β-Bi2O3修饰Bi2WO6光催化降解苯酚及其可能机理

采用简单混合法制备了一系列Bi₂O₃/Bi₂WO₆复合光催化剂. 在紫外光降解水中苯酚的过程中, Bi₂O₃/Bi₂WO₆的光催化活性随Bi₂O₃含量的增加呈现先增大后减小的趋势. 当Bi₂O₃最佳负载量等于12.5% (质量分数, w)时, 该复合光催化剂的活性大约是单一Bi₂WO₆的4 倍. 固体样品表征表明, Bi₂O₃主要以β-Bi₂O₃存在, 复合光催化剂是Bi₂O₃和Bi₂WO₆的简单混合物. 此外, 在电催化氧化水的过程中, β-Bi₂O₃/Bi₂WO₆薄膜电极的光电流远大于β-Bi₂O₃和Bi₂WO₆薄膜电极的光电流之和. Bi₂O₃对Bi₂WO₆光催化的促进作用是由于前者接受后者的光生空穴, 提高Bi₂WO₆光生载流子的分离效率, 从而加快了O₂的还原和苯酚的降解.     

助剂CuO和La2O3对NiO/α-Al2O3甲烷催化部分氧化制合成气引发过程的影响

采用分步浸渍法制备了NiO/α-Al₂O₃、NiO-CuO/α-Al₂O₃和NiO-La₂O₃/α-Al₂O₃三种催化剂,运用程序升温表面反应（TPSR）技术考察了助剂CuO和La₂O₃对NiO/α-Al₂O₃甲烷催化部分氧化（CPOM）反应引发过程的影响。结果表明,无论是否经过预还原处理,NiO/α-Al₂O₃催化剂在CH₄/O₂混合气氛下进行程序升温表面反应（CH₄/O₂-TPSR）时,即使升高到910℃也不能引发CPOM反应。添加助剂CuO或La₂O₃后,NiO-CuO/α-Al₂O₃和NiO-La₂O₃/α-Al₂O₃催化剂在CH₄/O₂-TPSR过程中均可以引发CPOM反应。原因分别是CuO促进了CH₄对NiO的还原以及抑制了O₂对Ni0的再氧化,La₂O₃减小了Ni晶粒粒径和还原时扩散阻力促进NiO的还原。     

In2O3/ZrO2-TiO2空心球复合材料的制备与光解水制氢性能

以聚苯乙烯(PS)胶球为模板, 通过一步法结合煅烧后处理制备了空心球复合材料In₂O₃/ZrO₂-TiO₂. 采用X射线衍射(XRD)、 X射线光电子能谱(XPS)、 扫描电子显微镜(SEM)、 紫外-可见漫反射吸收光谱(UV-Vis DRS)和氮气吸附-脱附等测试手段对复合材料的结构、 组成和形貌进行了表征. 结果表明, In₂O₃/ZrO₂-TiO₂复合材料的晶型结构以锐钛矿型TiO₂为主, 同时存在少量含有Ti—O—Zr键的混合氧化物. 该复合材料经聚苯乙烯模板处理后呈现空心球状结构, 球壁由纳米粒子堆积而成. In₂O₃/ZrO₂-TiO₂空心球复合材料的比表面积较大(66.92 m²/g), 且In₂O₃与ZrO₂-TiO₂复合后光吸收发生了红移. 对该复合材料光解水制氢性能的研究结果表明, 空心球状In₂O₃/ZrO₂-TiO₂具有较好的产氢效果(56.7 μmol/g, 8 h), 明显高于P25、 ZrO₂、 空心球状ZrO₂-TiO₂及粉末状In₂O₃/ZrO₂-TiO₂.     

负载型铂催化剂中的载体效应

本文用程序升温热脱附法和氢氧滴定法研究了SiO₂、SiO₂·Al₂O₃、Al₂O₃、SiO₂·SnO₂和Al₂O₃·SnO₂等和Pt的相互作用,表明Pt和载体作用强弱的顺序为:Al₂O₃>SiO₂·Al₂O₃>SiO₂;发现SnO₂具有强化SiO₂和Al₂O₃载体效应的作用;提出Pt和载体相互作用较强部位可能是Pt和缺氧氧化物所形成的表面络合物--Pt-[Al₂O_x]和Pt-[SnO_x]。     

Cu/Co/Mn基氧载体释氧动力学及机理研究

以溶胶凝胶法制备了CuO/CuAl₂O₄、Co₃O₄/CoAl₂O₄以及Mn₂O₃/Al₂O₃氧载体,在流化床反应器中CO₂气氛下研究了不同温度下氧载体释氧特性,并通过分析得到各氧载体的释氧动力学机理函数、活化能及指前因子等重要参数。释氧过程中,氧载体CuO/CuAl₂O₄中CuO、CuAl₂O₄均为活性相,释氧后转化为Cu₂O及CuAlO₂,而Co₃O₄/CoAl₂O₄及Mn₂O₃/Al₂O₃中CoAl₂O₄和Al₂O₃均为惰性相,仅有Co₃O₄和Mn₂O₃参与释氧并分别转化为CoO和Mn₃O₄。三种氧载体的释氧过程均可由成核-核生长机理描述,释氧初期氧载体经化学反应形成新的活性核心,随后活性核心聚集形成还原态的氧载体团簇。各氧载体释氧的机理函数G(x)有不同的表达式,CuO/CuAl₂O₄、Co₃O₄/CoAl₂O₄、Mn₂O₃/Al₂O₃释氧的活化能E分别为226.37、130.06和65.90 kJ/mol,相对应的指前因子A分别为2.99×10⁶、4.96×10³和27.37 s^-1。     

V2O5-Sb2O3-TiO2催化剂 低温NH3还原NO及其抗H2O和SO2毒化性能

浸渍法制备了催化剂V₂O₅-Sb₂O₃-TiO₂,考察了V₂O₅、Sb₂O₃负载量、pH值和焙烧温度对催化剂V₂O₅- Sb₂O₃-TiO₂低温氨选择性催化还原(SCR)NO活性的影响;同时,考察了催化剂V₂O₅-Sb₂O₃-TiO₂抗H₂O和SO₂毒化性能。结果表明,V₂O₅和Sb₂O₃负载量分别为5%和2%、焙烧温度为400℃、pH值为4时,催化剂SCR活性最好,反应温度220℃时,可达97%。Sb₂O₃的加入不仅能增强V₂O₅/TiO₂的催化活性,而且能明显提高催化剂的抗H₂O和SO₂毒化性能。SO₂、NO吸附暂态反应和TG-DTG测试表明,Sb₂O₃的促进机制主要是促进了催化剂在SO₂存在条件下对NO的吸附,同时,减弱了硫酸铵盐与催化剂之间的相互作用,硫酸铵盐更容易分解。     

不同形貌Ni/γ-Al2O3催化剂催化CO甲烷化反应的研究

采用沉淀法分别以乙二醇、水、乙二醇-聚乙二醇600为修饰剂,制备了形貌分别为棒状（a-NiO）、粒状（b-NiO）和片状（c-NiO）结构的NiO催化剂,然后和γ-Al₂O₃通过研混法制得NiO/γ-Al₂O₃催化剂。采用XRD、TEM及H₂-TPR等技术手段对催化剂进行了表征。TEM观察NiO的形貌分别为棒状、粒状和片状。H₂-TPR结果表明,NiO/γ-Al₂O₃催化剂的氧化中心数量顺序为b-NiO/γ-Al₂O₃＜a-NiO/γ-Al₂O₃＜c-NiO/γ-Al₂O₃。XRD结果表明,NiO/γ-Al₂O₃催化剂还原后的Ni晶粒尺寸大小为b-Ni＞a-Ni＞c-Ni。在连续流动固定床反应装置上考察了Ni/γ-Al₂O₃对CO甲烷化反应的催化活性,研究了混合方法和形貌对CO甲烷化反应的影响。结果表明,研混法制得催化剂的活性及稳定性较好。催化剂形貌对CO甲烷化反应的催化活性顺序为c-Ni/γ-Al₂O₃＞a-Ni/γ-Al₂O₃＞b-Ni/γ-Al₂O₃,常压、593K和2500h^-1反应条件下,w_Ni为15% c-Ni/γ-Al₂O₃催化CO合成CH₄选择性及CO转化率分别达90.80%和99.63%。     

气相色谱法研究配位化合物的热稳定性(Ⅶ)——Ni(Ⅱ)、Co(Ⅱ)草酸配合物的热分解及产物的催化性能

镍(Ⅱ)、钴(Ⅱ)草酸配合物在氢气中热分解时产生CO₂和CO,并发生加氢催化反应.CoC₃O₄和NiC₂O₄的分解产物CO₂加氢活性很快降低;K₂O等具有分散金属的作用。CoC₂O₄/Al₂O₃和K₂^{[Co(C₂O₄)₂]}/Al₂O₃体系具有Al₂(C₃O₄)₃的分解特征。C₂O₄^2-在Al₂O₃表面能形成表面配合物,在Al₂O₃表面Co(Ⅱ)的还原较为困难。     

氧化物气敏半导体与H2O(g)、O2(g)及还原性气体相互作用的研究

本文系统地研究了SnO₂系和γ-Fe₂O₃元件在变温过程中与H₂O(g)、O₂(g)和还原性气体相互作用的规律。结果表明:Al₂O₃、MgO、Pd、Pt和Sb₂O₃均对元件的体电阻均有调制作用。Al₂O₃是以微粒状存在于元件内,它为元件提供了活化中心,提高了元件的灵敏度。而γ-Fe₂O₃具有超微细结构。     

锅炉结渣初始沉积层微观沉积机理研究

选取矾土Al₂O₃和赤铁矿Fe₂O₃,对这两种矿物做弹性常数的微观分析、对比,X射线衍射分析表明,煤灰与初始沉积层中的矿物种类相同,但两者中矾土Al₂O₃和赤铁矿Fe₂O₃的含量相差很大。采用第一性原理(first-principles)的超软赝势平面波方法,对Al₂O₃和Fe₂O₃的电子结构、弹性常数进行了计算。结果表明,从两种物质的结构角度分析,Al₂O₃晶体中Al³⁺、O^2-的堆积排列相对于Fe₂O₃中Fe³⁺、O^2-要稀疏,这是它们性质不同的结构原因;对于两晶体在<100>方向和切向上的化学键, Fe-O键比Al-O键更容易变形或者断裂,从而导致Fe₂O₃极易沉积在清洁水冷壁上;对Fe₂O₃,切向面对其沉积起了关键性的作用。     

水中有机磷化合物光解测定的研究

本文利用1000W高压汞灯,研究了水中有机磷化合物的光解反应条件、共存有机物的干扰及光解反应速度等问题。结果表明,在pH=3.0时,以过硫酸钾为光解氧化剂,辐射10分钟,即可使水中有机磷化合物定量分解为磷酸根。可用于水中有机磷的测定,此法简单、快速,对实际水样测定结果的平均回收率为82.5-106％。     

UV-Vis/H2O2/草酸铁络合物法在水处理中的应用

介绍了各光Fenton法的运行机理及存在的优缺点,综述了UV-Vis/H₂O₂/草酸铁络合物法在水处理中的应用状况,并对其今后的发展趋势进行了阐述.UV-Vis/H₂O₂/草酸铁络合物法是一种新的高级氧化技术,是对光Fenton法的发展,在处理高浓度难降解有机废水方面效果优于UV/Fe²⁺/H₂O₂法、UV/H₂O₂法、TiO₂法和WO₃法等,因其具有一定的利用太阳能的潜力,所以具有较好的应用前景.     

Ce/Zr物质的量比对Ru/CexZr1-xO2催化剂的性质及其湿式氧化苯酚性能的影响

采用溶胶凝胶法制备了系列不同Ce/Zr物质的量比的Ru/Ce_xZr_1-xO₂催化剂,通过X射线衍射（XRD）、氮气吸附-脱附、拉曼（Raman）光谱、储氧能力（oxygen storage capacity,OSC）、热重（TG）以及吡啶红外（Py-FTIR）等手段对其进行了表征,考察了该催化剂在湿式氧化苯酚反应中的性能。结果表明,ZrO₂可与CeO₂形成固溶体;随着ZrO₂掺杂量的增加,Ce_xZr_1-xO₂固溶体的OSC值增大。相比于CeO₂,掺杂ZrO₂后催化剂表面的L酸量明显增多。催化剂湿式氧化（catalytic wet air oxidation,CWAO）性能与OSC和表面酸性均有密切的关系：催化剂表面的L酸有利于苯酚氧化生成CO₂,而OSC过高会导致催化剂表面积炭,使催化剂失活。当ZrO₂掺杂量为25%时,在160℃、2 MPa纯氧条件下,催化氧化苯酚5 h后,苯酚转化率和总有机碳（total organic carbon,TOC）去除率分别为100%和99%,说明该催化剂具有优异的苯酚氧化性能。     

可见光光解H2S产H2的研究——Rh2O3/CdS悬浮体系中硫化物水溶液的光解

在半导体粉末悬浮体系光解水研究中,最常用的半导体粉末是CdS和TiO₂。前者光谱响应好,可见光即可激发,但易于光腐蚀;后者稳定性好,但禁带宽,仅紫外光可激发。从不同角度改善这二者的性能,一直为人们所关注。在CdS上沉积RuO₂,并选择适宜的反应以抑制CdS的光腐蚀^[1];应用掺杂的方法,使TiO₂的光谱响应扩展至可见区,已取得进展。     

熔盐辅助微波法制备g-C3N4包覆MgO-Al2O3-Fe2O3异质结催化剂及其光催化制过氧化氢性能

H₂O₂ is industrially produced by the anthraquinone method, in which energy consumption is high because it involves multistep hydrogenation and oxidation reactions. Photocatalytic production of H₂O₂ has received increasing attention as a sustainable and eco-friendly alternative to conventional anthraquinone-based and electrochemical production processes. Herein, we report a novel molten salt-assisted microwave process for the synthesis of a g-C₃N₄-coated MgO-Al₂O₃-Fe₂O₃ (MAFO) heterojunction photocatalyst with outstanding H₂O₂ production ability. The addition of a molten salt during synthesis changes the morphology of the as-prepared catalysts and influences the degree of polycondensation of melamine, leading to a change in the band gap energy. The cladding structure forms the maximum area of the heterojunction, leading to strong electronic coupling between the two components. This strong electronic coupling results in a more effective separation of the photogenerated electron-hole pairs and a faster interfacial charge transfer, leading to higher H₂O₂ formation rate. The equilibrium concentration and formation rate of H₂O₂ over the as-prepared heterojunction catalyst were 6.3 mmol·L^-1 and 1.42 mmol·L^-1·h^-1, which are much higher than that reported for g-C₃N₄ and MAFO individually. In addition, the H₂O₂ decomposition rate also decreases over the as-prepared heterojunction catalysts. A possible mechanism and the electron transfer routes have been proposed based on a free radical trapping experiment.     

Design of a novel mitochondria targetable turn-on fluorescence probe for hydrogen peroxide and its two-photon bioimaging applications

Considering that hydrogen peroxide (H₂O₂) plays significant roles in oxidative stress, the cellular signal transduction and essential biological process regulation, the detection and imaging of H₂O₂ in living systems undertakes critical responsibility. Herein, we have developed a novel two-photon fluorescence turn on probe, named as Pyp-B for mitochondria H₂O₂ detection in living systems. Selectivity studies show that probe Pyp-B exhibit highly sensitive response toward H₂O₂ than other reactive oxygen species (ROS) and reactive nitrogen species (RNS) as well as biologically relevant species. The fluorescence colocalization studies demonstrate that the probe can localize in the mitochondria solely. Furthermore, as a bio-compatibility molecule, the highly selective and sensitive of fluorescence probe Pyp-B have been confirmed by its cell imaging application of H₂O₂ in living A549 cells and zebrafishes under the physiological conditions.     

Fabrication of high performance thin films from metal fluorocomplex aqueous solution by the liquid phase deposition

The hetro-structured oxide thin films from metal fluorocomplex solution have been prepared by the liquid phase deposition (LPD) method. The Pt/Nb₂O₅ and Au/Nb₂O₅ composite films can be prepared from a mixed solution of niobium source, H₃BO₃, Pt(NH₃)₄Cl₂ and HAuCl₄ aqueous solutions under the ambient temperature and atmosphere. In the case of Au/SiO₂ composite film, (NH₄)₂SiF₆ solution is used as a mother solution. The Pt and Au ionic species are deposited in Nb₂O₅ and SiO₂ matrices. They are reduced to their metallic state after treatment above 200 °C. The size of dispersed particles can be controlled by heat treatment temperature. It is also clear that, gold nanoparticles are also found to interact with SiO₂, although the interaction is smaller than that with Nb₂O₅ showing the size of Au nanoparticles remain smaller in Nb₂O₅ that in SiO₂.     

Co3O4/UiO-66@α-Al2O3陶瓷膜对VOCs废气的分离催化性能

以α-Al₂O₃为支撑层, UiO-66为分离层, Co₃O₄为催化层, 构建了Co₃O₄/UiO-66@α-Al₂O₃陶瓷膜.对其形貌结构进行了表征, 并研究了其对挥发性有机物(VOCs)的分离催化性能. 结果表明, 该陶瓷膜对喷涂行业废气中苯与吡啶两种主要成分体现出良好的分离性, 透过侧的气体中吡啶与苯的摩尔浓度比值可由给料侧的1提高至17; 体系中引入臭氧后, 给料侧苯的浓度明显降低, 其去除率可达到89%. 透过侧的吡啶去除率仅为27%, 得到了较大程度的保留, 剩余的吡啶经收集后可进行单独的深度处理. Co₃O₄/UiO-66@α-Al₂O₃陶瓷膜在对喷涂行业废气中苯成分高效降解的同时, 能够有效解决喷涂行业废气处理过程中氮氧化物的排放问题, 有望成为喷涂行业废气预处理工艺的理想选择.     

Ultraviolet stimulation of hydrogen peroxide production using aminoindazole, diaminopyridine, and phenylenediamine solid polymer complexes of Zn(II)

Hydrogen peroxide (H₂O₂) is a valuable chemical commodity whose production relies on expensive and energy intensive methods. If an efficient, sustainable, and inexpensive solar-mediated production method could be developed from the reaction between dioxygen and water then the use of H₂O₂ as a fuel may be possible and gain acceptance. When concentrated at greater than 10 M, H₂O₂ possesses a high specific energy, is environmentally clean, and is easily stored. However, the current method of manufacturing H₂O₂ via the anthraquinone process is environmentally unfriendly making the unexplored nature of its photochemical production at high concentration from solar irradiation of interest. Towards this end, we studied the concentration and quantum yield of hydrogen peroxide produced in an ultraviolet (UV-B) irradiated environment using solid, Zn(II)-centered, complexes of amino-substituted isomers of indazole, pyridine, and phenylenediamine to catalyze the reaction. Aqueous suspensions in contact with air were exposed to 280–360-nm light from a low-power lamp. Of the ten complexes studied, Zn-5-aminoindazole had the greatest first-day production of 63 mM/day with a 37% quantum yield and p-phenylenediamine (PPAM) showed the greatest long-term stability. Isomeric forms of the catalysts’ organic components (e.g., amino groups) affected H₂O₂ production. For example, irradiation of diaminopyridine isomers indicated 2,3-diamino and 3,4-diamino structures were the most productive, each generating 32 mM/day H₂O₂, whereas the 2,5-diamino isomer generated no H₂O₂. A significant decrease in H₂O₂ production with time was observed for all but PPAM, suggesting the possibility of a catalyst-poisoning mechanism. We propose a reaction mechanism for H₂O₂ production based on the stability of the resonance structures of the different isomers.     

Hydrothermal Synthesis of H3PW12O40/TiO2 Nanometer Photocatalyst and Its Catalytic Performance for Methyl Orange

H3PW12O40/TiO2 nanometer photocatalyst was prepared by one step hydrothermal synthesis from H3PW12O40′nH2O and Ti(OBu)4,simultaneously realizing the load and modification of H3PW12O40.The catalyst was ...