三维电催化氧化法的研究进展与应用

主要论述了三维电催化氧化法的研究进展。分别论述了三维电催化在处理工业有机废水的研究现状,三维电催化氧化的反应机理。报告了三维电催化反应装置研究现状;分析了电极材料,粒子电极的填充方式,反应装置类型对废水处理效果的影响,主要介绍了活性炭(GAC)材料作为粒子电极的应用研究,并探讨了三维电催化技术与其它技术联用提高废水处理效率的研究,最后对三维电催化氧化法的研究方向进行了展望。     

电极材料在电催化氧化处理有机废水中的应用

电极材料是电催化氧化处理有机废水技术的关键。综述了金属、活性碳纤维、金属氧化物几种电极材料对有机废水的降解效果,并展望了电催化氧化处理有机废水中电极材料的发展方向。     

三维电催化技术反应机理及其应用研究

综述了近几年国内外对三维电催化技术的研究进展，详细总结了该技术的基本反应机理，系统地分析了三维电催化技术中电极材料对废水处理效果的影响，介绍了负载型粒子电极的应用研究，探讨了该技术在不同废水处理中的应用情况，以及与其他处理技术耦合应用研究，展望了三维电催化技术的研究前景。     

三维电极电化学技术及其在废水处理中的应用

针对三维电催化氧化工艺的应用及进展进行了综述。介绍了三维电催化氧化技术的概念,并且以废水中氨氮污染物的处理探究了该技术的降解机理;简要概括了三维电催化氧化技术的影响因素,如电池电压和电流密度、初始pH、温度等;阐述了三维电催化氧化的典型电极材料,主要是通过构建中间层及涂层多元化改性的DSA电极、改性的掺硼金刚石电极、传统粒子电极和近年来研究热门的负载型粒子电极;分别总结了三维电催化氧化技术在氨氮废水、苯酚废水及印染废水处理方面的应用现状,提出了三维电催化氧化技术目前存在的问题并且对该技术今后的发展方向做出了展望。     

电催化氧化处理有机废水阳极材料的研究进展

水体中存在的微量有机污染物对人类及生物的正常生命活动构成了严重威胁,有效去除这些污染物已成为当务之急。电催化氧化技术因具有适应性广,氧化性强,无二次污染,反应迅速,设备及其操作简单等优点而日益成为有机废水处理领域的研究热点。阳极材料是电化学氧化法处理有机废水的关键。文章综述了贵金属电极、碳素电极、钛基金属氧化物电极和合成掺硼金刚石薄层电极等常用阳极材料的性能,并对有机废水电催化氧化阳极材料的发展趋向进行了展望。     

金属氧化物电极材料在降解含酚废水中的应用

电极材料是电化学催化氧化技术的核心,直接决定着酚类化合物的降解机理、降解历程和降解效果.综述了PbO_2、SnO_2和其它金属氧化物电极材料对含酚废水的降解效果.介绍了提高PbO_2和SnO_2电极催化活性的方法并阐述了其失活机理与延长寿命的途径.指出寻找廉价、稳定性好、析氧超电势高、催化活性好的电极材料是电催化氧化降解含酚废水的主要研究方向.     

难降解废水污染治理中DSA电极的优化研究进展

电催化氧化法氧化能力强、占地面积小、易于控制，应用前景十分广阔。阳极作为影响污染物电催化氧化效率与路径的最主要因素，是提升电催化性能的重要突破口，引起了国内外学者的广泛关注与研究，以期制备出具备高效稳定催化活性和较低成本的理想阳极。按照电催化基本原理、活性涂层分类、制备方法优化、改性探究与研究展望，综述了近年来工业相关领域最常用的DSA电极优化研究现状，从替换活性涂层、掺杂材料和提高析氧电位，降低能耗两个角度分析了如何控制成本，通过制备方法条件与电极改性两个方面探讨了如何提高稳定性与电催化活性，同时叙述了掺杂量、电流密度、烧结温度等方面的一些最佳工艺参数，梳理了电极三维结构、新型材料等热门领域的研究情况。并从材料开发、三维孔隙、小试中试等三个方面对未来进行了展望，希望可以对相关研究探索提供一定帮助。     

三维电极技术及其在环境污染治理中的应用

介绍了三维电极技术的分类和工作机理。综合近年来国内外三维电极技术的研究文献,重点阐述了三维电极技术在三维电极反应器、极板材料、粒子电极及与其它技术联用的研究现状,概述了三维电极技术在废水处理和废气治理领域的应用状况。高效反应器和新型三维电催化电极的研制及其联合处理工艺的开发将成为今后该领域研究的重点方向。     

PbO2电极在电催化氧化领域中的应用

电催化氧化技术在废水处理方面拥有反应条件温和、自动化控制、稳定性好、降解迅速、无二次污染等优势,因而成为最有前景的废水处理技术之一。PbO₂电极因其制备简易、析氧电位高、导电性好、耐腐蚀强等特点在电催化领域备受青睐。PbO₂电极在制备过程中往往通过掺杂元素等手段来提高电极的电催化活性,以此来达到更高效的降解污染物。总结了近年来PbO₂电极的制备,重点讨论元素掺杂研究进展,整理不同元素对PbO₂电极的电催化性能改变,并且提出PbO₂电极在未来研究过程中的挑战及机遇。     

RuO_2-SnO_2电极的XPS研究与氧化物表面的酸碱性

研究了RuO_2-SnO_2混合金属氧化物电极,它对NaCl溶液中的析氯反应具有良好的电催化活性及选择性。采用XPS(X射线光电子光谱)研究了电极表画的组成,发现金属阳极〔DSA(Ru-Sn〕表面的钌含量和吸附氯含量均高于DSA(Ru-Ti)。采用电位滴定法研究电极表面酸碱性,测定了零电荷点(PZC)和零电荷点的移动(ΔPZC)的数值,显示了DSA(RuO_2-SnO_2)表面的酸性更强,Cl的特性吸附也更强。由此得出:混合金属氧化物电极的电催化行为与其表面组成及性质存在密切关系。     

Pt修饰的Pd/石墨烯纳米复合材料的制备及对乙二醇氧化反应的电催化活性

以氧化石墨(GO)和Pd(NO₃)₂为原料,通过化学还原法制备Pd纳米粒子-石墨烯(Pd/G)纳米复合材料,然后以H₂PtCl₆作为Pt前体,在Pd纳米粒子的表面恒电位沉积Pt,制备不同Pt负载量的Pd/G(Pt-Pd/G)电极.利用场发射扫描电镜(FE-SEM)、透射电镜(TEM)和X射线能谱仪(EDX)对材料的微观结构进行了表征和分析.结果显示石墨烯上的金属粒子分散均匀,平均粒径约7.2nm.电化学测试结果显示Pt-Pd/G电极对乙二醇电化学氧化反应具有良好的催化性能.当纳米粒子的Pt:Pd原子百分比为1:42时,其反应峰电流密度分别为Pd/G和Pt/G电极的3.0倍和2.7倍.少量的Pt沉淀可显著改进Pd/G电极的催化活性.本研究采用的修饰方法简单,修饰效果明显,可应用于其他金属纳米复合材料的异金属修饰.     

Oxygen evolution on semiconducting oxides

The oxygen evolution reaction is of particular interest to secondary metal air batteries and water electrolysis plants. However, most of the earlier work has been on precious metals and there are no guidelines for the choice of semiconducting oxides as oxygen evolving electrodes. In this study, the role of the metal/metal oxide or the lower metal oxide/higher metal oxide couple in determining the minimum voltage required for the evolution of oxygen is emphasized, together with other essential requirements such as electrical resistivity, electrode microstructure, corrosion resistance and catalytic properties. A survey of various metal oxides based on the above criterion suggested that NiCo₂O₄ is of particular interest and Teflon bonded electrodes based on this material gave over 13000 A/m² at 1.63 V vs dhe, 70°C, 5 N KOH.     

Characterisation and behaviour of Ti/TiO2/noble metal anodes

The morphology, composition and the electrical and electrochemical behaviour of the anodic microporous layer, prepared by the galvanostatic anodisation of Ti after sparking, followed by galvanostatic deposition of Pt or Ir have been investigated. These electrodes are proposed to function as dimensionally stable anodes (DSAs). For Ti/TiO₂/Pt electrodes, Pt is deposited within some of the micropores of the oxide film. In contrast, for Ti/TiO₂/Ir, the metal is deposited preferentially on the top surface. This difference is thought to result from the position of the metal deposition potential with respect to the flat band potential of n-TiO₂. Optical imaging of both types of DSA suggests that only a few sites on the surface are responsible for electron exchange at the DSA-electrolyte interface. C-AFM measurements of Ti/TiO₂/Pt samples subjected to long-term anodic polarisation, suggest that the Ti-noble metal contact is progressively insulated by thickening of the TiO₂ barrier layer, promoting passivation of the DSA. For Ir coated anodes, catalytic activity is directly related to the presence of Ir and to the stability of the catalytic oxide layer. Under Cu electrowinning conditions, the electrochemically formed hydrated Ir oxide was found to be catalytically less stable, than the iridium oxide film subjected to a heat treatment.     

Electrochemical behaviour of metal hexacyanoferrate converted to metal hydroxide films immobilized on indium tin oxide electrodes—Catalytic ability towards alcohol oxidation in alkaline medium

In this work, we demonstrate a simple method to modify indium tin oxide (ITO) electrodes in order to perform electro-catalytic oxidation of alcohols in alkaline medium. Metal hexacyanoferrate (MHCF) films such as nickel hexacyanoferrate (NiHCF) and copper hexacyanoferrate (CuHCF) were successfully immobilized on ITO electrodes using an electrochemical method. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the structural and morphological aspects of MHCF films. Cyclic voltammetry (CV) was used to study the redox properties and to determine the surface coverage of these films on ITO electrodes. Electrochemical potential cycling was carried out in alkaline medium in order to alter the chemical structure of these films and convert to their corresponding metal hydroxide films. SEM and XPS were performed to analyze the structure and morphology of metal hydroxide modified electrodes. Electro-catalytic oxidation ability of these films towards methanol and ethanol in alkaline medium was investigated using CV. From these studies we found that metal hydroxide modified electrodes show a better catalytic performance and good stability for methanol oxidation along with the alleviation of CO poisoning effect. We have obtained an anodic oxidation current density of ∼82 mA cm⁻² for methanol oxidation, which is at least 10 fold higher than that of any metal hydroxide modified electrodes reported till date. The onset potential for methanol oxidation is lowered by ∼200 mV compared to other chemically modified electrodes reported. A plausible mechanism was proposed for the alcohol oxidation based on the redox properties of these modified electrodes. The methodology adapted in this work does not contain costlier noble metals like platinum and ruthenium and is economically viable.     

负载型稀土臭氧氧化催化剂在水处理中的应用进展

非均相催化臭氧氧化技术是一种高效的水污染控制技术。负载型稀土臭氧氧化催化剂因稀土元素独特的电子构型,展现出优异的催化性能,不仅具有良好的稳定性和较长的使用寿命,还可有效解决催化剂流失及出水金属离子超标问题,被认为是最有前景的非均相臭氧氧化催化剂。本文着重从负载型稀土臭氧氧化催化剂的制备、催化反应机理以及单稀土、稀土-过渡金属、双稀土-过渡金属氧化物负载型臭氧氧化催化剂在近几年的污水处理领域中的应用进展进行概述与总结。多稀土复合型非均相臭氧氧化催化剂的开发,以及对催化氧化过程的作用机理的深入研究,是未来非均相催化臭氧氧化技术在水处理中的重点研究方向。     

生物模板法制备金属氧化物及其催化应用研究进展

自然环境中长期进化形成的多层次、多维和多尺度天然硬模板结构和一些具有多层次多维结构的天然“软”生物分子可为多级结构纳米材料的设计与制备提供了新的思路。金属氧化物通常作为催化剂的重要组成部分,其制备与催化应用得到广泛关注,生物模板法为金属氧化物的制备提供了一条简单、绿色、有效的合成路线。本文从基于生物模板的制备方法、生物模板在氧化物制备过程中的作用和生物模板在金属氧化物催化应用时的作用方面总结近十年来的研究进展。基于硬模板的制备方法简单高效,可完美地复制结构类似的金属氧化物材料,而软模板能够灵活地调控金属氧化物颗粒的尺寸和分散性。基于生物模板制备金属氧化物的过程往往经历“吸附-成核-生长-组装”多步骤,生物模板起着表面吸附、空间限域、导向等重要作用。就所得金属氧化物的催化应用而言,生物模板法的优势在于能够实现氧化物材料元素的自掺杂、有效改善传质以及特殊的表面结构赋予催化剂优异的催化性能。     

金属氧化物在OX-ZEO催化剂中催化CO x 加氢制低碳烯烃研究进展

金属氧化物-分子筛（OX-ZEO）双功能催化剂可实现CO _x 加氢制低碳烯烃的高选择性转化。本文概述了OX-ZEO催化CO _x 加氢制低碳烯烃反应中金属氧化物的研究进展,通过对CO _x 加氢制甲醇/乙烯反应热力学分析指出了“接力催化”的优势,重点讨论了金属氧化物的种类和组成、制备方法及金属氧化物和分子筛的“亲密度”对催化性能的影响,探讨了催化反应机理、氧空位的作用及抑制副反应的策略。分析了OX-ZEO催化反应面临的问题和挑战,展望了OX-ZEO催化体系的发展趋势,认为通过元素掺杂、助剂修饰、优化制备条件等可提高金属氧化物的氧空位含量,进而可提高催化活性,也可通过对金属氧化物进行表面疏水改性抑制副产物CO₂,提高C原子利用率。     

涠洲终端脱硫系统改造工艺选择

介绍了涠洲终端油田伴生脱硫系统存在问题和改造的紧迫性;通过对膜分离法、湿法及干法脱硫工艺对比,确定采用W703复合氧化物精脱硫剂干法无氧脱硫工艺来代替原有的湿式催化氧化法脱硫工艺;同时介绍了脱硫方案和工艺特点。     

Functionalizing nanocrystalline metal oxide electrodes with robust synthetic redox proteins

De novo designed synthetic redox proteins (maquettes) are structurally simpler, working counterparts of natural redox proteins. The robustness and adaptability of the maquette protein scaffold are ideal for functionalizing electrodes. A positive amino acid patch has been designed into a maquette surface for strong electrostatic anchoring to the negatively charged surfaces of nanocrystalline, mesoporous TiO(2) and SnO(2) films. Such mesoporous metal oxide electrodes offer a major advantage over conventional planar gold electrodes by facilitating formation of high optical density, spectroelectrochemically active thin films with protein loading orders of magnitude greater (up to 8 nmol cm(-2)) than that achieved with gold electrodes. The films are stable for weeks, essentially all immobilized-protein display rapid, reversible electrochemistry. Furthermore, carbon monoxide ligand binding to the reduced heme group of the protein is maintained, can be sensed optically and reversed electrochemically. Pulsed UV excitation of the metal oxide results in microsecond or faster photoreduction of an immobilized cytochrome and millisecond reoxidation. Upon substitution of the heme-group Fe by Zn, the light-activated maquette injects electrons from the singlet excited state of the Zn protoporphyrin IX into the metal oxide conduction band. The kinetics of cytochrome/metal oxide interfacial electron transfer obtained from the electrochemical and photochemical data obtained are discussed in terms of the free energies of the observed reactions and the electronic coupling between the protein heme group and the metal oxide surface.