide. The synthesis of nanosized tin（IV） oxide on the surface of carbon nanotubes was carried out with the use of three soft chemical methods： sol-gel, precipitation, and thermal. The synthesized tin（IV） oxide particles on the surface of carbon nanotubes were studied by thermal analysis, X-ray diffraction and electron microscopy. The lattice parameters of tin（IV） oxide on the surface of multiwalled carbon nanotubes were calculated.

A New Biosensor for Glucose Based on Screen Printed Carbon Electrodes Modified with Tin (IV)-Oxide

Tin (IV) oxide was used as a bulk mediator in carbon paste and carbon ink screen-printed electrodes to improve the better performance of the carbon electrodes for the detection of hydrogen peroxide in comparison with unmodified electrodes. A new glucose biosensor developed from modified carbon paste electrode and coated with glucose oxidase entrapped in Nafion was investigated with a flow injection system. The biosensor could be operated under physiological conditions (pH 7.5, 0.1 M phosphate buffer), with an operating potential of ?200 mV (vs. Ag/AgCl), a flow rate of the carrier of 0.2 mL/min. and an injection volume of 100 μL. The amperometric response of the biosensor showed good linearity up to 200 mg/L with a detection limit (3σ) of 6.8 mg/L. The relative standard deviation for the repeatability of measurements for 100 mg/L glucose was 2.9% (n = 10 measurements) and the corresponding reproducibility was 12% (n = 5 sensors). The effect of all investigated interferences (uric acid, paracetamol, xanthine, hypoxanthine and ascorbic acid) was not fatal and could be eliminated by the use of the standard addition method. The new biosensor was successfully applied to the determination of glucose in human blood plasma.

Hydrogen production via autothermal reforming of ethanol over noble metal catalysts supported on oxides

Hydrogen was produced over noble metal（Ir, Ru, Rh, Pd） catalysts supported on various oxides, including γ-Al2O3, CeO2, ZrO2 and La2O3, via the autothermal reforming reaction of ethanol （ATRE） and oxidative reforming reaction of ethanol （OSRE）. The conversion of ethanol and selectivites for hydrogen and byproducts such as methane, ethylene and acetaldehyde were studied. It was found that lanthana alone possessed considerable activity for the ATRE reaction, which could be used as a functional support for ATRE catalysts. It was demonstrated that Ir/La2O3 prevented the formation of methane, and Rh/La2O3 encumbered the production of ethylene and acetaldehyde. ATRE reaction was carried out over La2O3-supported catalysts （Ir/La2O3） with good stability on stream, high conversion, and excellent hydrogen selectivity approaching thermodynamic limit under autothermal condition. Typically, 3.4H2 molecules can be extracted from a pair of ethanol and water molecules over Ir（5wt%）/La2O3. The results presented in this paper indicate that Ir/La2O3 can be used as a promising catalyst for hydrogen production via ATRE reaction from renewable ethanol.

Kinetics and Mechanism of Iridium(Ⅲ)-Catalyzed Oxidation of Ethanol Amine by Cerium(Ⅳ) in Sulfuric Acid Media

In this study, the kinetics and mechanism of the iridium（ Ⅲ ） -catalyzed oxidation of ethanol amine（EAN） by cerium（Ⅳ） in a sulfuric acid medium was investigated using titrimetric technique of redox in a temperature range of 298--313 K. It was found that the reaction is of first order with respect to Ce（ Ⅳ ） and It（ Ⅲ ）, and a positive fractional order with respect to EAN. It was also found that the pseudo-first-order （ [EAN ] 〉〉 [ Ce （ Ⅳ） ] ） rate constant koba decreases with the increase of [ H^＋ ] and [ HSO^-4 ]. Under the protection of nitrogen gas, the reaction system can initiate the polymerization of acrylonitrile, indicating the generation of free radicals. On the basis of the experimental results, a suitable mechanism was proposed. From the dependence of koba on the concentration of hydrogen sulfate, Ce（SO4）2 was found to be the kinetically active species. The rate constants of the rote-determining step together with the activation parameters were evaluated.

Reduction Band Gap Energy of TiO₂Assembled with Graphene Oxide Nanosheets

This research work aims to reduce the band gap of thin layers of titanium oxide by the incorporation of graphene oxide sheets. Thin layers of the TiO2-GO composites were prepared on a glass substrate by the spin-coating technique from GO and an aqueous solution of TiO2. A significant decrease in optical band gap was observed at the TiO2-GO compound compared to that of pure TiO2. Samples as prepared were characterized using XRD, SEM and UV-visible spectra. XRD analysis revealed the amorphous nature of the deposited layers. Scanning electron microscope reveals the dispersion of graphene nanofiles among titanium oxide nanoparticles distributed at the surface with an almost uniform size distribution. The band gap has been calculated and is around 2 eV after incorporation of Graphene oxide. The chemical bond C-Ti between the titanium oxide and graphene sheets is at the origin of this reduction.

The Oxidative Decarboxylation of Nitrilotriacetic Acid (NTA)——A Study of the Reaction of NTA with Cerium(Ⅳ) in HCIO_4

The reaction between Ce (IV ) and NTA was investigated titrimetrically and spectrophotometrically. Two equivalents of Ce( IV ) are reduced per mole of NTA almost instantaneously at room temperature. With increasing reaction time an ultimate of about 7 equivalents of Ce( IV) is consumed per mole of NTA at room temperature. Carbon dioxide, formaldehyde and dimethylamine are the major and readily detectable products of oxidation of NTA by Ce( IV ). The rates of the reaction in HClO4 were measured spectrophotometricaUy using the stopped flow technique. The effects of both acidity of the medium and added salts support and extend preliminary results.

Oxidative Rearrangement via Oxycerication with Ce(IV) Salt

A mild and reliable procedure for the preparation of alpha-arylpropanoic acids from arylpropanone by Ce(IV) salt oxidative rearrangement is discribed.

INTERACTION OF PLASMA－LIQUID IN AN OXYGEN GLOW DISCHARGE IV OXIDATION DESULFURIZATION OF THIOPHENE

The plasma oxidation desulfurization of thiophene in the liquid phase was studied. Under optimum conditions, the degree of desulfurization and selectivity of the solid sulfide formation can be achieved up to 79% and 47% respectively.

PVP/Clay/Vanadium Oxide Nanocomposites Development and Characterization for Potential Use as Controlled Drug Release Matrix in Diabetes’ Treatment

Research in drug release field, nowadays, focuses on more efficient systems for better release of the drug and wider timespan of action, granting several benefits to the patient’s organism and to the industry. The present work aims on developing a matrix of polymer nanocomposite based on Polyvinylpyrrolidone (PVP), bentonite clay and two different vanadium oxides, via spray drying technique. The goal is to achieve a long and steady release of metformin hydrochloride in future formulations with this drug. Since either the nanocomposites or metformin hydrochloride is highly hydrophilic, it is most suited for a future formulation of tablets. For now, the nanocomposites obtained were characterized through Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR). The SEM and XRD analysis portrayed a very amorphous and homogenized material. TGA and FTIR proved the insertion of the nanoparticles, thus granting to the new material a slightly higher thermal resistance. The NMR analysis, using T1H parameters, is key for determining the formulations would behave better for extending the resistance of the nanocomposite’s matrix with the drug in later dissolution of tablets.

Coupling of on-Line Pre-Column Oxidative Cleavage and Solid-Phase Enrichment with Liquid Chromatography Using an Eco-Friendly Analytical Procedure to Determine Low Levels of Methotrexate

A simple, sensitive and precise green high-performance liquid chromatographic method including on-line pre-column oxidation combined by column switching with a short Hypersil ODS analytical column (100 mm × 4.0 mm i.d.) for enrichment and separation was developed and validated to determine low levels of methotrexate (MTX). The method was based on oxidative cleavage of MTX into highly fluorescence products, 2,4-diaminopteridine-6-carboxaldehyde and the corresponding 2,4-diaminopteridine-6-carboxylic acid, during the flow of phosphate buffer (0.04 M, pH 3.4) containing the analyte through the packed reactor of cerium (IV) trihydroxyhydroperoxide (CTH) at a flow-rate of 0.2 mL/min and 40℃. The fluorescent products were enriched on the head of ODS analytical column for the final separation. The separation was performed at room temperature using an environmentally friendly mobile phase consisting of ethanol and phosphate buffer (0.04 M, pH 3.4) in the ratio of 10:90 (v/v). The eluent was monitored at emission and excitation wavelengths of 463 and 367 nm, respectively. The method was successfully applied, without any interference from the excipients, for the determination of drug in tablets and vials with a detection limit of 0.06 ng/mL from 500 ?L of sample MTX.

黄芪甲苷对慢性间歇性缺氧诱导的遗尿症大鼠TLR4-p38 MAPK通路的影响

目的 探讨黄芪甲苷对慢性间歇性缺氧诱导的遗尿症大鼠Toll样受体4(Toll-like receptor-4,TLR4)/p38丝裂原活化蛋白激酶(p38 mitogen-activated protein kinase, p38 MAPK)信号通路的影响。方法 将SD大鼠随机分为对照组、模型组、黄芪甲苷低剂量组、黄芪甲苷中剂量组、黄芪甲苷高剂量组、去氨加压素组、脂多糖组、黄芪甲苷高剂量+脂多糖(Lipopolysaccharide, LPS)组,每组12只。除对照组外,其他组均需采用慢性间歇性缺氧诱导的方法构建遗尿症大鼠模型,各组大鼠每天于进入动物舱前1 h进行给药处理,1次/d,持续4周。末次处理24 h后,检测各组大鼠24 h排尿量及膀胱漏尿点压(bladder leak point pressures, BLPP)值的变化;ELISA法检测大鼠血清中抗利尿激素(antidiuretic hormone, ADH)含量;HE染色检测大鼠膀胱组织病理变化;比色法检测大鼠膀胱组织中超氧化物歧化酶(superoxide dismutase, SOD)活性、丙二醛(malonic dialdehyde, MDA)含量;Western blot检测大鼠膀胱组织中P2X3、TLR4、p-p38蛋白表达。结果 与对照组比较,模型组大鼠膀胱组织病理损伤严重,24 h排尿量增多,BLPP值变小,ADH含量、SOD活性降低,MDA含量和P2X3、TLR4、p-p38蛋白表达升高(P<0.05);与模型组比较,黄芪甲苷低剂量组、黄芪甲苷中剂量组、黄芪甲苷高剂量组、去氨加压素组大鼠膀胱组织病理损伤减轻,24 h排尿量减少,BLPP值变大,ADH含量、SOD活性升高,MDA含量和P2X3、TLR4、p-p38蛋白表达降低,LPS组大鼠膀胱组织病理损伤加剧,24 h排尿量增多,BLPP值变小,ADH含量、SOD活性降低,MDA含量和P2X3、TLR4、p-p38蛋白表达升高(P<0.05);与黄芪甲苷高剂量组比较,黄芪甲苷高剂量+LPS组大鼠膀胱组织病理损伤严重,24 h排尿量增多,BLPP值变小,ADH含量、SOD活性降低,MDA含量和P2X3、TLR4、p-p38蛋白表达升高(P<0.05)。结论 黄芪甲苷可能通过抑制TLR4/p38MAPK信号通路改善慢性间歇性缺氧诱导的大鼠遗尿症。

塔中深层稠油减氧空气驱氧化特征及机理研究

针对塔中深层稠油油藏开展静态氧化实验,通过测试分析不同氧含量与不同氧化时间下产出油气组成,研究了油藏注减氧空气过程中原油与减氧空气的氧化特征、氧化途径与氧化机理。实验结果表明,原油的耗氧速率与减氧空气的氧含量呈正相关,与氧化时间呈负相关;二氧化碳的生成量随氧化时间与减氧空气氧含量的增加而增大;原油与减氧空气的反应会一定程度上使原油黏度增加,其黏度增加的幅度随减氧空气氧含量的升高和氧化时间的增长而增大;氧化后原油饱和烃与芳香烃的含量减少,胶质与沥青质的含量增加,且沥青质增加更为明显。原油在氧化后出现了C=O的伸缩振动峰,且振动峰随着减氧空气氧含量的增加而增强,说明原油在氧化过程中发生了加氧反应生成了醛类等物质,且氧化反应随着氧含量的升高而不断加深。

IrO_(2)@SF纳米粒子的合成及其抗肿瘤应用

缺氧肿瘤微环境通常会促进肿瘤增殖和导致肿瘤细胞对活性氧(ROS)治疗的抵抗.选择丝素蛋白(SF)为模板,通过模拟生物矿化作用在SF表面矿化一层氧化铱(IrO_(2)),得到丝素蛋白和氧化铱的纳米复合物IrO_(2)@SF(IOS).天然SF的加载赋予了IOS多重抗肿瘤活性.实验结果表明:IOS具有较高的光热转换效率、过氧化氢酶和过氧化物酶活性以及较好的声动力效果.IOS能够通过分解肿瘤微环境过表达的过氧化氢,从而逆转肿瘤微环境的缺氧状态.体外细胞实验表明:IOS实现了光热联合纳米酶催化动力学抗肿瘤与声动力联合纳米酶催化动力学抗肿瘤治疗,2种多模式结合的治疗方式均展现了优异的抗肿瘤效果.同时,由于SF这种天然蛋白的加载,IOS还具有较高的生物相容性.

黄芪甲苷调控Nrf2/HO-1信号通路对血管内皮细胞氧化损伤的影响

目的 基于细胞实验研究黄芪甲苷(astragalosideⅣ,AST-Ⅳ)调控核转录因子红系2相关因子2/血红素加氧酶-1(nuclear factor-erythroid 2-related factor 2/heme oxygenase-1,Nrf2/HO-1)信号通路对血管内皮氧化损伤的影响。方法 采用1-棕榈酰基-2-(5'-氧-戊酰基)-sn-甘油-3-磷酸胆碱[1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine,POVPC]刺激血管内皮细胞24 h建立血管内皮细胞氧化损伤模型,随机分为模型(Model)组(35μmol/L POVPC)、AST-Ⅳ低剂量(AST-L)组(35μmol/L POVPC+50μmol/L AST-Ⅳ)、AST-Ⅳ高剂量(AST-H)组(35μmol/L POVPC+100μmol/L AST-Ⅳ)及AST-Ⅳ高剂量+ML385(Nrf2抑制剂)(AST-H+ML385)组(35μmol/L POVPC+100μmol/L AST-Ⅳ+5μmol/L ML385),以正常未处理细胞作为对照(Control)组。免疫荧光鉴定大鼠胸主动脉内皮细胞(aortic vascular endothelium cell,AVEC),CCK-8检测AST-Ⅳ细胞增殖情况,Transwell小室检测AVEC迁移情况,Matrigel基质胶检测细胞血管形成功能,鬼笔环肽染色检测细胞骨架结构,DCFH-DA荧光探针检测细胞活性氧(reactive oxygen species,ROS)水平,试剂盒法检测细胞培养上清液中超氧化物歧化酶(superoxide dismutase,SOD)水平,RT-qPCR和Western blot检测Nrf2和HO-1的mRNA及蛋白表达情况。结果 免疫荧光鉴定所提取的细胞,可特异性表达血管性血友病因子(von willebrand factor,v WF),鉴定为AVEC。与Control组相比,Model组细胞活力、迁移能力和血管形成功能显著下降(P<0.01),细胞骨架破坏明显,细胞内ROS水平显著上升(P<0.01),细胞培养上清液中SOD含量显著减少(P<0.01),细胞中Nrf2和HO-1的m RNA及蛋白表达水平下调(P<0.01或P<0.05)。与Model组比较,AST-L组及AST-H组细胞活力、迁移能力和血管形成功能显著升高(P<0.01),细胞骨架破坏得到较好修复,细胞内ROS水平显著下降(P<0.01),细胞培养上清液中SOD含量显著增加(P<0.01),细胞中Nrf2和HO-1的mRNA及蛋白表达水平显著上调(P<0.01),且以AST-H组效果更为显著(P<0.01)。与AST-H组比较,ASTH+ML385组迁移能力和血管形成功能显著下降(P<0.01),细胞骨架破坏增加,细胞内ROS水平显著上升(P<0.01),细胞培养上清液中SOD含量显著减少(P<0.01),细胞中Nrf2和HO-1的mRNA及蛋白表达水平显著下调(P<0.01)。结论 AST对血管内皮氧化损伤具有保护作用,且有一定的剂量依赖性,其机制可能是通过激活Nrf2/HO-1信号通路发挥作用。

钛(IV)固溶氧化镁纳米粉体的制备与表征

采用液相共沉淀方法,以Mg（NO3）2.6H2O和Ti（OC4H9）4为起始原料,NH3.H2O为沉淀剂,PEG为分散剂,冰乙酸为修饰剂,制备了钛（IV）固溶氧化镁纳米粉体。利用XRD,XPS和TEM等分析手段对粉体的物相组成、结构和形貌等进行了表征。结果表明Ti4＋固溶到MgO的晶格中,物相只有立方晶系的方镁石结构MgO相组成,无其它相存在。所制得的粉体颗粒尺寸小（约40~50 nm）、粒度分布均匀,具有良好的分散性能。