铜修饰微弧氧化二氧化钛网电极三维光电催化研究

实验采用微弧氧化技术制备了负载Cu2+的二氧化钛/钛(TiO2/Ti)网电极,考察了微弧氧化电解液浓度、光电催化电解质初始浓度、电解间距、外加电压对亚甲基蓝三维光电催化的脱色情况。结果表明,在6g/L的Na3PO4溶液中微弧氧化5min制备TiO2/Ti网电极的光催化效果最高达到25.3%;采用微弧氧化负载Cu2+法修饰TiO2/Ti网电极,当电解液中Cu2+的浓度为0.01mol/L,微弧氧化时间7min时制备的负载Cu2+的TiO2/Ti网电极,在三维光电催化体系为5mg/L的亚甲基蓝,0.01mol/L的硫酸钠溶液,1.5cm的电解间距,3.0V的外加电压以及pH为5的情况下,光电催化对亚甲基蓝的脱色率达到46.2%。     

高纯一氧化硅的制备与提纯

一氧化硅是半导体材料的原料,主要提纯手段,首先将二氧化硅制取好,纯度为(99.99)%高纯,然后将99%以上纯度的硅粉进行提纯处理,上述高纯的二氧化硅与硅粉配好混合料后,进行加热反应,然后灼烧,冷却后得成品。     

纳米氧化硅-氧化铝负载氧化物催化氧化甲醛

采用溶胶-凝胶法制备了纳米氧化硅-氧化铝材料,并利用浸渍法将氧化物负载在该纳米材料上。研究了室温环境下,纳米氧化硅-氧化铝材料负载氧化物去除甲醛的效果。结果表明了相比其他氧化物,负载MnO2的催化材料去除甲醛的效果最好;当负载量为3%左右时,效果最好。     

Si3N4粉末氧化生成SiO的研究

本文首次提出并采用NaOH H_2O_2的混合溶液作为SiO气体的吸收液,用硅钼兰分光光度法进行检测分析。结果表明,Si_3N_4粉末在高温下的低氧分压(Po_2≤10Pa)气氛中氧化时有SiO气体生成。其中当温度为1300℃时,在氧分压为1Pa～10Pa的N_2气氛中氧化时,生成SiO气体的氧化反应占Si_3N_4总的氧化反应的70～80％。同时,通过热力学计算对Si_3N_4粉末氧化生成SiO进行了分析,揭示了Si_3N_4的氧化反应方式与氧分压和温度的相互关系。     

锰改性氧化硅负载金催化剂用于醇气相选择性氧化的研究

为实现醇的高效气相选择性氧化,以四氧化三锰改性的氧化硅为载体制备了负载型金催化剂。实验结果表明,氧化硅经过四氧化三锰改性后,苯甲醇转化率和选择性明显提高。通过进一步调节四氧化三锰和金的负载量,可以实现醇的高效气相选择性氧化。当反应温度为250℃时,苯甲醇转化率和选择性可分别达到96%和98%。采用X射线粉末衍射(XRD)和透射电镜(TEM）等手段对催化剂进行了表征,结果表明,低负载量的四氧化三锰在氧化硅表面实现了单层分散,金颗粒粒径为12-14 nm,但是由于金和单层分散的四氧化三锰之间的相互作用,使得该催化剂体现出良好的醇气相选择性氧化催化性能。     

铜锡改性纳米二氧化钛光催化氧化还原性能的研究

在复合半导体基础上，采用超声浸渍法对催化剂表面作进一步铜改性，制备了铜锡改性的纳米二氧化钛光催化剂CuOx-SnO2／TiO2，考察了表面铜改性、二氧化锡复合对催化剂光催化氧化还原性能的影响．结果表明，表面铜改性和复合都有利于提高催化剂光催化氧化还原能力，二者间表现出相互增强的作用．结合XRD、XPS、TEM等催化剂表征结果，对铜锡改性纳米二氧化钛光激发机制进行了讨论，提出了二氧化碳光催化还原的可能机制．     

硅橡胶耐热老化性能的研究一铁铜氧化复合物的作用

研究了以铁铜氧化复合物为耐热添加剂的过氧化物高温硫化硅橡胶的热空气老化性能及其热稳定机理。通过热空气老化实验及热重法－差热分析表明：铁铜氧化复合物可以明显提高硅橡胶的热稳定性。     

铜常温发黑新工艺

１前言表面发黑技术广泛用于各种金属制品的表面防腐及装饰,传统的发黑工艺基本上使用硫化物或碳酸铜类,从使用情况看,存在着成本高、生产周期长、发黑液有臭味等缺点。从近年来的研究情况看,常温发黑液主盐成份大致可以分为硒铜系［１,２］、亚硒酸铜盐磷酸系...     

掺铜TiO^2光催化剂光催化氧化还原性能的研究

利用浸渍法制备了掺铜二氧化钛光催化剂，分别以乙酸降解和二氧化碳还原反应为探针，研究了催化剂的光催化氧化光催化还原性能．结果表明，铜掺杂能显著提高催化剂的光催化性能；结合光电子能谱、X光衍射分析等物理表征结果，对铜掺杂改性机制进行了讨论．     

棒状有序介孔锌掺杂氧化硅的合成与性能

采用共沉淀法经水热反应合成了棒状有序介孔锌掺杂氧化硅(mesoporous zinc-doped silica,MZS)材料,借助X射线衍射、Fourier变换红外光谱、光电子能谱、透射电镜、N2吸附-脱附、光致发光光谱等测试手段对有序介孔结构及光学性能进行了表征.结果表明:合成材料具有高度的长程有序结构,虽然锌的掺杂引起材料的比表面积的减小,但仍能保持介孔材料的有序性.合成材料中的Zn2 已经进入Si-O骨架并产生大量Si-O-Zn交联键,进而引发了MZS介孔材料的蓝色荧光发射强度显著增强且有明显蓝移.     

Oxidation Kinetics of Participate Silicon Monoxide

The air oxidation of particulate silicon monoxide to cristobalite was studied in the range 820° to 1040°C. This SiO neither disproportionates nor volatilizes in this range. An activation energy of 23.8 ± 2.0 kcal/mole for the diffusion of oxygen was obtained from a measure of the differential rate of reaction at various temperatures for various fixed percents of conversion up to 24%. The reciprocal time needed to reach a fixed percent of conversion up to 30%, at various temperatures, gave an activation energy of 24.2 ± 1.5 kcal/mole. It is concluded that the diffusional activation energy is 24.0 ± 2.0 kcal/mole.     

Oxidation of Carbon Monoxide Over SBA-15-Confined Copper,Palladium and Iridium Nanocatalysts

Abstract  

Copper, palladium and iridium nanoparticles were synthesised within the pore channels of selectively grafted mesoporous silica SBA-15. The support and catalysts were characterised by different techniques. The synthesized catalyst were able to catalyse oxidation of carbon monoxide with activity values as high as 7.0 × 10⁻³ mmol g⁻¹ cat s⁻¹ at 353 K. Carbon monoxide conversion was found to increase with decreasing nano particle size.     

Silicon Carbide Powder Synthesis from Silicon Monoxide and Methane

SiC was synthesized via the gas-phase reaction between SiO and CH₄ at 1500° and 1560°C in a tubular flow reactor. SiO vapor was generated from equimolar powder mixtures of Si and SiO₂ in the reactor while CH₄ was externally supplied. Products of different morphologies were collected at different longitudinal locations: whiskers, crystal aggregates, scale, and powder. The total yield of SiC, based on the amount of SiO generated, reached as high as 99%, of which 25–46% by mass was fine powder with sizes ranging from 60 to 300 nm.     

Kinetics of Silicon Monoxide Ammonolysis for Nanophase Silicon Nitride Synthesis

Silicon monoxide vapor generated from Si/SiO₂ mixed-powder compacts was used with NH₃ to synthesize silicon nitride in a tubular flow reactor operated at temperatures in the range of 1300°-1400°C. The ammonolysis of SiO with excess NH₃ was very rapid, yielding three different types of silicon nitride at different longitudinal locations in the reactor: amorphous nanophase powder of an average size of about 20 nm, amorphous whiskers of a few micrometers in diameter, and α-polycrystals. The amorphous products were heat-treated for crystallization at temperatures between 1300° and 1560°C in a stream of dissociated NH₃, N₂, or N₂/H₂ mixture gas. When dissociated NH₃ was used, nanophase powder was crystallized at 1300°C. The yield of nanophase silicon nitride from SiO varied from 13% to 43%, depending on operating conditions.     

In situ FTIR Study of Cobalt Oxides for the Oxidation of Carbon Monoxide

A high-valance cobalt oxide, CoO _x , was prepared from cobalt nitrate aqueous solution through precipitation with sodium hydroxide and oxidation by hydrogen peroxide. Further, other pure cobalt oxide species were refined from the CoO _x by temperature-programmed reduction (TPR) to 170, 230 and 300 °C. They were characterized by TPR and X-ray diffraction (XRD). Adsorption of CO and the co-adsorption of CO/O₂ over the cobalt oxides were further tested by in situ FTIR. It was shown that Co₃O₄ is quite active for the oxidation of CO at room temperature in the presence of oxygen, leading to the formation of CO₂. The variation in the oxidation of CO was interpreted with a mechanism involving two kinds of oxygen species, i.e., *-O₂ on the CoO _x surface and *-O_L on the surface of Co₃O₄ spinel structure.     

Disproportionation and Vaporization of Solid Silicon Monoxide

The vaporization rate of solid SiO was studied in the temperature range 1005° to 1475°C. It was concluded that ( a ) in an argon atmosphere the vaporization rate is external gas diffusion controlled; ( b ) only the upper layers of the charge contribute to the vaporization, so that a zero-order process is observed; ( c ) the heat of vaporization of SiO is 72.5 kcal/mole. Solid SiO disproportionates when heated in the temperature range 1000° to 1440°C, but the reaction does not go to completion. The reaction in the solid state is irreversible. The product silicon inhibits the reaction.     

Intrinsically Unstable Behavior during the Oxidation of Carbon Monoxide on Platinum

Abstract

Although the oxidation of carbon monoxide on platinum is one of the oldest known catalytic reactions and one of the most thoroughly studied, it continues to pose difficulties and challenges to both the experimentalist and the theoretician. For the most part, these are due to the frequent observations of hysteresis, associated with steady-state multiplicity, and self-sustained oscillations in the reaction and to the fact that no generally accepted theoretical explanation for them is at hand. even though a large number of studies have addressed the subject.     

Intrinsically Unstable Behavior during the Oxidation of Carbon Monoxide on Platinum

Although the oxidation of carbon monoxide on platinum is one of the oldest known catalytic reactions and one of the most thoroughly studied, it continues to pose difficulties and challenges to both the experimentalist and the theoretician. For the most part, these are due to the frequent observations of hysteresis, associated with steady-state multiplicity, and self-sustained oscillations in the reaction and to the fact that no generally accepted theoretical explanation for them is at hand. even though a large number of studies have addressed the subject.