ZnO在CuO基甲醇合成催化剂还原过程中的作用

用一步并流共沉淀法制备了一系列具有不同组成的ＣｙＯ基样品，并测试了它们在合成甲醇反应中的活性。利用ＴＧ－ＤＴＧ手段，对各ＣｕＯ基样品的还原过程进行了考察，结果表明，ＺｎＯ组分对催化剂ＣｕＯ－ＺｎＯ－Ａｌ２Ｏ３的还原行为有重要影响。     

CO／H2合成甲醇CuO—ZnO—ZrO2催化剂的研究

通过活性测定，ＸＲＤ、ＴＧ－ＤＴＡ表征，考察了共沉淀法制备的铜锌锆合成甲醇催化剂中ＺｒＯ２对物相结构、催化活性及热稳定性的影响。结果表明，ＺｒＯ２能显著提高ＣＯ／Ｈ２合成甲醇的催化活性和热稳定性。催化剂母体、氧化态和还原态的物相并未发生变化，仍分别为：Ｃｕ２（ＯＨ）３ＮＯ３，（Ｃｕ，Ｚｎ）５（ＣＯ３）２（ＯＨ）６，（Ｃｕ，Ｚｎ）２ＣＯ３（ＯＨ）２，Ｚｎ５（ＣＯ３）２（ＯＨ）６；ＣｕＯ、ＺｎＯ；Ｃｕ     

预处理条件对用于CO_2加氢的超细CuO－ZnO－SiO_2催化剂性能的影响

采用ＸＲＤ、ＢＥＴ、ＴＰＲ手段，研究了焙烧和还原温度对超细ＣｕＯ－ＺｎＯ－ＳｉＯ２催化剂的性质及其ＣＯ２加氢反应催化活性的影响．胶体在５７３－７７３Ｋ范围内焙烧生成ＣｕＯ、Ｃｕ２Ｏ、ＺｎＯ晶相，随着焙烧温度继续升高，ＣｕＯ和ＺｎＯ晶粒逐渐变大，但催化剂的比表面积和孔容变化很小．在９７３Ｋ焙烧后出现Ｚｎ２ＳｉＯ４晶相，使催化剂比表积和孔容变小，导致催化剂活性降低．焙烧温度对催化剂活性的影响大于对ＣＯ２加氢产物分布的影响．在５４８－６４８Ｋ范围内，催化剂还原温度对其催化活性影响不大．７０３Ｋ高温还原后，可能由于Ｃｕ０晶粒的出现，使得催化剂的活性下降．ＴＰＲ研究结果进一步表明，焙烧温度影响ＣｕＯ同ＺｎＯ、ＳｉＯ２之间的相互作用和催化剂的还原行为．     

二氧化碳加氢合成甲醇铜基催化剂表面组成的研究

本文分别采用ＸＲＤ、ＥＳＲ、ＸＰＳ和ＸＡＥＳ等技术对于二氧化碳加氢低压合成甲醇用ＣｕＯ，ＣｕＯ－ＺｎＯ，ＣｕＯ－ＺｎＯ－Ａｌ＿２Ｏ＿３，ＣｕＯ－ＺｎＯ－ＺｒＯ＿２催化剂在不同条件下表面Ｃｕ、Ｚｎ、Ａｌ、Ｚｒ的存在价态进行了深入分析。实验发现催化剂在还原前Ｃｕ以Ｃｕ￣２＋存在，在还原后和反应状态下以Ｃｕ￣０存在；Ｚｎ在还原后和反应状态下有部分被还原为Ｚｎ￣（２－δ）（０＜δ＜２），Ｚｒ和Ａｌ仍保持其还原前价态。催化剂的表面化学组成为：Ｃｕ￣０／Ｚｎ（２－δ）￣＋／Ｚｒ￣４＋／Ａｌ￣３＋／Ｏ￣２－。     

预处理条件对用于CO2加氢的超细CuO—ZnO—SiO2催化剂性能的影响

采用ＸＲＤ、ＢＥＴ、ＴＰＲ手段，研究了焙烧还原温度对超细ＣｕＯ－ＺｎＯ－ＳｉＯ２催化剂的性质及其ＣＯ２加氢反应催化活性的影响，胶体在５７３－７７３Ｋ范围内焙烧生成ＣｕＯ、ＣＵ２Ｏ、ＺｎＯ晶相，随着焙烧温度继续升高，ＣｕＯ和ＺｎＯ晶粒逐渐变大，但催化剂的比表面积和孔容变化不不，在９７３Ｋ焙烧后出现Ｚｎ２ＳｉＯ４晶相，使催化剂比表积和孔容积变小，导致催化剂活性降低，焙地催化剂活性的影响在于对ＣＯ２加氢     

助剂对超细CuO－ZnO－SiO_2催化剂性质和CO_2加氢反应性能的影响

研究了９种助剂对用于ＣＯ２加氢反应的超细ＣｕＯ－ＺｎＯ－ＳｉＯ２催化剂性能的影响，并进行了ＸＲＤ和ＴＰＲ表征．结果表明，助剂影响超细催化剂的性质和催化性能，ＴｉＯ２、ＣｅＯ２、ＭｇＯ和Ｌａ２Ｏ３是ＣＯ２加氢合成甲醇的超细ＣｕＯ－ＺｎＯ－ＳｉＯ２催化剂体系的优良助剂．在含有不同助剂的ＣｕＯ－ＺｎＯ－ＳｉＯ２催化剂体系内存在ＣｕＯ和ＺｎＯ晶相，但除ＣｅＯ２以外，其它的助剂都可能以微晶或无定型的形式存在．ＴＰＲ研究表明，添加的助剂除ＣｅＯ２以外，都使超细ＣｕＯ－ＺｎＯ－ＳｉＯ２催化剂的还原温度提高，而且助剂对ＣｕＯ－ＺｎＯ－ＳｉＯ２催化剂活性的影响，按照助剂对ＣｕＯ－ＺｎＯ－ＳｉＯ２催化剂还原温度的影响进行了探讨     

CO／H_2合成甲醇CuO－ZnO－ZrO_2催化剂的研究

通过活性测定，ＸＲＤ、ＴＧ－ＤＴＡ表征，考察了共沉淀法制备的铜锌锆合成甲醇催化剂中ＺｒＯ＿２对物相结构、催化活性及热稳定性的影响。结果表明，ＺｒＯ＿２能显著提高ＣＯ／Ｈ＿２合成甲醇的催化活性和热稳定性。催化剂母体、氧化态和还原态的物相并未发生变化，仍分别为：Ｃｕ＿２（ＯＨ）＿３ＮＯ＿３，（Ｃｕ，Ｚｎ）＿５（ＣＯ＿３）＿２（ＯＨ）＿６，（Ｃｕ，Ｚｎ）＿２ＣＯ＿３（ＯＨ）＿２，Ｚｎ＿５（ＣＯ＿３）＿２（ＯＨ）＿６；ＣｕＯ、２ｎＯ；Ｃｕ，ＺｎＯ。ＺｒＯ＿２使催化剂各组分的结晶度变得更差，晶粒更细。实验证明催化剂中ＺｒＯ＿２主要以无定形状态存在，也不排除与其它组分形成固溶体。本文还探讨了ＺｒＯ＿２提高催化活性和热稳定性的原因。认为ＺｒＯ＿２既起了载体的高分散作用，间隔活性组分作用，又起了增加和稳定活性中心的促进剂作用。     

活性碳纤维ZnO—SACF氧化还原机理的研究

本文借助于ＩＲ，ＴＧ和ＸＰＳ，研究了ＺｎＯ－ＳＡＣＦ制备过程中及其吸附Ａｇ＾＋和Ａｕ＾３＋前后的化学结构变化。实验结果表明：从ＳＡＣＦ到ＺｎＯ－ＳＡＣＦ，纤维表面上的Ｏ／Ｃ原子比和含氧基团如Ｃ＝Ｏ和ＣＯＯ都有所减少；ＺｎＯ－ＳＡＣＦ上还原性功能基团主要是－Ｃ－ＯＨ，当ＺｎＯ－ＳＡＣＦ吸附Ａｇ＾＋后，－Ｃ－ＯＨ被氧化为－Ｃ＝Ｏ，而当其吸附Ａｕ＾３＋后，－Ｃ－ＰＨ被氧化为－Ｃ＝Ｏ和－（Ｏ＝Ｃ）－ＯＨ，     

CuO－ZnO基CO_2／H_2合成甲醇催化剂的反应活性中心

应用ＸＰＳ，ＸＡＥＳ和紫外漫反射光谱法研究了ＣｕＯ－ＺｎＯ／氧化物上ＣＯ２／Ｈ２合成甲醇的反应活性中心．ＣｕＯ－ＺｎＯ／氧化物催化剂上的反应活性中心是存在于ＣｕＯ－ＺｎＯ固溶体中的Ｃｕ－Ｚｎ－Ｏ（＂□＂为氧空位），活性中心的Ｃｕ价态为Ｃｕ－和Ｃｕ０．反应活性中心在ＣｕＯＺｎＯ－ＺｒＯ２催化剂上比在其它ＣｕＯ－ＺｎＯ／氧化物催化剂如ＣｕＯ－ＺｎＯ，ＣｕＯ－ＺｎＯ－ＭｇＯ，ＣｕＯＺｎＯ－Ａｌ２Ｏ３和ＣｕＯ－ＺｎＯ－ｒ２Ｏ３上更加稳定．     

Cu, Zn─SOD酶模型化合物催化O2－歧化作用的研究

为了解Ｃｕ，Ｚｎ－ＳＯＤ酶结构和功能关系，尤其是Ｃｕ周围配位构型对催化Ｏ＾－２歧化活性的影响，本文用ＮＢＴ法测定了Ｃｕ，Ｚｎ－ＳＯＤ酶和两个Ｃｕ－ｉｍ－Ｚｎ模型配合及相应单核配合物催化Ｏ＾＿２歧化的活性，结果表明不同咪唑桥联方式和不同配位构型的化合物催化Ｏ＾－２歧化的活性明显不同。     

CuO还原过程中载体和添加物Pd的作用研究

本文用程序升温还原和电导平行测定方法考察了载体SnO_2、ZnO和Al_2O_3及金属Pd对CuO还原行为的影响。结果表明, SnO_2、ZnO等载体的电子性质对担载的CuO的还原有重要作用, 在H_2气氛下具有n-型半导性的载体可作为电子中继物, 可有效地促进CuO的还原。     

合成ZnO纳米阵列及刺突状CuO/ZnO异质结

采用低温水热法在掺氟SnO₂ (FTO)导电玻璃表面制备ZnO纳米阵列, 研究了前驱体溶液浓度摩尔配比对ZnO纳米阵列形貌、光学性能及其生长机理的影响. 研究发现, 随着前驱体溶液浓度摩尔配比的增加, ZnO纳米阵列形貌及光学性能也随之变化. ZnO纳米阵列高度逐渐降低, ZnO纳米阵列直径和光学带隙值大体上出现先增大后降低的趋势. 而当前驱体溶液(Zn(NO₃)₂:环六亚甲基四胺(HMT, C₆H₁₂N₄))浓度摩尔配比为5:5时, 其光学禁带值(3.2 eV)接近于理论值. 结果显示制备ZnO纳米阵列的最优浓度摩尔配比为5:5. 随后选用最优浓度摩尔配比下制备的ZnO纳米阵列为基底, 通过一种两步溶液法成功在其表面制备刺突状CuO/ZnO异质结.从场发射扫描电镜(FE-SEM)结果中可以清楚看见, 大量的CuO纳米粒子沉积在ZnO纳米阵列表面形成刺突状异质结结构.研究发现该CuO/ZnO纳米异质结相对于纯ZnO纳米阵列在紫外光下光催化性能明显增加. 最后, 讨论了CuO/ZnO纳米异质结光催化机理.     

Band structure tuning of ZnO/CuO composites for enhanced photocatalytic activity

The toxic dye pigments, even in small quantities, can damage ecosystems. Removing organic, inorganic, and microbiological contaminants from wastewater via heterogeneous photocatalysis is a promising method. Herein, we report the band structure tuning of ZnO/CuO nanocomposites to enhance photocatalytic activity. The nanocomposites were synthesized by a chemical approach using step-wise implantation of p-type semiconductor CuO to n-type semiconductor ZnO. Various characterization techniques such as X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and UV spectroscopy were used to investigate the crystal structure, surface morphology, elemental composition and optical properties of the synthesized samples. As the CuO content increased from 10% to 50% in ZnO/CuO nanocomposites, the optical bandgap decreased from 3.36 to 2.14 eV. The photocatalytic activity of the samples was evaluated against the degradation of methylene blue (MB) under visible irradiation. Our study demonstrates a novel p–n junction oxide photocatalyst based on wt. 10% CuO/ZnO with superior photocatalytic activity. Effectively 66.6% increase in degradation rate was achieved for wt. 10% CuO/ZnO nanocomposite compared to pure ZnO nanoparticles.     

ZnO/CuO hetero-hierarchical nanotrees array: hydrothermal preparation and self-cleaning properties

ZnO/CuO heterohierarchical nanotrees array has been prepared via a simple hydrothermal approach combined with thermal oxidation method on Cu substrates. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometer(XRD) are employed to characterize and analyze the as-synthesized samples. The results demonstrate that the secondary growth of ZnO nanorods enclose with CuO nanowires, leading to the formation of ZnO/CuO heterohierarchical nanotrees array. The hierarchical nanostructures have isotropic crystal symmetry and they have no 6-fold (or 4-fold or 2-fold) symmetry as general epitaxial growth. Enlightened by the similarity with microstructure of lotus, the wettability of ZnO/CuO heterohierarchical nanotrees array has been investigated. It is revealed that as-prepared ZnO/CuO nanotrees array after silanization present remarkable superhydrophobic performance, which is attributed to the trapped air and hierarchical roughness. Furthermore, their wettability could be manipulated by the morphologies of hierarchical ZnO nanorods. At the optimal condition, the greatest static angle of water droplet on the obtained heterohierarchical nanotrees array could reach almost 170°, and this substrate could be used as self-cleaning surface.     

Effects of the Calcination and Reduction Conditions on a Cu/ZnO Methanol Synthesis Catalyst

The CuO crystallite size of the catalysts obtained from aurichalcite greatly depends on the heating rate of calcination for highly active and selective Cu/ZnO catalyst was prepared by reduction with methanol at 443 K for 17 h.     

Growth and morphological studies of NiO/CuO/ZnO based nanostructured thin films for photovoltaic applications

At present, inorganic semiconducting materials are the most economical and viable source for the renewable energy industry. The present work deals with the morphological and optical characterization of copper oxide (CuO) and zinc oxide (ZnO) thin films fabricated by layer by layer deposition on nickel oxide (NiO) coated indium tin oxide (ITO) glass by solution processing methods, mainly chemical bath deposition (CBD) and hydrothermal deposition (HTD) processes at room temperature. As a whole, the above inorganic composite materials (NiO/CuO/ZnO) can be applied in photovoltaic cells. An attempt has been made to study structural, morphological and absorption characteristics of NiO/CuO/ZnO heterojunction using state of the art techniques like X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV spectroscopy. The energy band gaps of CuO and ZnO have also been calculated and discussed based on the UV spectroscopy measurements.     

CuO/ZnO Nanocomposite Gas Sensors Developed by a Plasma‐Assisted Route

CuO/ZnO nanocomposites were synthesized on Al₂O₃ substrates by a hybrid plasma‐assisted approach, combining the initial growth of ZnO columnar arrays by plasma‐enhanced chemical vapor deposition (PE‐CVD) and subsequent radio frequency (RF) sputtering of copper, followed by final annealing in air. Chemical, morphological, and structural analyses revealed the formation of high‐purity nanosystems, characterized by a controllable dispersion of CuO particles into ZnO matrices. The high surface‐to‐volume ratio of the obtained materials, along with intimate CuO/ZnO intermixing, resulted in the efficient detection of various oxidizing and reducing gases (such as O₃, CH₃CH₂OH, and H₂). The obtained data are critically discussed and interrelated with the chemical and physical properties of the nanocomposites.