表面离化微热板的结构设计和优化

对微热板温度、应力的分布以及功耗等情况的了解有利于微热板的优化设计,从而设计出性能符合要求的表面离化微热板．为此,用有限元方法对膜片型及梁支型微热板的温度和应力分布以及形变进行了模拟分析．结果表明:梁支型微热板不仅温度分布均匀,而且机械稳定性好,但是功耗较大;通过加热面积和梁长等结构尺寸的优化,可以有效降低功耗,同时能满足表面离化源对离化面积的要求．因此,梁支型微热板比膜片型微热板更适用于表面离化．

表面离化函数Φ（0）的研究

用试验方法测定了不同衬底材料上各种薄膜的表面离化函数Φ（０），并与Φ（０）的计算值加以比较。在计算中引入了一个有效的电子背散射系数，代表了衬底，薄膜原子序数不同时对Φ（０）的综合效应。在此基础上，详细讨论了Φ（０）值与衬底、薄膜二者的电子背散射系数，以及薄膜质量厚度的关系。

表面离化源工作参数对离子迁移率谱的影响

根据表面离化过程中样品分子在离化材料表面直接离化的特点,设计了一种样品离化和离子注入一步完成的面-网结构表面离化源。以金属钼为离化材料,三乙胺为测试样品,研究了离化源温度、离子门开门脉冲宽度和高度对离子谱图的影响。结果表明,离子流信号强度随离化温度升高迅速增强但离化源寿命缩短,理想的离化温度约为400℃;增加开门脉冲宽度和高度有利于提高系统响应灵敏度,但会降低分辨率,合适的脉冲宽度和高度分别为100"s和500V。该离化源制作简单,性能稳定,工作寿命长,在优化的工作参数下三乙胺的检出限<0.04mg/m3。

傅里叶变换表面离化离子迁移率谱仪

表面离化离子迁移率谱仪是一种可用于痕量含氮有机污染物检测的装置,具有灵敏度高、响应快等特点。文中尝试将傅里叶变换技术应用于表面离化离子迁移率谱仪,以提高表面离化离子利用率,从而提高仪器的信噪比。以三乙胺检测为例,比较了线性扫频和步进扫频两种工作模式。结果表明,与传统单周期扫描法相比,傅里叶变换表面离化离子迁移率谱仪的信噪比提高约3～5倍;线性扫频模式有更短的检测周期和较高的信噪比;在相近信噪比条件下,线性扫频模式傅里叶变换离子迁移率谱仪的扫描周期仅是多周期扫描信号平均法用时的1/4,因而更适用于快速检测。

基于微热板表面离子化源的离子迁移率谱仪研究

根据表面离化机理和离子迁移率谱检测方式,设计和制备了一种基于表面离化源的离子迁移率谱仪(IMS)。表面离化源为采用微机电系统(MEMS)工艺加工的微热板阵列,除了作为离子产生器,还作为漂移管的一个离子栅,用以实现离子向漂移区的注入。测试了该IMS对三乙胺的响应特性并研究了离子注入时间对离子迁移率谱的影响。结果表明,基于微热板表面离化源的离子迁移率谱仪对三乙胺具有很好的动态响应特性,三乙胺浓度的平方根与离子峰面积具有较好的线性关系,检出限可达6×10-8(V/V)。此外,与传统的放射离化IMS相比,这种IMS还具有离子注入时间短和离子迁移率谱基电流为零等特点。

Calculating models on surface tension of RE_2O_3-Mg O-SiO_2(RE=La, Nd, Sm, Gd and Y) melts

A thermodynamic model was developed for determining the surface tension of RE2O3-MgO-SiO2(RE=La, Nd, Sm, Gd and Y) melts considering the ionic radii of the components and Butler's equation. The temperature and composition dependence of the surface tensions in molten RE2O3-MgO-SiO2 slag systems was reproduced by the present model using surface tensions and molar volumes of pure oxides, as well as the anionic and cationic radii of the melt components. The iso-surface tension lines of La2O3-MgO-SiO2 slag melt at 1873 K were calculated and the effects of slag composition on the surface tension were also investigated. The surface tensions of La2O3, Gd2O3, Nd2O3 and Y2O3 at 1873 K were evaluated as 686, 677, 664 and 541 m N/m, respectively. The surface tension of pure rare earth oxide melts linearly decreases with increasing cationic field strength, except for Y2O3 oxide, while Y2O3 has a much weaker surface tension. The evaluated results of the surface tension show good agreements with literature data, and the mean deviation of the present model is found to be 1.05% at 1873 K.

Surface plasmon resonance-induced visible-light photocatalytic performance of silver/silver molybdate composites

Novel silver/silver molybdate（Ag/Ag2MoO4） composites with surface plasmon resonance（SPR）-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence of sodium dodecyl sulfate（SDS） in this study.The as prepared silver/silver molybdate（Ag/Ag2MoO4） composites were systematically characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and ultraviolet-visible diffuse reflectance absorption spectroscopy（DRS） in order to investigate their crystal structure,morphology and optical property as well.The photocatalytic activities of the composites were subsequently evaluated by their ability to degrade rhodamine B（RhB） under visible-light irradiation.Varies of controlled experiments were then carefully operated to gain a deep insight into the assembling of Ag/Ag2MoO4composites.It was found that preparation conditions such as pH,reaction time,and the amount of surfactant played important roles in the formation of composites with octahedral microstructures.And the composite obtained at 160 ℃ using 0.5 g of sodium dodecyl sulfate exhibited the highest photocatalytic performance under visible-light irradiation.Capture experiments were also conducted to clarify the function of different active species generated on the surface of Ag/Ag2MoO4during the photocatalytic process,in which both holes and ·OH radicals were found to play crucial role in photocatalytic removal of RhB under visible light irradiation.A possible photocatalytic mechanism of Ag/Ag2MoO4 was finally proposed on the basis of all the results to explain the higher photocatalytic activity of the octahedral Ag/Ag2MoO4 composites.It was inferred that the photoinduced ＂hot＂ electrons can quickly transfer from the Ag NPs to the conduction band of Ag2MoO4 and react with oxygen and H2O to generate a large quality of active radicals such as ·OH and ·O2^- because of the SPR effects.Besides,this SPR effects of Ag nanoparticles deposited on the surface of Ag2MoO4 can not only dramatically amplify its light absorption,especially in the visible region,but also promote the separation of photoexcited electron-hole pairs and effectively decrease electron-hole recombination.

Recent developments in visible-light photocatalytic degradation of antibiotics

With the significant discharge of antibiotic wastewater into the aquatic and terrestrial ecosystems, antibiotic pollution has become a serious problem and presents a hazardous risk to the environment. To address such issues, various investigations on the removal of antibiotics have been undertaken. Photocatalysis has received tremendous attention owing to its great potential in removing antibiotics from aqueous solutions via a green, economic, and effective process. However, such a technology employing traditional photocatalysts suffers from major drawbacks such as light absorption being restricted to the UV spectrum only and fast charge recombination. To overcome these issues, considerable effort has been directed towards the development of advanced visible light-driven photocatalysts. This mini review summarises recent research progress in the state-of-the-art design and fabrication of photocatalysts with visible-light response for photocatalytic degradation of antibiotic wastewater. Such design strategies involve the doping of metal and non-metal into ultraviolet light-driven photocatalysts, development of new semiconductor photocatalysts, construction of heterojunction photocatalysts, and fabrication of surface plasmon resonance-enhanced photocatalytic systems. Additionally, some perspectives on the challenges and future developments in the area of photocatalytic degradation of antibiotics are provided.

Effect of cetyltrimethylammonium bromide on morphology and porous structure of mesoporous hydroxyapatite

The mesoporous hydroxyapatite （HA） was synthesized by hydrothermal method utilizing cationic surfactant cetyltrimethylammonium bromide （CTAB） as template. The crystalline phase, morphology and porous structure were characterized respectively by different detecting techniques. The results reveal that the particles are highly crystalline hydroxyapatite phase. The surfactant has little influence on the morphology of the crystals, but affects the porous structure obviously. The sample without CTAB has a low surface area not exceeding 33 m^2/g, and no distinct pores can be observed by TEM. While the samples obtained with the surfactant get better parameters. Numerous open-ended pores centered at 2-7 nm spread unequally on the surface of the hydroxyapatite nanorods. The N2 adsorption-desorption experiments show type IV isotherms with distinct hysteresis loops, illustrating the presence of mesoporous structure. When the mole ratio of CTAB to HA is 1：2, the sample has the largest surface area of 97.1 m^2/g and pore volume of 0.466 cm^3/g.

Synthesis,characterization and photocatalytic performance of rod-shaped Pt/PbWO_4 composite microcrystals

Rod-shaped PbW O4 microcrystals of length 1 μm were fabricated by a hydrothermal route and subsequent calcination. Pt nanoparticles（NPs） of different contents（0.5 wt%,1 wt% and 2 wt%） were subsequently deposited on the PbW O4 microcrystals,producing robust Pt/PbW O4 composite microcrystals. The PbW O4 microcrystals and Pt/PbW O4 photocatalysts were characterized by X-ray diffraction,N2 sorption measurements,scanning electron microscopy,transmission electron microscopy,and X-ray photoelectron,photoluminescence,Fourier-transform infrared,and ultraviolet-visible diffuse reflectance spectroscopies. The photocatalytic performances of the catalysts were evaluated by the consecutive photocatalytic degradation of acid orange II dye. The Pt/PbW O4 composite microcrystals exhibited high photocatalytic activity and stability. The deposition of Pt NPs produced surface plasmon resonance（SPR）,which induced a large visible light absorption. A Pt NP content of 1-2 wt% resulted in an ~2 times increase in photocatalytic activity,compared with the activity of Pt/PbW O4. The crystal structure and high crystallinity of PbW O4 resulted in its favorable photocatalytic property,and the SPR effect of the Pt NPs promoted visible light harvesting. The Pt NPs also enhanced the separation of photo-generated electrons and holes,which further promoted the photocatalytic reaction.

Enhanced visible-light photo-oxidation of nitric oxide using bismuth-coupled graphitic carbon nitride composite heterostructures

Pure bismuth（Bi） metal-modified graphitic carbon nitride（g-C3N4） composites（Bi-CN） with a pomegranate-like structure were prepared by an in situ method.The Bi-CN composites were used as photocatalysts for the oxidation of nitric oxide（NO） under visible-light irradiation.The inclusion of pure Bi metal in the g-C3N4 layers markedly improved the light absorption of the Bi-CN composites from the ultraviolet to the near-infrared region because of the typical surface plasmon resonance of Bi metal.The separation and transfer of photogenerated charge carriers were greatly accelerated by the presence of built-in Mott-Schottky effects at the interface between Bi metal and g-C3N4.As a result,the Bi-CN composite photocatalysts exhibited considerably enhanced efficiency in the photocatalytic removal of NO compared with that of Bi metal or g-C3N4 alone.The pomegranate-like structure of the Bi-CN composites and an explanation for their improved photocatalytic activity were proposed.This work not only provides a design for highly efficient g-C3N4-based photocatalysts through modification with Bi metal,but also offers new insights into the mechanistic understanding of g-C3N4-based photo catalysis.

SPR effect of bismuth enhanced visible photoreactivity of Bi_2WO_6 for NO abatement

Bi2WO6 is a typical visible-light-responsive semiconductor photocatalyst with a layered structure.However,the relatively large bandgap(2.6–2.8 eV)and quick recombination of photo-generated carriers result in its low quantum efficiency.In this paper,Bi-nanospheres-modified flower-like Bi2WO6 was successfully prepared by solvothermal treatment of Bi2WO6 powders in Bi(NO3)3 solution using ethylene glycol as reductant.The photoreactivity of this photocatalyst was evaluated by the oxidation of NO in a continuous-flow reactor under irradiation by a visible LED lamp(λ>400 nm).It was found that both Bi nanospheres and flower-like Bi2WO6 precursor exhibit very poor photocatalytic activity with NO removal rates of only 7.7%and 8.6%,respectively.The photoreactivity of Bi/Bi2WO6 was found to steadily increase from 12.3%to 53.1%with increase in the amount of Bi nanospheres from 0 to 10 wt%.However,with further increase in the loading amount of Bi nanospheres,the photoreactivity of Bi/Bi2WO6 hybridized photocatalyst begins to decrease,possibly due to the light filtering by the Bi nanospheres.The enhanced visible photoreactivity of Bi/Bi2WO6 towards NO abatement was attributed to surface plasmon resonance driven interfacial charge separation.The excellent stability of Bi/Bi2WO6 hybridized photocatalyst towards NO oxidation demonstrates its potential for applications such as air purification.

Effects of Au nanoparticle size and metal-support interaction on plasmon-induced photocatalytic water oxidation

Plasmonic photocatalysis with tunable light absorption has aroused significant attention in so-lar-to-chemical energy conversion.However,the energy conversion efficiency of plasmonic photo-catalysts is impeded by ineffective charge separation and the lack of highly active sites for redox reactions.In this work,the Au nanoparticle size and Au-TiO2 interaction of the Au/TiO2 plasmonic photocatalyst were adjusted simultaneously using a post-calcination treatment.The visi-ble-ight-induced water oxidation activity exhibited a volcano-like relationship with the calcination temperature;the treated photocatalyst at 600°C manifested the highest activity.Characterization with UV-visible spectra,XRD,SEM,and XPS revealed that the effect of the Au nanoparticle size and Au-TiO2 interaction were both responsible for the increase in plasmon-induced water oxidation activity.

A Bi/BiOI/(BiO)_2CO_3 heterostructure for enhanced photocatalytic NO removal under visible light

Narrow-band BiOI photocatalysts usually suffer from low photocatalysis efficiency under visible light exposure because of rapid charge recombination. In this work, to overcome this deficiency of photosensitive BiOI, oxygen vacancies, Bi particles, and Bi2O2CO3 were co-induced in BiOI via a facile in situ assembly method at room temperature using NaBH4 as the reducing agent. In the synthesized ternary Bi/BiOI/(BiO)2CO3, the oxygen vacancies, dual heterojunctions (i.e., Bi/BiOI and Bi- OI/(BiO)2CO3), and surface plasmon resonance effect of the Bi particles contributed to efficient electron-hole separation and an increase in charge carrier concentration, thus boosting the overall visible light photocatalysis efficiency. The as-prepared catalysts were applied for the removal of NO in concentrations of parts per billion from air in continuous air flow under visible light illumination. Bi/BiOI/(BiO)2CO3 exhibited a highly enhanced NO removal ratio of 50.7%, much higher than that of the pristine BiOI (1.2%). Density functional theory calculations and experimental results revealed that the Bi/BiOI/(BiO)2CO3 composites promoted the production of reactive oxygen species for photocatalytic NO oxidation. Thus, this work provides a new strategy to modify narrow-band semiconductors and explore other bismuth-containing heterostructured visible-light-driven photocatalysts.

Decorating non-noble metal plasmonic Al on a TiO2/Cu2O photoanode to boost performance in photoelectrochemical water splitting

Designing low-cost and high-performance photoelectrodes with improved light harvesting and charge separation rates is significant in photoelectrochemical water splitting.Here,a novel TiO2/Cu2O/Al/Al2O3 photoelectrode is manufactured by depositing plasmonic nanoparticles of the non-noble metal Al on the surface of a TiO2/Cu2O core/shell heterojunction for the first time.The Al nanoparticles,which exhibit a surface plasmon resonance(SPR)effect and are substantially less expensive than noble metals such as Au and Ag,generate hot electron-hole pairs and amplify the electromagnetic field at the interface under illumination.The as-prepared TiO2/Cu2O/Al/Al2O3 photoelectrodes have an extended absorption range and enhanced carrier separation and transfer.Their photocurrent density of 4.52 mA·cm^-2 at 1.23 V vs.RHE represents an 1.84-fold improvement over that of TiO2/Cu2O.Specifically,the ultrathin Al2O3 passivation layer spontaneously generated on the surface of Al in air could act as a protective layer to significantly increase its stability.In this work,the synergistic effect of the heterojunctions and the SPR effect of the non-noble metal Al significantly improve the photoelectrode performance,providing a novel concept for the design of electrodes with good properties and high practicability.

Surface assembly of cobalt species for simultaneous acceleration of interfacial charge separation and catalytic reactions on Cd_(0.9)Zn_(0.1)S photocatalyst

Although photocatalytic water splitting has excellent potential for converting solar energy into chemical energy,the challenging charge separation process and sluggish surface catalytic reactions significantly limit progress in solar energy conversion using semiconductor photocatalysts.Herein,we demonstrate a feasible strategy involving the surface assembly of cobalt oxide species(CoO_(x))on a visible-light-responsive Cd_(0.9)Zn_(0.1)S(CZS)photocatalyst to fabricate a hierarchical CZS@CoO_(x) heterostructure.The unique hierarchical structure effectively accelerates the directional transfer of photogenerated charges,reducing charge recombination through the smooth interfacial heterojunction between CZS and CoO_(x),as evidenced by photoluminescence(PL)spectroscopy and various electrochemical characterizations.The surface cobalt species on the CZS material also act as efficient cocatalysts for photocatalytic hydrogen production,with activity even higher than that of noble metals.The well-defined CZS@CoO_(x) heterostructure not only enhances the interfacial separation of photoinduced charges,but also improves surface catalytic reactions.This leads to superior photocatalytic performances,with an apparent quantum efficiency of 20%at 420 nm for visible-light-driven hydrogen generation,which is one of the highest quantum efficiencies measured among noble-metal-free photocatalysts.Our work presents a potential pathway for controlling complex charge separation and catalytic reaction processes in photocatalysis,guiding the practical development of artificial photocatalysts for successful transformation of solar to chemical energy.

Polyethoxylation and polypropoxylation reactions：Kinetics,mass transfer and industrial reactor design

Ethoxylation and propoxylation reactions are performed in the industry to produce mainly non-ionic surfactants and ethylene oxide(EO)–propylene oxide(PO) copolymers.Both the reactions occur in gas–liquid reactors by feeding gaseous EO,PO or both into the reactor containing a solution of an alkaline catalyst(KOH or Na OH).Non-ionic surfactants are produced by using liquid starters like fatty alcohols,fatty acids or alkyl-phenols,while when the scope is to prepare EO–PO copolymers the starter can be a mono-or multi-functional alcohol of low molecular weight.Both reactions are strongly exothermic,and EO and PO,in some conditions,can give place to runaway and also to explosive side reactions.Therefore,the choice of a suitable reactor is a key factor for operating in safe conditions.A correct reactor design requires:(i) the knowledge of the kinetic laws governing the rates of the occurring reactions;(ii) the role of mass and heat transfer in affecting the reaction rate;(iii) the solubility of EO and PO in the reacting mixture with the non-ideality of the reacting solutions considered;(iv) the density of the reacting mixture.All these aspects have been studied by our research group for different starters of industrial interest,and the data collected by using semibatch well stirred laboratory reactors have been employed for the simulation of industrial reactors,in particular Gas–Liquid Spray Tower Loop Reactors.

Adsorption of Sulfate and Fluoride in Relation to Some Surface Chemical Properties of Oxisols

In the present work, the adsorption of sulfate and fluoride by two oxisols was studied, and during the adsorption OH- released from soils were measured and the change in surface charge carried by one of the soils after the adsorption of fluoride was examined. The results show that the adsorption of sulfate by oxisols and the release of OH- from oxisols both increased with the increase of sulfate added at a constant pH, but decreased when pH became higher gradually. The adsorption and release both decreased markedly after removal of iron oxide. The ratio of OH- to SO42- for Fe-removed soils decreased to 15-34% of the original soils. These results suggest that iron oxide was the chief carrier of hydroxyl groups capable of ligand exchange with sulfate in oxisols.Compared with sulfate, however, the amount of fluoride adsorbed, OH- released during the adsorption of fluoride and the ratio of OH- to F- were much larger. The effect of iron oxide on the adsorption of fluoride by oxisols was smaller than that on the adsorption of sulfate. The ratios of OH- to F- for an oxisol from Brazil were 0.62 and 0.48 respectively before and after removal of free iron oxides. This implied that iron oxide only provided a small amount of exchangeable hydroxyl groups capable of ligand exchange with fluoride in oxisol. The research results indicate that among the factors inducing the changes in some properties of oxisols after adsorption of fluoride, the role became less important in the sequence of the release of OH-> the increase of negative charge > the decrease of positive charge.

Ionization behavior of deep level donors in passive film formed on surface of stainless steel in 5% salt solution

Deep level donor＇s ionization behavior of passive film formed on the surface of stainless steel was investigated by Mott-Schottky plots. It is indicated that transformation process of deep level donors＇ ionization behavior of passive film on surface of stainless steel can be divided into 4 stages with rising immersion time. At the initial immersion stage （10 min）, Fe（II） located in the octahedral sites of the unit cell is not ionized and the deep level does not appear in Mott-Schottky plots. At the second stage （9-38 h）, Fe（II） located in the octahedral sites starts to be ionized, which results in deep level donors＇ generation and density of deep level donors almost is constant with augmenting immersion time but the thickness of space charge layer is more and more thicker with rising immersion time. At the third stage （48 h-12 d）, density of deep level donors rises with increasing immersion time and the thickness of passive films space charge layer decreases. At last stage （above 23 d）, both the space charge layer＇s thickness and density of deep level donors are no longer changed with increasing immersion time. In the overall immersion stage, the shallow level donors＇ density is invariable all the time. The mechanism of deep level donor＇s ionization can be the generation of metal vacancies, which results in crystal lattice＇s aberration and the aberration energy urges the ionization of Fe（ II ） in octahedral sites.

Regulation of isobutane/1-butene adsorption behaviors on the acidic ionic liquids-functionalized MCM-22 zeolite

The adsorption ratio of isobutane/1-butene on the catalyst surface is one of the most important factors for the C4 alkylation process. Regulation of isobutane/1-butene adsorption ratio on the zeolite-supported acid catalyst is a big challenge for catalyst preparation. To regulate the isobutane/1-butene adsorption ratio, four types of ionic liquid （i.e., IL） with different alkyl chain lengths and different acid group numbers were synthesized and were subsequently immobilized onto the MCM-22 zeolite. The as-synthesized IL-immobilized MCM-22 （i.e., MCM-22-IL） was characterized by FT1R, TGA, BET, XPS and XRD, and their adsorption capacities and adsorption molar ratios of isobutane to l-butene （I/O） were investigated to correlate with surface features of MCM-22-IL Results showed that the immobilization of ILs led to a decrease of specific surface area and pore volume. But the surface density of acid groups was increased and the adsorption molar ratio of isobutane/1-butene （I/O） was significantly im- proved by the immobilization of ionic liquids. The adsorption molar ratio of I/O is substantially improved from 0.75 to above 0.9 at 300 kPa upon immobilizing ILs. Although the alkyl chain length oflLs was found to have little effect on the adsorption molar ratio of I/O, the increase of acid group numbers led to a dramatic decrease in the adsorption I/O ratio. The results illustrated that immobilizing ionic liquids is an effective way to modify the textural, chemical and morphological properties of MCM-22. Accordingly, the immobilization of ionic liquids provides a novel and a feasible way to regulate the adsorption I/O ratio on an adsorbent or a solid catalyst.