Ce-Ti-O_x/CNTs复合粒子的制备及其对风化煤氧解的催化性能

以柠檬酸为螯合剂,以自制碳纳米管(CNTs)为载体,采用柠檬酸螯合沉积法制备了Ce-Ti-Ox/CNTs复合粒子,考察了柠檬酸的用量和乙二醇的添加对产物形貌的影响,采用TEM、XRD和FR-IR等手段对样品的形貌和晶相结构进行表征。结果表明,乙二醇的"桥接"作用有效地改善了负载效果及被负载的粒子均匀。探讨了复合金属氧化物的负载机理,并在此基础上研究了所得样品在风化煤硝酸氧解制备腐植酸中的催化性能,催化结果表明,Ce-Ti-Ox/CNTs复合粒子的催化性能明显优于单纯的CNTs、CeO2、TiO2、CeO2/CNTs以及TiO2/CNTs的催化性能,使腐殖酸的产率达到了65.43%。     

石墨烯/Ni/TiO_2/CNTs复合物的制备及其光催化性能

首先通过溶剂热法,在石墨烯表面负载掺杂镍的纳米二氧化钛膜,制备石墨烯/Ni/TiO2复合材料;然后以掺杂的镍为催化剂,采用化学气相沉积法,原位生长碳纳米管(CNTs),得到石墨烯/Ni/TiO2/CNTs复合材料。通过XRD、SEM、TEM、拉曼等方法对制备样品的晶型、微观形貌等进行了表征,考察了样品在紫外光及可见光下对甲基橙的光催化降解性能。结果表明:石墨烯和CNTs的加入使得Ni/TiO2、石墨烯/Ni/TiO2、石墨烯/Ni/TiO2/CNTs复合物的光催化活性依次提高,并且石墨烯/Ni/TiO2/CNTs复合物中石墨烯含量越多时,所得复合物的光催化降解性能越好。石墨烯含量最大的石墨烯/Ni/TiO2/CNTs样品,在紫外光下对甲基橙的降解率达到98%,在可见光下的光催化降解效率比掺镍TiO2提高了3.5倍。     

负载型Fe2O3/γ-Al2O3催化剂的制备及其对煤微波热解的催化活性

为实现低变质煤资源化的目标,在低变质煤微波热解的基础上采用超声浸渍-焙烧法制备负载型Fe2O3/γ-Al2O3催化剂,采用场发射扫描电镜(SEM)及X射线能谱(EDS)对催化剂进行表征,研究了其对煤微波热解过程中的催化效果及机理,考察焙烧时间、焙烧温度等因素对催化剂催化活性的影响,通过气-质联用(GC-MS)及煤气分析仪对焦油及气体组分和含量进行测定。结果表明,Fe2O3/γ-Al2O3催化剂的加入提高了煤微波热解制氢气及焦油产率,超声浸渍条件下400℃焙烧4h制备的产品催化活性最佳。     

钢渣负载TiO2光催化降解苯酚研究

以钢渣为载体,工业钛液为原料,采用溶胶-凝胶法制备钢渣负载TiO2光催化剂,通过SEM对该催化剂进行表征,以苯酚为目标物考察了钢渣负载TiO2光催化剂的催化性能。实验结果表明,该催化剂在紫外光照射下光催化性能较优,向100mL浓度为40mg/L的苯酚溶液中加入10g/L催化剂,苯酚的降解率可达78.3%。适当增加负载次数有助于提高光催化性能,当负载次数为3次时,苯酚的光催化降解率可达86.7%。     

基于Pt/CNTs催化剂的燃料电池Pt/Buckypaper催化层的制备与表征

为了提高质子交换膜燃料电池催化剂中贵金属的利用率,以碳纳米管(CNTs)负载Pt为催化剂,设计制备了具有催化剂梯度分布结构的Pt/buckypaper催化层。利用扫描电子显微镜等多种表征手段,观察与分析了催化剂和催化层的结构及Pt含量分布,并考察了它们的电化学性能。结果表明,Pt/CNTs催化剂中Pt颗粒在超声混酸氧化处理过的CNTs表面上分布均匀,平均直径为2.4nm。其电化学活性表面积(ECSA)接近于商用Pt/C催化剂的值,比质量活性(MA)则远高于商用催化剂,且具备更为优异的电化学循环稳定性。利用这种催化剂制备的Pt/buckypaper催化层保持着较大的ECSA,表明其中的Pt颗粒具有较高的利用率,体现了这种新颖结构的独特优势。     

TiO2／海泡石催化剂的光催化降解性能

以钛酸四丁酯为前驱体,采用水解．沉淀法制备纳米TiO2,再将其负载于海泡石上制得TiO2/海泡石催化剂,用X射线衍射和扫描电子显微镜对载体催化剂的形貌及晶型进行了分析．以紫外光为光源,在水溶液中以环境激素邻苯二甲酸二乙酯（DEP）为降解底物进行光催化性能的研究．结果表明：催化剂的用量和TiO2的负载量对光催化降解速率都有影响．其中TiO2/海泡石催化剂的用量起主要作用,更能影响其光催化速度及DEP的降解．当催化剂用量为4g/L、TiO2负载量为30％时,TiO2/海泡石催化剂的催化效果较好．     

CWPO处理含酚废水催化材料与反应机理研究进展

酚类污染物是常见的有机污染物之一,含酚废水处理难度大、毒性强,对自然环境与人类健康具有严重危害。催化湿式过氧化氢氧化技术(CWPO)以H₂O₂为氧化剂,利用催化剂催化产生·OH强氧化性自由基,可去除水中难降解有机污染物。介绍了CWPO非负载与负载型催化剂在含酚废水中的应用情况,负载型催化剂更具应用前景。利用密度泛函理论(DFT)分析了苯酚、间甲酚污染物主要降解途径,降解含酚废水是通过体系中·OH逐步改变苯环稳定结构形成苯醌类中间体,该中间体C-C断裂开环形成短链羧酸,最终完全矿化为CO₂和H₂O。未来可从制备稳定环保催化剂、分析实际废水降解机制方面展开研究,以发挥CWPO在含酚废水中的应用潜力。     

Ni／CNTs及钙改性Ni／CNTs催化剂在二氧化碳甲烷化反应中性能

分别以碳纳米管（CNTs）和活性氧化铝（Al2O3）为载体,通过浸渍法制备了负载型镍基催化剂和钙改性的镍基催化剂,用二氧化碳甲炕化反应评价其催化性能,通过X射线衍射（XRD）、程序升温还原（H2-TPR）、程序升温脱附（H2-TPD）和氮气等温吸附脱附等手段对催化剂进行表征,结果表明,Ni／CNTs催化剂中的镍物种比Ni／Al2O3中的镍物种容易还原,同时钙改性Ni／CNTs催化剂更能促进镍物种的还原,添加钙可以促进CNTs载体催化剂的分散度,这些特性能提高钙改性Ni／CNTs催化剂的催化活性和稳定性。     

CoMoN_x/CNTs催化剂氯代硝基苯选择性催化加氢反应性能

采用等体积浸渍法结合程序升温还原技术制备出一系列负载型过渡金属氮化物催化剂,并利用XRD、BET、TG-DSC等手段对催化剂进行表征。将此催化剂用于邻氯硝基苯液相催化加氢。结果表明,单组分MoN/CNTs催化剂的活性较低,氯代硝基苯转化率为57.5%,双组份CoMoN_x/CNTs的活性较高,氯代硝基苯转化率为89.8%,添加了稀土La后CoMoN_x/CNTs催化剂活性改善不明显,但对o-CAN选择性达到了99.3%。     

煤渣基二氧化钛复合材料制备及其光催化性能研究

采用微波辅助条件下的溶胶-凝胶法制备了煤渣负载纳米TiO_2光催化剂。X射线衍射仪、扫描电镜表征结果表明,所负载的TiO_2为锐钛矿型,平均粒径12nm。以亚甲基蓝为目标降解物,着重考察了不同煤渣含量、烧结温度、微波时间、微波功率对其催化性能影响结果表明,煤渣含量32.49%,微波时间为5min,微波功率为400 W,马沸炉温度为400℃时制备的催化剂,催化亚甲基蓝光TiO_2/煤渣复合材料降解效果最好。在搅拌条件下该催化剂催化的光降解反应符合一级动力学方程。     

Catalytic combustion of ethyl acetate on supported copper oxide catalysts

Total oxidation of ethyl acetate on supported copper oxide catalysts was investigated. The catalysts have been prepared by wet impregnation method and characterized by XRD, TEM and XPS. Among the catalysts with the supports of TiO2, CeO2/TiO2 and CeO2-ZrO2/TiO2, CeO2-ZrO2 solid solutions doped TiO2 supported catalyst gives the highest catalytic activity. Catalyst with the composition of 5 wt.% CuO/10 wt.% CeO2-ZrO2-TiO2 shows the total oxidation of ethyl acetate at about 270 degrees C with the 100% CO2 selectivity. The characterization studies of supported copper oxide catalysts showed that the highly dispersed CuO is one of the active phase which contacts intimately with the support, the action of the interface between the components was not be ignored.     

稀土元素镧与铈对VOx／TiO2催化降解氯苯性能的影响

采用等体积浸渍法分别制备了不同稀土元素@阑或铈）添加量的VOx／TiO催化剂,通过XRD、EDS和TPR对样品进行表征,考察了它们催化燃烧氯苯的活性,结果表明,不同镧或铈添加量的催化剂样品仍保持TiO2税钛矿晶相。当LaOx与VOx的摩尔比为1：5时,会出现镧钒氧物种或镧钛氧物种的晶相;当CeOx与VOx的摩尔比为1．5时,会出现CeOx方铈矿萤石结构的晶相;镧和铈的添加会提高活性物种VOx在催化剂表面的含量和分数}生。当CeOx与VOx的摩尔比为1：13．7时,活性组分VOx绝大部分分布在载体表面;镧对于催化剂的氧化性能没有影响,而铈能提高催化剂的氧化性;适量镧或铈的添加对于VO／TiO2催化剂催化降解氯苯有促进作用。锏的添加对于催化剂催化活性的促进作用与催化剂表面活性物VOx含量有关,而铈的添加对催化剂催化活性的提高作用除此原因外,还与催化剂氧化洼的提高有关。     

Growth of carbon nanotubes over Fe-Co and Ni-Co catalysts supported on different phases of TiO2 substrate by thermal CVD

The aim of this work is to examine the properties of CNTs formed on Fe-Co and Ni-Co bimetallic catalysts supported on different phases of TiO₂ (anatase and rutile) by wet impregnation method. The CNTs are grown from decomposition of acetylene via Thermal CVD at 700°C using the prepared catalysts. The nanomaterials were characterized by XRD, Xmap, BET, FESEM, TEM, and Raman spectroscopy. It was found that the catalyst samples supported on rutile TiO₂ have higher specific surface area, smaller catalytic nanoparticles with denser distribution and very more activity compared to anatase ones. Consequently, the CNTs nucleated from nanoparticles supported on rutile TiO₂ possess higher density, smaller average diameters and narrower diameter distribution compared to grown CNTs on anatase samples. Moreover, it was observed that the Fe-Co bimetallic catalysts regardless of TiO₂ support phase, possesses more catalytic activity and higher average growth rate of CNTs in compare with Ni-Co catalysts.     

Preparation of mesoporous titania solid superacid and its catalytic property

Mesoporous titania (TiO(2)) was synthesized by hydrothermal method using cetyltrimethyl ammonium bromide (CTAB) as a template and using anhydrous ethanol and tetra-n-butyl titanate (TBOT) as raw materials. Mesoporous titania solid superacid and nanosized titania solid superacid catalysts were prepared by wet impregnation method. The structure and property of as-prepared samples were characterized by means of XRD, FT-IR and N(2) physical adsorption. The esterification of salicylic acid with isoamyl alcohol and the condensation of cyclohexanone with ethylene were used as model reactions to test the catalytic activities of the catalysts. On the other hand, the comparison of catalytic activities of the prepared solid superacid catalysts and the conventional liquid acid H(2)SO(4) was also carried out under the same experimental conditions. The results show that the catalytic activities of the prepared solid superacid catalysts were higher than that of the conventional liquid acid H(2)SO(4), and that the catalytic activity of mesoporous TiO(2) solid superacid is the highest among the three catalysts. Mesoporous TiO(2) solid superacid is a good catalyst for the synthesis of isoamyl salicylate or cyclohexanone ethylene ketal.     

A comparative study of catalytic partial oxidation of methane over CeO2 supported metallic catalysts

In the present study, the catalytic partial oxidation of methane (CPOM) over various active metals supported on CeO2 (M/CeO2, M = Ir, Ni, Pd, Pt, Rh and Ru) has been investigated. The catalysts were characterized by X-ray diffraction (XRD), BET surface area, H2-temperature programmed reduction (H2-TPR), CO chemisorption and transmission electron microscope (TEM) analysis. Ir/CeO2 catalysts showed higher BET surface area, higher metal dispersion, small active metal nano-particles (approximately 3 nm) than compared to other M/CeO2 catalysts. The catalytic tests were carried out in a fixed R(mix) ratio of 2 (CH4/O2) in a fixed-bed reactor, operating isothermally at atmospheric pressure. From time-on-stream analysis at 700 degrees C for 12 h, a high and stable catalytic activity has been observed for Ir/CeO2 catalysts. TEM analysis of the spent catalysts showed that the decrease in the catalytic activity of Ni/CeO2 and Pd/CeO2 catalysts is due to carbon formation whereas no carbon formation has been observed for Ir/CeO2 catalysts.     

Lamellar Fe/Al2O3 catalyst for high-yield production of multi-walled carbon nanotubes bundles

The lamellar Fe/Al₂O₃ catalysts were prepared by sol-gel method, and then with these prepared catalysts, carbon nanotubes (CNTs) were synthesized by catalytic chemical vapor deposition (CCVD) method using C₂H₂ as precursor. The as-prepared CNTs and Fe/Al₂O₃ catalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and Raman spectrum. The results proved that the as-prepared CNTs actually existed in bundles. And the growth of CNTs bundles should be attributed to the lamellar catalysts, which supported the bottom growth mechanism of CNTs. The transition metal of Mo was not introduced in catalysts to produce CNTs bundles, which was different with others’ results.     

Electrochemical characterization of nano-sized Pd-based catalysts as cathode materials in direct methanol fuel cells

To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd-TiO2) catalysts which the Pd and TiO2 nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO2 as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO2 on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd-TiO2/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd-TiO2 catalysts were strongly influenced by the TiO2 content. In the single cell test, the Pd-TiO2 catalysts showed very comparable performance to the Pt catalyst.     

富氢气氛中CO选择性氧化CuO/CeO2催化剂的研究

选择负载型铜催化剂为研究对象,以富氢条件下研究CO选择性氧化反应为导向,考察了反应气氛、焙烧温度、CuO含量及Al2O3掺杂对CuO/CeO2催化剂的CO选择性氧化催化性能的影响,并采用TEM表征技术探讨结构与性能的关系。     

Effect of preparation methods on the structure and catalytic performance of TiO(2)/AC photocatalysts

Activated carbon (AC)-supported TiO(2) catalysts were prepared by sol-gel and metal organic chemical vapor deposition (MOCVD) in order to investigate effect of preparation methods on the structure and catalytic performance of TiO(2)/AC catalysts. It was found that both methods yield "egg-shell" TiO(2)/AC catalysts, that is to say, the TiO(2) coatings were mainly on the surface of AC supports. The TiO(2) coating by sol-gel was only coated on the external surface of AC. In contrast, TiO(2) by MOCVD was deposited on the surface of AC through the heterogeneous reaction, forming a TiO(2)+AC hybrid film (about 3 microm) as evidenced by SEM and N(2) adsorption tests. The hybrid TiO(2)+AC film could capture the intermediates produced during the degradation of the target pollutant resulting in efficient mineralization. The TiO(2)/AC catalysts by MOCVD exhibited a Ti-O-C bond, which correlated with the good stability of TiO(2) as observed on the corresponding samples. These results indicate MOCVD is a better choice for the preparation of TiO(2)/AC catalysts.