贵金属负载TiO_2光催化降解甲苯研究

采用Degussa P25 TiO2粉末,利用光沉积法制备贵金属负载光催化剂M/TiO2(M分别为Pt、Pd、Ag和Au)。通过气相甲苯光催化降解实验考察M/TiO2的光催化活性。实验结果表明:负载1.0 wt%的Pt、Pd、Ag和Au四种贵金属均可提高TiO2光催化降解甲苯的效率,其中Pt/TiO2的光催化活性最佳。循环伏安法(CV)、塔菲尔(Tafel)和Mott-Schottky电化学测试证明Pt的负载抑制光生电子和空穴的复合,提高载流子浓度,进而增强TiO2光催化活性。     

Synergistic photocatalytic degradation of pyridine using precious metal supported TiO2 with KBrO3

A series of precious metals catalysts （M/TiO/, M = Ru, Rh, Pd, Ag, Ir, Pt or Au） were prepared by a light deposition method and the synergistic photocatalytic degradations of pyridine （20 mg/L） under UV irradiation （365 nm） using M/TiO2 with electron capture agent KBrO3 have been investigated. The results show that KBrO3 has a greatly synergistic role on M/TiO2 and the photocatalytic activity of M/TiO2 is closely related to its work function. Ag could greatly enhance the activity of TiO2 due to the binding characteristics of pyridine on Ag. Under the conditions of 0.5 wt.% Ag loading, Ag/TiO2 concentration of 0.1 g/L, KlrO3 concentration of 10 mmol/L and reaction liquid pH value at 9, the pyridine can be degraded by 64% within 3 hr, doubled than TiO2 photocatalytic system. The degradation kinetics of pyridine follows first-order kinetics and k = 5.53 × 10-3 min^-1.     

钙钛矿LaMnO3负载贵金属在催化氧化碳烟中的作用

采用共沉淀法制备钙钛矿LaMnO₃,并用浸渍法在LaMnO₃上负载不同的贵金属得到系列催化剂.利用程序升温氧化反应对催化剂催化氧化碳烟的性能进行了测试.程序升温还原(H₂-TPR)、BET、XRD、SEM和FT-IR等表征手段对催化剂进行了表征.结果表明,当Pd的负载量在0.5%时,催化剂Pd/LaMnO₃的催化性能最好,和单独的LaMnO₃相比,最高燃烧速率温度降低了40℃.当负载量较小和较多时,碳烟起燃温度反而会比LaMnO₃高.在5种贵金属负载的催化剂中,其中Pd催化性能最好,依次为Au、Ru、Pt和 Rh.TPR测试表明贵金属的负载有助于钙钛矿中Mn⁴⁺的还原,对高温时Mn³⁺的还原作用不大.XRD衍射角向低角度出现了少许偏移,显示负载在表面的贵金属部分进入钙钛矿LaMnO₃的晶格结构中,使其晶粒增大;BET和SEM结果表明催化剂在反应后出现了轻微团聚现象.IR图谱显示反应前后,主要特征红外吸收带没有明显变化, 表明催化剂具有较好的结构稳定性.适量的贵金属在钙钛矿LaMnO₃上负载,能够有效地提高催化燃烧碳烟的活性.     

Au负载OMS-2催化剂的制备及其低温催化氧化性能

通过前掺杂法(QI),浸渍法(IM)和沉积-沉淀法(DP)3种方法制备了Au负载氧化锰八面体分子筛(OMS-2)Au/OMS-2催化剂,研究了制备方法和制备条件对其催化氧化CO活性的影响.采用X射线衍射(XRD)和BET比表面积测定等技术对所制样品进行表征.结果表明,沉积-沉淀法制备的Au/OMS-2-DP催化剂活性明显高于前掺杂法和浸渍法制备的催化剂,这与Au/OMS-2-DP催化剂比表面积较大和负载Au颗粒较小有关.制备条件(沉淀剂种类、制备溶液pH、Au负载量和催化剂焙烧温度)明显影响Au/OMS-2-DP催化剂的催化活性.对于各种不同的沉淀剂,以KOH为沉淀剂制备的催化剂活性最高,这可能与其无钝化作用,而且形成的Au颗粒较小有关;制备溶液的为最佳,当pH值过高或过低容易导致Au颗粒的聚集和Au沉淀量较少;XRD结果表明,当Au负载量为5wt%催化剂和催化剂焙烧为300℃时,所制备的催化剂颗粒最小,所得的催化剂活性最高.最佳条件制备的Au/OMS-2-DP催化剂活性较好,CO完全转化(100%)的温度为67℃.     

由贵金属取代的钙钛矿催化剂对碳烟的催化性能

用柠檬酸法制备了不同贵金属取代的钙钛矿LaCo0.96X0.04O3(X为Pt、Pd、Rh、Au、Ag)催化剂,用热重法测试了催化剂对碳烟的催化活性,采用程序升温还原法(H2-TPR)、X-射线衍射仪(XRD)、能量谱仪(EDS)和红外光谱(FTIR)对催化剂进行了测试.结果表明,催化剂LaCo0.96Ag0.04O3催化活性最高,起燃温度为449℃,远低于LaCoO3的504℃;各贵金属取代的钙钛矿LaCoO3的TPR还原峰变化各异;XRD特征峰的衍射角向高角度偏移,说明各贵金属进入了钙钛矿结构相;能谱图显示各贵金属进入钙钛矿相的量不同.     

Remove cooking fume using catalytic combustion over Pt/La-Al2O3

Five monolithic catalysts with low noble metal content were prepared by irnmerge method （Pt/γ=Al2O3, Pt/La-Al2O3, Pt/YSZ-AI203, Pt＋Pd/La-Al2O3 and Pd/La-Al2O3） and their activity measurements were carried out in a conventional fixed-bed flow reactor. The results show that La-Al2O3 can promote activity of the prepared catalysts and can decrease the complete conversion temperature of cooking fume. The Pt/La-Al2O3 catalyst has the highest activity and can be applied in wide range of gas hourly space velocity （GHSV）. Some characterizations （XRD, TPR） were carried out with the objective to explain differences in catalytic behaviors. The prepared catalyst showed a great potential for application.     

Pd/g-C3N4对水中2,4-二氯酚的催化加氢脱氯研究

分别采用光沉积法和浸渍法制备了载钯石墨相氮化碳催化剂(Pd/g-C3N4-PD和Pd/g-C3N4-IMP),并对其进行了电感耦合等离子体发射光谱(ICP-AES)、X射线衍射(XRD)、透射电镜(TEM)和Zeta电位的表征.结果表明,不同载钯量Pd/g-C3N4-PD的等电点均在pH 2.3左右;Pd/g-C3N4-PD表面Pd粒子分散均匀,且Pd粒径小于Pd/g-C3N4-IMP.分别将Pd/g-C3N4-PD和Pd/g-C3N4-IMP用于2,4-二氯酚的催化加氢脱氯研究,Pd/g-C3N4-PD的催化脱氯效果明显优于Pd/g-C3N4-IMP.低pH值利于2,4-二氯酚的催化加氢脱氯过程,但不利于保持催化剂的稳定性.     

CuO对贵金属/CeO2/Al2O3催化剂的作用

制备含少量贵金属Ｐｔ、Ｐｄ的不同Ｃｕ和Ｃｅ摩尔含量比（０：１０,１：９,２：８）的催化剂,实验条件十加入ＣｕＯ可以提高Ｐｔ催化剂的二效活性;加入Ｃｕ：Ｃｅ＝２：８的ＣｕＯ降低了Ｐｄ催化剂的顾效性能,然而Ｃｕ：Ｃｅ＝１：９时可以改善Ｐｄ催化剂的三效催化性能。通过结构分析,认为ＣｕＯ的存在可以提高ｄ催化剂的比表面积,ＰｄＯ的分散度。     

Low-temperature VOCs oxidation performance of Pt/zeolites catalysts with hierarchical pore structure

Different zeolites supported Pt catalysts with micro-mesoporous structure were prepared by organic base tetrapropylammonium hydroxide (TPAOH) treatment and their catalytic oxidation activity for various volatile organic compounds (VOCs) were evaluated. The results reveal that the synergistic effect between Pt nanoparticles and surface acid sites plays an important role in VOCs low-temperature removal. The small size and high dispersion of Pt nanoparticles on the surface of the zeolites would promote the catalytic oxidation of aromatics and alkanes over the Pt/zeolite catalysts, while strong acidity and abundant acid sites of catalysts are in favour of the oxidation of the VOCs containing N and O heteroatoms. In addition, it was found that Pt/ZSM-5 catalyst exhibits the highest oxidation activity for various VOCs low-temperature removal amongst all the catalysts due to the balance of both Pt dispersion and abundant acid sites in the catalyst. This comprehensive consideration should be very helpful when designing and preparing novel catalysts for the low-temperature removal of VOCs.     

Au/SnO_2/TiO_2催化氧化CO性能的研究

通过煅烧制备TiO2,用浸渍法负载SnO2,沉积沉淀法负载Au,制备不同SnO2含量的Au/SnO2/TiO2催化剂。采用BET、SEM、XRD等手段对催化剂样品进行表征并考察煅烧温度、SnO2的添加量等对Au/SnO2/TiO2催化剂催化CO氧化活性的影响。结果表明:Au/SnO2/TiO2催化活性比Au/TiO2明显提高;海绵钛在400℃煅烧后负载10%SnO2和1%的Au催化活性较好,在124℃左右能使气体中含量为2.94%的CO基本完全转化。     

Pt-Sn/Al2O3蜂窝催化剂催化氧化C6烃

采用等体积分浸法制备Pt-Sn/Al₂O₃蜂窝催化剂（Pt含量仅为0.06wt%）.运用X射线衍射（XRD）、透射电镜（TEM）等技术对催化剂理化性质进行表征,并选取4种代表性C₆烃（苯、环己酮、环己烷和正己烷）对催化剂性能进行评价.活性评价试验中,Pt/Sn比为3/1催化效果最佳.此时4种C₆烃转化率达到90%的温度（T₉₀）较Pt催化剂均降低约20℃,其原因在于Sn可将Pt分割为较小的团簇提高Pt分散度.寿命评价试验以环己烷为例同Pt-Sn蜂窝催化剂连续运行720h,催化活性无明显变化,其原因在于,Sn可有效抑制其粒径增长;Pt₃Sn合金降低表面对C₆烃的吸附,减少催化剂表面积炭.     

TiO2纳米膜光催化深度处理城市污水的实验研究

采用溶胶-凝胶方法制备光催化性能优良的TiO2纳米膜,应用X射线衍射仪分析了TiO2纳米膜的结构,探讨了铁离子和贵金属Ag、Pt掺杂对TiO2纳米膜光催化降解性能的影响,研究了TiO2纳米膜及掺杂改性TiO2纳米膜对生物二级处理系统出水中有机物光催化去除的性能。贵金属Ag、Pt掺杂提高了TiO2纳米膜光催化性能,而铁离子掺杂则降低了其催化性能。未掺杂的TiO2纳米膜使二级出水的COD下降8.9%,而贵金属Ag、Pt掺杂的TiO2纳米膜则使COD分别下降19.4%和22.3%。实验结果表明TiO2纳米膜有优良的光催化降解性能,TiO2纳米膜有广阔的应用前景。     

OMS-2负载Pt催化剂的制备及其催化氧化性能研究

采用前掺杂法、沉积-沉淀法和浸渍法制备了氧化锰八面体分子筛(OMS-2)负载Pt催化剂(Pt/OMS-2),对所制催化剂进行了结构和织构表征。并研究了不同制备方法和沉积-沉淀法中不同制备(Pt负载量和溶液的pH值)对Pt/OMS-2催化氧化CO性能的影响。结果表明,沉积-沉淀法制备的Pt/OMS-2-DP催化剂活性最好(T100=100℃)。这与Pt/OMS-2-DP催化剂中Pt颗粒大小及OMS-2载体与Pt之间存在强相互作用有关。Pt负载量明显影响Pt/OMS-2-DP催化剂的催化活性,3Pt/OMS-2-DP催化剂(Pt=3.0 wt%)催化活性最高,这是由于适当Pt负载量,Pt颗粒较小,并与载体OMS-2的相互作用较强,能较好地活化OMS-2晶格氧。pH值对Pt/OMS-2-DP催化剂催化性能影响较大,这与OMS-2的等电点和Pt在不同溶液中存在不同Pt配位体形式有关。     

ICP-AES测定电镀污泥中的金和钯

介绍了含贵金属电镀污泥的样品采集、制备和预处理方法,并对有关问题进行了讨论.研究了电感耦合等离子体-原子发射光谱(ICP-AES)直接测定电镀污泥中微量金、钯的分析方法.结果表明:在选定的最佳仪器工作条件下,金、钯的检出限分别为0.015和0.018 mg/L,加标回收率为94.0%～104.0%,相对标准偏差小于3%.该方法可用于电镀污泥中微量金、钯的测定      

Mo-modified Pd/Al2O3 catalysts for benzene catalytic combustion

Mo-modified Pd/Al2O3catalysts were prepared by an impregnation method and tested for the catalytic combustion of benzene. The catalysts were characterized by N2 isothermal adsorption, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, temperatureprogrammed desorption of NH3（NH3-TPD）, H2temperature-programmed reduction（H2-TPR）, and high-angle annular dark-field scanning transmission electron microscopy（HAADF-STEM）. The results showed that the addition of Mo effectively improved the activity and stability of the Pd/Al2O3catalyst by increasing the dispersion of Pd active components, changing the partial oxidation state of palladium and increasing the oxygen species concentration on the surface of catalyst. In the case of the Pd-Mo/Al2O3catalyst,benzene conversion of 90% was obtained at temperatures as low as 190°C, which was 45°C lower than that for similar performance with the Pd/Al2O3catalyst. Moreover, the 1.0% Pd-5% Mo/Al2O3catalyst was more active than the 2.0% Pd/Al2O3catalyst. It was concluded that Pd and Mo have a synergistic effect in benzene catalytic combustion.     

负载型纳米金催化剂对室内空气中甲醛的去除

采用沉积-沉淀法(deposition precipitation,简称DP法)和共沉淀法(coprecipitation,简称 CP法)制备了负载型纳米金催化荆Au/Fe2O3,催化剂中金含量(质量分数)小于1%.并以甲醛完全氧化反应作为研究的目标反应.这个反应可以有效地去除室内空气中的有害成分甲醛.通过催化活性的测试和XRD、TEM、TPR等技术对催化剂进行了表征.结果表明,两种方法制备的催化剂有各自的优势和特点,其中DP法制备的催化剂金含量(质量分数)只有0.67%的情况下,经过条件优化,甲醛完全转化温度为80℃,是一个较好的结果;而CP法制备的样品有较好的抗热性,可能有利于催化剂的使用寿命.因此,本工作为该类催化剂实用化提供了有价值的信息和依据.     

Conversion of the refractory ammonia and acetic acid in catalytic wet air oxidation of animal byproducts

Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) of slaughtered animal byproducts (ABPs) were investigated. Two step experiment was carried out consisting of a non-catalysedWAO run followed by a CWAO run at 170–275°C , 20 MPa, and reaction time 180 min. TheWAO (1st step) of sample (5 g/L total organic carbon (TOC)) yielded (82.0 4)% TOC removal and (78.4 13.2)% conversion of the initial organic-N into NH4 +-N. Four metal catalysts (Pd, Pt, Rh, Ru) supported over alumina have been tested in catalytic WAO (2nd step) at elevated pH to enhance ammonia conversion and organic matter removal, particularly acetic acid. It was found that the catalysts Ru, Pt, and Rh had significant e ects on the TOC removal (95.1%, 99.5% and 96.7%, respectively) and on the abatement of ammonia (93.4%, 96.7% and 96.3%, respectively) with high nitrogen selectivity. The catalyst Pd was found to have the less activity while Pt had the best performance. The X-Ray di raction analysis showed that the support of catalyst was not stable under the experimental conditions since it reacted with phosphate present in solution. Nitrite and nitrate ions were monitored during the oxidation reaction and it was concluded that CWAO of ammonia in real waste treatment framework was in good agreement with the results obtained from the literature for ideal solutions of ammonia.     

Enhanced photo--catalytic activity of gold ion and gold modified

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Synergistic effect of palladium and oxygen vacancies in the Pd/perovskite catalysts synthesized by the spc method

A series of oxygen-deficient perovskite-supported palladium catalysts were prepared by the “solid phase crystallization“(spc) ethod and investigated with XRD, TPR, TPD, TEM, XPS, BET analysis and CO oxidation. It was found that Pd/perovskite catalysts ynthesized by the spc method were more active for CO oxidation than the calcined LaCoo.95 Pdo.05 03, where Pd dispersed in the solid olution. H2-reducing treatment in the spc method could yield not only high-dispersed fine Pd particles on the perovskite surface but also xygen-deficient structure. In these perovskite-supported Pd catalysts, oxygen vacancies adsorbed, activated and supplied oxygen to the ctive Pd sites, where the oxidation occurred with adsorbed CO. The high activities were due to the cooperative action of Pd and oxygen acancies.     

Photocatalytic degradation of L-acid by TiO2 supported on the activated carbon

Introduction Aromatic sulfonic acid, which is produced in large amounts in chemical industry since the end of 19th century, has been widely applied in many industrial processes, including the various steps of procedure (Alonso and Barcelo, 2000). Naphthalene- sulfonic acids are of importance as dye intermediates and commonly used in the textile auxiliary industry employing many azo dyes and pigments. Among them, 1-naphthol-5-sulphonic acid (L-acid) is widely used in the printing as the raw ma…