Preparation of M2O3-CeO2(M=La,Fe,and Al) Compoundoxide Catalyst and Its Degradation Performance

As one of the most active rare earths,CeO2 has caused extensive concern due to its multifunctional properties.CeO2-based compound oxide of M2O3-CeO2(M=La,Fe,and Al)were prepared by coprecipitation and impregnation methods.The photocatalytic performance of the samples for the degradation methylene blue was studied under UV and visible light irradiation.The effects of constituents on the properties of the CeO2-based catalysts were investigated by XRD,TEM,BET,and UV-Vis spectrophotometer.The highest degradation of methylene blue under 230W UV light was almost 100%at 50 min by La2O3/Fe2O3-CeO2/γ-Al2O3 catalyst and 99.42%at 50 min by Fe2O3-CeO2/γ-Al2O3 catalyst.The methylene blue removal efficiency under indoor natural light reaches 93.81%by La2O3/Fe2O3-CeO2/γ-Al2O3 catalyst and 92.34%by Fe2O3-CeO2/γ-Al2O3 catalyst at 50 min.The order of catalytic degradation activity is La2O3/Fe2O3-CeO2/γ-Al2O3>Fe2O3-CeO2/γ-Al2O3>La2O3-CeO2/γ-Al2O3>Al2O3,owing to their structural features.The doping of La^3+or Fe3+onto CeO2/γ-Al2O produced much more oxygen vacancies under light irradiation and reduced the energy laps of CeO2 with value of 2.86 ev,which improved the photocatalytic redox performance of the composite oxide.

Reduction of Sulphur-containing Aromatic Nitro Compounds with Hydrazine Hydrate over Iron(III) Oxide-MgO Catalyst

Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron（Ⅲ） oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.

Direct decomposition of nitric oxide in low temperature over iron-based perovskite-type catalyst modified by Ru

Iron-based perovskite-type compounds modified by Ru were prepared through sol-gel process to study its catalytic activity of NOx direct decomposition at low temperature and evaluate the conversion of NO under the experimental conditions. The catalytic activity of La 0.9Ce 0.1Fe 0.8-nCo 0.2RunO3 （n=0.01,0.03,0.05,0.07,0.09）series for the NO, NO-CO two components, CO-HC-NO three components were also analyzed. The catalytic investigation evidenced that the presence of Ru is necessary for making highly activity in decomposition of nitric oxide even at low temperature（400 ℃）and La 0.9Ce 0.9Fe 0.75Co 0.2Ru 0.05O3 （n=0.05） has better activity in all the samples, the conversion of it is 58.5%. With the reducing gas（CO,C3H6）added into the gas, the catalyst displayed very high activity in decomposition of NO and the conversion of it is 80% and 92.5% separately.

Pd Pt VO_(x)/CeO_(2)-ZrO_(2):Highly efficient catalysts with good sulfur dioxide-poisoning reversibility for the oxidative removal of ethylbenzene

The PdPtVO_(x)/CeO_(2)-ZrO_(2)(PdPtVO_(x)/CZO)catalysts were obtained by using different approaches,and their physical and chemical properties were determined by various techniques.Catalytic activities of these materials in the presence of H_(2)O or SO_(2)were evaluated for the oxidation of ethylbenzene(EB).The PdPtVO_(x)/CZO sample exhibited high catalytic activity,good hydrothermal stability,and reversible sulfur dioxide-poisoning performance,over which the specific reaction rate at 160℃,turnover frequency at 160℃(TOF_(Pd or Pt)),and apparent activation energy were 72.6 mmol/(g_(Pt)·sec)or 124.2 mmol/(g_(Pd)·sec),14.2 sec^(-1)(TOF_(Pt))or 13.1 sec^(-1)(TOF_(Pd)),and 58 k J/mol,respectively.The large EB adsorption capacity,good reducibility,and strong acidity contributed to the good catalytic performance of PdPtVO_(x)/CZO.Catalytic activity of PdPtVO_(x)/CZO decreased when 50 ppm SO_(2)or(1.0 vol.%H_(2)O+50 ppm SO_(2))was added to the feedstock,but was gradually restored to its initial level after the SO_(2)was cut off.The good reversible sulfur dioxide-resistant performance of PdPtVO_(x)/CZO was associated with the facts:(i)the introduction of SO_(2)leads to an increase in surface acidity;(ii)V can adsorb and activate SO_(2),thus accelerating formation of the SO_(x)^(2-)(x=3 or 4)species at the V and CZO sites,weakening the adsorption of sulfur species at the PdPt active sites,and hence protecting the PdPt active sites to be not poisoned by SO_(2).EB oxidation over PdPtVO_(x)/CZO might take place via the route of EB→styrene→phenyl methyl ketone→benzaldehyde→benzoic acid→maleic anhydride→CO_(2)and H_(2)O.

Synthesis of Tungstophosphates of Heteropoly Compound and Its Catalytic Property in Oxidative Desulfurization of Diesel

Several kinds of Tungstophosphates of Heteropoly Compounds （TPHC） with different compositions and the same structure were synthesized using the method of solid-phase reaction to change the tool ratio of Na4P2O7·10H2O, WO3 and Na2WO4 · 2H2O. TPHC, as a catalyst, was used in oxidative desulfurization of diesel. The results show that TPHC has catalytic activity. With THPC existing, the highest desulfurization rate reaches 51.85%, 32.6% higher than that yield without TPHC. And the desulfiarization rate increases with decreasing WO3. FT-IR spectra of TPHC shows that the catalytic activity is related to the activity of end oxygen（Od）.The more active Od is, the stronger the capability of obtaining or losing electron is. It means that TPHC has a good catalytic activity. FT-IR spectra of TPHC indicates that desulfurization rate is in linear correlation with Iw-Od/Ip-Od/ Iw-Od is intensity of W-Od vibration band, Ip-Od is intensity of P-Od vibration band） and correlation coefficient reaches 0.965.

Preparation and Water-Gas Shift Catalytic Activities of the Perovskite Type Complex Oxide La_(1-x) Ce_xFeO_3

The perovskite type rare earth iron complex (REIC) oxide La 1-x Ce xFeO 3 is designed and prepared as water gas shift catalyst. Activity evaluation and heat resisting test show that the perovskite type compounds La 1-x Ce xFeO 3(·K) has a good thermal stability if x is less than or equal to 0.5 . But when x is greater than 0.5 , La 1-x Ce xFeO 3(·K) will turn out to be ceria and magnetite partially or completely at high temperature in the shift reaction atmosphere. In the case of x=0.5, the conversion of carbon monoxide is about 68% at 530 ℃. Potassium can greatly improve the low temperature activity, but slightly lower the high temperature activity, and has little impact on the thermal stability. La 0.5 Ce 0.5 FeO 3 (·K) is a promising chromium free high temperature shift catalyst.

催化氧化VOCs催化剂中毒机制研究进展

催化氧化法是目前处理挥发性有机物(VOCs)最有效的治理技术之一,但催化剂中毒问题阻碍着催化剂的应用与催化氧化技术的发展。本文介绍了催化氧化VOCs催化剂中毒机制,综述了进行VOCs催化氧化反应的活性测试以及对失活的催化剂进行分析表征两种研究催化剂中毒方法的研究进展。指出:设计出针对性强、抗中毒性能良好且具有大规模工业应用前景的催化剂将是未来的研究方向。

Structural regulation of single-atom catalysts for enhanced catalytic oxidation performance of volatile organic compounds

The catalytic oxidation of volatile organic compounds(VOCs)is considered a feasible method for VOCs treatment by virtue of its low technical cost,high economic efficiency,and low additionally produced pollutants,which is of important social value.Singleatom catalysts(SACs)with 100%atom utilization and uniform active sites usually have high activity and high product selectivity,and promise a broad range of applications.Precise regulation of the microstructures of SACs by means of defect engineering,interface engineering,and electronic effects can further improve the catalytic performance of VOCs oxidation.In this review,we introduce the mechanisms of VOCs oxidation,and systematically summarize the recent research progress of SACs in catalytic VOCs total oxidation into CO_(2)and H_(2)O,and then discuss the effects of various structural regulation strategies on the catalytic performance.Finally,we summarize the current problems yet to be solved and challenges currently faced in this field,and propose future design and research ideas for SACs in catalytic oxidation of VOCs.

催化氧化催化剂在合成橡胶尾气处理上的应用

以100 kt/a热塑性弹性体装置尾气处理系统为应用对象,对国内自主研发的VOCPlus型催化氧化催化剂进行了性能评价,并考察了其实际应用效果。结果表明,VOCPlus型催化氧化催化剂具有起燃温度低及高温稳定性好和水热稳定性较强的特点。在催化剂入口温度约372℃、反应温度428℃、非甲烷总烃质量浓度1 500 mg/m^(3)的条件下,尾气处理系统反应器出口的非甲烷总烃质量浓度可达6.2 mg/m^(3),总烃去除率维持在99%以上。橡胶装置尾气处理系统至目前已稳定达标运行超过1.5 a,满足该系统对于长周期运行的要求。

Catalytic steam methane reforming enhanced by CO_2 capture on CaO based bi-functional compounds

Sorption enhanced steam methane reforming（SE-SMR） was performed to maximize hydrogen production and contemporary remove COfrom the product stream using bi-functional sorbent-catalyst compounds.Samples were tested at two different scales: micro and laboratory. The CaO amount varied in the CaO-CaAlOsorbent system synthesized by wet mixing(CaO content of 100 wt%, 56 wt%, 30 wt%, or 0 wt% and balance of CaAlO) which were upgraded to bi-functional compounds by impregnation of 3 wt% of Ni. Nitrogen adsorption（BET/BJH）, X-Ray Diffraction（XRD）, Temperature-Programmed Reduction（TPR） and Scanning and Transmission Electronic Microscopy（SEM and TEM, respectively） analyses were performed to characterize structural and textural properties and reducibility of the bi-functional materials and evaluate their catalytic behavior. A fixed sorbent composition CaO-CaAlO(56 wt% of CaO and CaAlObalance), was chosen to study the effect of different weight hourly space times（WHST） and CHstream compositions in SE-SMR activity. Impregnated mayenite at both micro and laboratory scales showed stable Hcontent of almost 74%, with CHconversion of 72% similarly to the values reported by the sample containing 30 wt% of CaO in the post-breakthrough.Sample with 30 wt% of CaO showed promisingly behavior, enhancing Hcontent up to almost 94.5%.When the sorption enhanced reaction is performed roughly 89% of CHconversion is achieved, and after the pre-breakthrough, the catalyst worked at the thermodynamic level. During cycling sorption/regeneration experiments, even if COremoval efficiency slightly decreases, CHconversion and Hyield remain stable.

Simple Preparation of Crystal Co_3(BTC)_2·12H_2O and Its Catalytic Activity in CO Oxidation Reaction

Crystalline metal-organic framework cobalt （II） benzenetricarboxylate C%（BTC）2·12H2O （MOF-Co） has been prepared using solvothermal method. The reaction of cobalt （II） nitrate and 1,3,5-benzenetriearboxylic （BTC） acid in a mixed solution of N,N-dimethylformarnide （DMF）/C2H5OH/H2O （1：1：1, v/v） at low temperature for short reaction times produced this crystalline compound. Compared with traditional hydrothermal method, a mixed solution method for the synthesis of crystalline metal complex was found to be highly efficient. After water molecules were removed from this metal complex, its exposed nodes served as active sites. When this MOF-Co was employed in the oxidation of CO, it showed good catalytic properties causing 100% conversion of CO to CO2 at low temperature of 160 ℃.

分子筛去除VOCs的研究进展

目前,吸附及催化氧化技术是去除挥发性有机化合物(VOCs)最为高效、经济、环境友好的方法。分子筛具有较大的比表面积、规整的微孔孔道和稳定的结构,因此其作为吸附剂及催化剂在工业VOCs的去除过程中有重要的应用价值。本文总结了近年来分子筛吸附VOCs的规律性研究以及分子筛微结构和表面性质对催化氧化的影响。其中影响吸附VOCs的关键因素包括分子筛拓扑结构、阳离子类型、孔道多极化、亲疏水性等;针对催化氧化技术,主要讨论了负载贵金属/非贵金属的分子筛催化剂,其中获得高效催化氧化VOCs催化剂的关键在于以下几个方面:以结构形貌适宜的分子筛载体为基础,构建有效调控金属物种粒子尺寸的制备方法;调控活性物种的化学状态及其与分子筛载体的相互作用;深入理解分子筛微结构、活性物种的状态等因素对催化性能的影响。

负载型贵金属催化剂催化氧化VOCs的研究进展

挥发性有机物(VOCs)可引起光化学烟雾,并严重损害人类健康,威胁人类社会的可持续发展,亟需对其进行去除。鉴于高效、经济和无二次污染等优势,催化氧化被认为是去除VOCs的有效途径之一。综述了负载型贵金属催化剂催化氧化VOCs的反应机理,分析了贵金属种类和载体性质对VOCs催化氧化活性的影响,总结了催化剂的结构与性能之间的关系,可为高效催化剂的设计与开发提供理论依据。

协同脱除燃煤电厂烟气中NO和VOCs的SCR催化剂研究进展

燃煤电厂的NO_(x)和VOCs排放量占人为源排放量的近三成,是大气环境治理面临的严峻挑战。在燃煤电厂的SCR区域协同脱除烟气中NO和VOCs,可以有效降低处理成本,具有重要的科学价值和环境效益。本文概述了近年来协同脱除燃煤电厂烟气中NO和VOCs的SCR催化剂的研究进展。当前研究主要采用浸渍法、共沉淀法、水热法、溶胶-凝胶法、模板法等方法制备多功能催化剂,掺杂过渡金属/贵金属或选择合适的载体会明显提高催化剂表面酸性位点数量和表面活性氧浓度,使催化剂协同脱除能力大幅攀升。然而,实际烟气中多种污染物会在催化剂表面相互影响,多种反应物的相互作用机理以及反应条件对协同去除率的影响也被重点讨论。针对当前研究存在的问题和挑战,可利用原位技术和DFT两个有力的工具,探究催化剂协同催化反应路径和失活机理,从而指导设计结构稳定、氧化还原活性好、副产物少、抗毒性强、可再生的协同脱除NO和VOCs的SCR催化剂。当前协同脱除NO和VOCs的研究还停留在实验室规模,未来要完善多污染物协同控制理论,实现复杂烟气中NO_(x)和VOCs协同脱除的实际工程应用。

微反应器共沉淀反应制备铜锰催化剂

在Caterpillar微反应器中采用共沉淀法制备了不同铜锰比的共沉淀物,直接焙烧得到铜锰复合氧化物催化剂。采用X射线衍射(XRD)、热重分析(TG)、拉曼光谱(Raman)和X射线光电子能谱(XPS)对沉淀物和催化剂进行了物相和结构分析。结果显示,随着Cu含量的增加,催化剂中Mn3+所占比例逐渐下降,表面晶格氧含量呈现先上升后下降的趋势,催化甲苯降解的活性呈现先上升后下降的规律。微反应器中的流动反应特性使得催化剂中的Cu、Mn保持良好分散性,有利于提高催化剂中Mn3+含量,此时表面晶格氧成为催化活性的制约因素。

双金属催化剂催化氧化VOCs的研究进展

挥发性有机物(VOCs)是一类对环境和人体健康产生威胁的有毒有机化合物。催化氧化法因其高效、环保和去除率高等优点被认为是目前最有效的VOCs消除方法之一,负载双金属催化剂由于良好的催化性能被应用于挥发性有机物的去除。综述了近年来负载双贵金属、双非贵金属和混合金属催化剂对VOCs的催化性能,分析典型催化剂对VOCs氧化催化性能的影响,并展望VOCs催化氧化的未来发展趋势。

基于C-TiO_(2)@Fe_(3)O_(4)/AC的光催化耦合臭氧氧化技术对水体中苯胺的降解

苯胺是一种典型的有毒污染物,在工业废水中较为常见,而常规处理技术对其处置效果不佳。光催化耦合臭氧高级氧化技术因为高效快速,具有广泛的应用前景,可以作为有毒有机污染物的处置手段之一。通过制备了一种C改性TiO_(2)负载磁性活性炭(C-TiO_(2)@Fe_(3)O_(4)/AC)催化剂,考察了其光催化耦合臭氧氧化处理苯胺的效果。研究结果表明,运行30min后即可达到95%以上的降解效率,苯胺去除率和反应效率均高于普通的C-TiO_(2)和Fe_(3)O_(4)/AC催化剂。

VOCs热催化氧化技术中整体式催化剂的研究进展

热催化氧化法是目前最具发展前景的挥发性有机化合物(VOCs)处理技术之一。其中作为技术核心的整体式催化剂具有优异的传质、传热性能和热稳定性,因而备受关注。本文梳理了不同类型整体式催化剂的研究现状,展望了其发展趋势。指出:开发低成本、高抗水性和高抗毒性的整体式催化剂是其未来的发展方向;如何维持催化剂的再生循环性能,提高催化剂的使用寿命,也是整体式催化剂发展过程中迫切需要解决的重要问题。