不同形貌纳米CuO催化氧化风化煤制取腐植酸的研究

分别采用超声辅助热沉淀法和水热法制备了片状纳米CuO(Cu O-s)和棒状纳米CuO(CuO-r)催化剂。以X-射线衍射仪(XRD)、透射电镜(TEM)手段对产物进行了表征。考察了两种形貌的纳米CuO催化剂在碱性条件下催化氧化风化煤制取腐植酸的活性。利用元素分析、红外光谱和E_4/E_6值分析研究了腐植酸产物的结构和性质,讨论了两种形貌的纳米CuO催化氧化对腐植酸产率、元素组成和官能团种类的影响。结果表明,两种形貌的纳米CuO均可显著提高腐植酸的产率,以CuO-r催化活性最高。与仅加入H_2O_2相比,加入CuO-r催化剂,腐植酸产率可提高16.36%,并且催化氧化所得腐植酸与天然腐植酸具有相似的元素组成和结构特征。     

催化湿式氧化法处理含酚废水

进行了CuO/Al2O3、CuO MnO2/Al2O3、CuO K2O/Al2O3、CuO/CeO2催化剂在160℃和1.6MPa的氧气压力条件下,催化氧化法处理含酚废水的实验,结果表明催化剂CuO/CeO2具有最高的催化活性,COD为3000mg/L左右含酚废水,反应50min后降解97%。并测定了在135～165℃和1.6MPa氧气压力下,加入催化剂CuO/Al2O3氧化含酚废水的COD与时间的的关系,求取了反应的动力学方程。初步探讨了氧分压和溶液的pH对催化氧化反应速率的影响。     

催化氧化法合成环己酮技术研究进展

介绍了以环己烷为原料催化氧化合成环己酮的主要方法,分析了环己烷氧化采用的主要催化剂。环己烷硼酸催化氧化法和钴盐催化氧化法存在环己烷转化率低及结渣现象;分子筛催化氧化法、金属氧化物以及金属络合物仿生催化氧化法可提高环己烷转化率及醇酮选择性;金属络合物仿生催化氧化法具有良好的开发应用前景。     

非光气法催化合成碳酸二苯酯研究进展

综述了近年来酯交换法、苯酚氧化羰化法、草酸二甲酯和苯酚交换、脱羰法和尿素酚解法4种非光气法催化合成碳酸二苯酯（DPC）的研究进展,包括每种合成法所使用的催化剂、反应条件、反应物的转化率和产物的收率,指出了每种合成法的优缺点,并从原料来源的难易、催化剂制备的成本、产物的收率、生产工艺的复杂性、能耗等方面进行分析比较,指出选用酯交换法和尿素酚解法生产碳酸二苯酯较为有利,这两种合成法可能是未来研究的重点。     

CuO催化臭氧氧化深度处理垃圾渗滤液的研究

采用粉末CuO作为催化剂,对生化处理后的低浓度垃圾渗滤液进行催化臭氧氧化深度处理.探讨了反应时间、催化剂投量、温度、pH、起始CODCr及氯离子含量对渗滤液有机污染物去除的影响.在进水COD.为350 mg/L,色度为1 000 PCU的条件下,氧化反应120 min后CODCr、TOC及UV254的去除率能够达到70%～80%,色度的去除率几乎达到100%.试验结果得出,在常温条件下,CuO催化臭氧氧化法深度处理低浓度垃圾渗滤液的最佳反应时间为120 min,CuO最佳投量为0.5 s/L,反应最佳pH为6～8.     

CuO含量对yCuO/CuxCe1-xOδ催化剂脱除痕量CO性能影响

采用柠檬酸络合-浸渍相结合的方法制备yCuO/CuxCe1-xOδ催化剂,通过XRD、BET、H2-TPR等手段研究了载体掺杂CuO含量（x值）、表面负载CuO含量（y值）对yCuO/CuxCe1-xOδ催化剂催化氧化CO性能的影响。结果表明,载体中掺杂的CuO能与CeO2产生协同作用,有利于负载的CuO在载体表面均匀分散,促进氧化-还原性能的提高,提升CO催化氧化活性。采用正交试验法,经DPS（Data Process System）软件对CuO含量进行逐步回归优化,优化得到16.40 %CuO/Cu0.05Ce0.95Oδ催化剂具有较优的催化氧化CO性能,该催化剂在50 ℃、3.0 MPa的工况条件下,可将液相丙烯中微量CO从1.0 × 10-5（φ,体积分数）降至3.0 × 10-8（φ）,达到聚合级烯烃对CO脱除深度的要求,连续反应1400 min,稳定性良好。     

对氯甲苯催化氧化制备对氯苯甲醛的研究进展

对氯苯甲醛是一种广泛用于医药、农药和染料的精细化工中间体,发展其绿色合成工艺极具挑战性和重大意义。本文较为系统地综述了催化氧化对氯甲苯为对氯苯甲醛的制备方法,重点阐述了H₂O₂氧化法、空气/氧气氧化法、电解氧化法和仿生催化氧化法的工艺条件,比较了间接电氧化合成方法中的各种金属媒质,讨论了各种制备方法的优缺点,分析了其相应的合成方法在工业开发上的可行性及存在的问题。此外,简要介绍了利用光催化法选择性氧化对氯甲苯合成对氯苯甲醛的方法。通过对几种合成方法的比较,指出以H₂O₂和分子氧为氧化剂液相催化氧化对氯甲苯来合成对氯苯甲醛是较为经济、环保的合成方法,电解氧化法和仿生催化氧化法将为对氯苯甲醛制备提供另一条新型技术途径。     

碳酸二乙酯的制备工艺研究进展

碳酸二乙酯是重要的基础原料和绿色溶剂,分子中含有乙基、乙氧基、羰基和羰乙氧基,易于碳酰化、烷基化和羰酰化,在合成中间体、溶剂、能源动力和功能材料等方面的应用进展迅速。目前,碳酸二乙酯的制备方法主要为酯交换法、乙醇氧化羰基化法、尿素醇解法,研究重点主要集中在合成路径的选择、催化剂的选择性制备与催化合成、纯化方法的改进、工...     

组分含量对MnO_2-CuO/Y常温催化臭氧氧化甲苯性能的影响

采用等体积浸渍法制备MnO_2-CuO/Y催化剂,考察组分质量分数对常温催化臭氧氧化甲苯性能的影响。利用X射线衍射、N2吸附-脱附、氢气程序升温还原、甲苯吸附等分析方法对催化剂结构进行表征,以甲苯转化率维持在95%以上的时间(t95)为指标对催化性能进行评价。结果表明,当活性组分Mn O_2和CuO总负载量为10%且Mn O_2与CuO质量比为3∶2时,6%MnO_2-4%CuO/Y催化剂具有相对较高的比表面积和孔容积及较好的甲苯吸附性能,Mn O_2和CuO之间存在相互作用,形成固溶体,促进氧化还原性能的提高。因此,在常温催化臭氧氧化甲苯反应中,6%MnO2-4%CuO/Y催化剂表现出较高的反应活性,t95为260 min,COx选择性为85. 4%,CO_2与CO摩尔比为5. 36。     

CuO-ZnO-ZrO_2催化剂的还原性能及其低温CO催化氧化性能

采用共沉淀法制备得到CuO-ZnO-ZrO2催化剂及对比样品CuO-ZnO,通过XRD、BET、XPS、H2-TIR、H2-TPR等表征,考察了ZrO2的添加对CuO-ZnO-ZrO2催化剂的还原性能及其CO催化氧化性能的影响。与CuO-ZnO相比较,CuO-ZnO-ZrO2催化剂的比表面积增大、CuO和ZnO粒子的平均粒径减小、表面Cu粒子含量增多、还原性能得到显著提高,表明ZrO2的添加有利于提高CuO分散度,存在更多与ZnO相互作用的CuO微粒。TPR的还原动力学研究进一步证实了ZrO2对CuO还原性能的促进作用。在CO催化氧化反应中,CuO-ZnO-ZrO2样品的催化活性最高,并且还原温度对该催化剂的CO催化氧化性能影响显著,在160℃还原活化的催化剂具有77.3%的还原度,表现出较优的CO催化氧化性能。在50℃、3 MPa的反应条件下,CuO-ZnO-ZrO2催化剂可将液相丙烯中体积分数1.0×10-5的CO脱除低至2×10-8,连续反应1 500 min,稳定性能良好。     

CO oxidation over CuO catalysts prepared with different precipitants

CuO catalysts, prepared by the precipitation method using different precipitants such as ammonium hydroxide, sodium hydroxide, sodium carbonate and sodium hydrogen carbonate were applied to CO oxidation. Among the catalysts studied, CuO synthesized with sodium hydrogen carbonate showed the highest activity for CO oxidation. With the water vapor present in the feed gas, the catalytic activity decreased considerably due to reduction in the number of active sites by competitive adsorption between water vapor and CO. The H₂-TPR and CO-TPD results showed that existing Na⁺ cations and HCO ₃ ^? and CO_3/2? anions on the CuO surface could weaken the copper-oxygen bond strength and accelerate the mobility of oxygen on the surface or lattice. Finally, the morphology of the CuO crystals was dependent on the precipitants, and the introduction of Na⁺ cations and various anions resulted in the formation of smaller crystals.     

High catalytic performance of CuO nanocrystals with largest defects

To improve the calalytic performance of CuO, nanometer-sized CuO particles were prepared with ultrafiltration surface contact method (UMSCM). X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the crystal structure and morphology of the particles made with UMSCM, hydrothermal method, grounding method as well as a commercial one. SEM results illustrate that UMSCM prepared CuO particles mainly show the form of orthorhombic sliced crystals with the largest amounts of defects compared to CuO particles made by the other three methods. In the oxidation of cumene, CuO prepared with UMSCM also shows better catalytic performance than the other three particles, which can be ascribed to its smaller particle sizes and larger defects so as to accelerate the surface adsorption rate of O2 molecules and the diffusion of ions and atoms, thus improving the catalytic activity.     

Morphology-controlled synthesis of CuO nano- and microparticles using microwave irradiation

Microwave irradiation was used to obtain a variety of CuO crystal morphologies, including leaf-like, dandelion-like, and hollow structures. The morphology of the CuO crystals was controlled by varying the alkali source (NaOH, hexamethylenetetramine, ammonia, or urea) and heating at 95 °C for 1 hr. The X-ray diffraction patterns of as-prepared CuO crystals were consistent with high quality crystals with a monoclinic crystal structure. Field emission scanning electron microscopy (FE-SEM) and tunneling electron microscopy (TEM) images of CuO crystals revealed that the leaf-like CuO crystals had an average length of 950 nm and width of 450 nm, the small leaf-like CuO crystals had an average length of 450 nm and width of 200 nm, the dandelion-like CuO structures had an average diameter of 2 m, and the hollow CuO structures had an average diameter 2 m. Possible mechanisms for structure formation during the shape-selective CuO synthesis were proposed based on these results.     

Cooperative effect between copper species and oxygen vacancy in Ce0.7−xZrxCu0.3O2 catalysts for carbon monoxide oxidation

The effects of Zr doping on the existence of Cu and the catalytic performance of Ce_0.7−xZr_xCu_0.3O₂ for CO oxidation were investigated. The characterization results showed that all samples have a cubic structure, and a small amount of Zr doping facilitates Cu²⁺ ions entering the CeO₂ lattice, but excessive Zr doping leads to the formation of surface CuO crystals again. Thus, the number of oxygen vacancies caused by the Cu²⁺ entering the lattice (e.g., Cu²⁺–□–Ce⁴⁺; □: oxygen vacancy), and the amount of reducible copper species caused by CuO crystals, varies with the Zr doping. Catalytic CO oxidation tests indicated that the oxygen vacancy and the reducible copper species were the adsorption and activation sites of O₂ and CO, respectively, and the cooperative effects between them accounted for the high CO oxidation activity. Thus, the samples x = 0.1 and 0.3, which possessed the most oxygen vacancy or reducible copper species, showed the best activity for CO oxidation, with full CO conversion obtained at 110 °C. The catalyst is also stable and has good resistance to water during the reaction.     

CuO/ZrO_2催化剂的催化性能研究

研究了粉体性能、Cu O负载量及灼烧温度对 Cu O/Zr O2 催化剂 CO氧化性能的影响 .结果表明 ,催化剂的活性随氧化铜的负载量的增加而增加 ,较低比表面积的 Zr O2 载体更容易制备高活性的催化剂 .实验还发现 ,Cu O/Zr O2 催化剂的活性与载体单位表面 Cu O的负载量相关 ,Cu O的负载量超过载体分散容量为 75% ,是制备高活性催化剂的重要条件 .     

CuO／ZrO2催化剂的催化性能研究

研究了粉体性能、CuO负载量及灼烧温度对CuO／ZrO2催化剂CO氧化性能的影响．结果表明,催化剂的活性随氧化铜的负载量的增加而增加,较低比表面积的ZrO2载体更容易制备高活性的催化剂,实验还发现,CuO／ZrO2催化剂的活性与载体单位表面CuO的负载量相关,CuO的负载量超过载体分散容量为75％,是制备高活性催化剂的重要条件．     

用热氧化法在微米丝上制备CuO纳米线

采用电镀和热氧化相结合的方法,在直径为30 ?m的丝上成功制备了直径为50～80 nm、长度在几个至十几个微米的CuO纳米线,并研究了温度和热氧化时间对其生长情况的影响。实验结果表明,随着热氧化时间延长,纳米线长度增加,保温4 h后均匀性也得到较好保证。热氧化温度在450～500 ℃内CuO纳米线可以较好生长。在500 ℃下保温4 h后,自然冷却至室温,沿着微米丝表面垂直生长成均一排列的CuO纳米线阵列。     

Fabrication,characterization, and kinetic study of vertical single-crystalline CuO nanowires on Si substrates

We report here on the first study of the growth kinetics of high-yield, vertical CuO nanowires on silicon substrates produced by the process of thermal oxidation. The length of the CuO nanowires could be tuned from several to tens of micrometers by adjusting the oxidation temperature and time. The grown CuO nanowires were determined to be single-crystalline with different axial crystallographic orientations. After a series of scanning electron microscopy examinations, the average length of CuO nanowires produced at each temperature was found to follow a parabolic relationship with the oxidation time. The parabolic growth rate at different oxidation temperatures was measured. The activation energy for the growth of CuO nanowires calculated from an Arrhenius plot was found to be about 174.2 kJ/mole. In addition, the current-voltage characterization indicated that the sample with high-density CuO nanowires exhibited ohmic behavior, and its resistance was found to significantly decrease with increasing environmental temperature. The result can be attributed to an increase in the number of carriers at higher temperatures.     

基于CuO/GO纳米复合材料的电化学无酶葡萄糖传感器的研究

通过水热法合成了CuO/GO纳米复合材料,对其晶体结构和形貌进行了表征,并用于构建无酶葡萄糖传感器。CuO/GO能催化葡萄糖的直接氧化。传感器的灵敏度为5.74μAmM-1,检出限为6.14×10-7 mol·L-1。     

糠醛的水解制备和应用研究进展

糠醛是由可再生的生物质为原料转化得到的高价值化工产品，具有广阔的应用前景。本文综述了近年来生物质催化水解制备糠醛的研究进展，同时总结了糠醛衍生产品的制备和应用。在对半纤维素水解产糖反应和木糖脱水反应进行机理分析的基础上，从反应原料、溶剂体系、催化剂和分离方法等方面归纳总结了生物质催化水解制备糠醛的最新研究进展，并提出当前生物质制备糠醛方法中存在的问题和应对方案。在此基础上，分析了糠醛经氢化、胺化、氧化、缩醛化、聚合等反应获得高价值衍生产品的研究进展。提出要实现糠醛绿色高效的生产和应用，应着力设计低成本、低能耗、低污染且高效率的催化反应体系，同时推进重要糠醛衍生产品的综合高效利用。