Cu/ZSM-5分子筛催化剂SCR催化性能

采用液态离子交换法制备了不同Cu含量的Cu/ZSM-5分子筛催化剂.对其理化特性和在NH3-选择性催化还原反应中催化性能的评价结果表明:Cu元素主要以Cu+离子的形式富集于分子筛的浅层及表面,且分散性较好.Cu质量分数低于6.39%时,NO低温转化率随Cu含量的增加而增加;而在Cu质量分数超过6.39%后,随Cu含量的增加,高温NO转化率开始衰减的温度降低.反应气流速在150,000,h-1以内时,反应气流速对Cu/ZSM-5催化剂的活性温度窗口影响不大.     

Cu/ZnO/Al2O3催化剂涂层工艺参数的优化

针对甲醇水蒸汽重整制氢反应，研制了一种新型的适用于微槽道反应器的Cu/ZnO/Al2O3催化剂涂层。通过对其关键制备参数的优化，筛选出COAT-14-6（CuO 14wt．％，ZnO6wt．％）为性能最佳的催化剂涂层。研究发现Cu，ZnO／Al2O3涂层催化剂的活性与活性铜的表面积和催化剂的还原性密切相关。100h的连续性实验结果表明，涂覆了COAT-14-6的微槽道反应器可以与10W的燃料电池配套。     

ITO/Metal/ITO叠层电极中Cu/Ag对钙钛矿太阳电池电极性能的影响

研究ITO/Metal/ITO（IMI）电极中金属层Cu和Ag及其厚度对电极光电性能的影响,结合霍尔测试、紫外分光光度计、原子力显微镜等分析金属层材料和厚度对IMI电极光电性能以及形貌的影响。通过优化金属层厚度,获得方阻分别为11.2 Ω/□和14.5 Ω/□且400~800 nm波长范围内平均透过率分别为93.9%和86.5%的ITO/Ag/ITO和ITO/Cu/ITO电极。将IAI和ICI电极作为正面电极应用于钙钛矿太阳电池,太阳电池的填充因子从62.5%提升至78.0%。IMI在短波段的较大反射率会导致电池短路电流密度低1~2 mA/cm²。当Cu层和Ag层的厚度分别为7.4 nm和6.4 nm时,钙钛矿太阳电池的效率达到最佳。     

SnO_2/CrON/Cu太阳能选择性吸收涂层循环热冲击性能研究

采用DC磁控溅射法制备SnO_2/CrON/Cu太阳能光谱选择性吸收涂层并进行中低温循环热冲击试验。对所制备涂层循环热冲击试验前后的光学性能和热稳定性进行表征。该涂层沉积态的吸收比为0.927,100℃发射比为0.048,在25℃/300℃的中低温下经264.25 h的循环热冲后涂层表面粗糙度几乎不变,未出现明显的元素扩散。吸收比仅衰减为0.912,发射比仅增加为0.076。表明该涂层适用于中低温光热利用领域。     

不同ZnO/Cu2O异质结电池的光伏性能

采用电化学沉积法,分别制备薄膜/薄膜型(薄膜型)和薄膜/纳米线型(复合型)Cu2O/ZnO异质结太阳电池,并通过光吸收谱和电流-电压谱测试两类太阳电池的性能。研究发现,与薄膜型异质结太阳电池相比,复合型电池具有更高的电池转换效率。通过对两种不同太阳电池的结构表明,增大PN结面积和改善异质结界面性质是提升该类异质结太阳电池性能的重要途径。     

Characterization and activity test of commercial Ni/Al2O3, Cu/ZnO/Al2O3 and prepared Ni–Cu/Al2O3 catalysts for hydrogen production from methane and methanol fuels

In this study, methane and methanol steam reforming reactions over commercial Ni/Al₂O₃, commercial Cu/ZnO/Al₂O₃ and prepared Ni–Cu/Al₂O₃ catalysts were investigated. Methane and methanol steam reforming reactions catalysts were characterized using various techniques. The results of characterization showed that Cu particles increase the active particle size of Ni (19.3 nm) in Ni–Cu/Al₂O₃ catalyst with respect to the commercial Ni/Al₂O₃ (17.9). On the other hand, Ni improves Cu dispersion in the same catalyst (1.74%) in comparison with commercial Cu/ZnO/Al₂O₃ (0.21%). A comprehensive comparison between these two fuels is established in terms of reaction conditions, fuel conversion, H₂ selectivity, CO₂ and CO selectivity. The prepared catalyst showed low selectivity for CO in both fuels and it was more selective to H₂, with H₂ selectivities of 99% in methane and 89% in methanol reforming reactions. A significant objective is to develop catalysts which can operate at lower temperatures and resist deactivation. Methanol steam reforming is carried out at a much lower temperature than methane steam reforming in prepared and commercial catalyst (275–325 °C). However, methane steam reforming can be carried out at a relatively low temperature on Ni–Cu catalyst (600–650 °C) and at higher temperature in commercial methane reforming catalyst (700–800 °C). Commercial Ni/Al₂O₃ catalyst resulted in high coke formation (28.3% loss in mass) compared to prepared Ni–Cu/Al₂O₃ (8.9%) and commercial Cu/ZnO/Al₂O₃ catalysts (3.5%).     

衬底温度对AZO/Cu/AZO多层薄膜结构及光电特性的影响

采用射频磁控溅射和离子束溅射联合设备在玻璃衬底上制备出了具有良好附着性、低电阻率和高透过率的AZO/Cu/AZO多层薄膜.研究了衬底温度对薄膜的结构和光电特性影响.X射线衍射谱表明AZO/Cu/AZO多层薄膜是多晶膜,AZO层具有六角纤锌矿结构,最佳取向为(002)方向,Cu层具有立方结构.当三层薄膜制备过程中,衬底始终加热,衬底温度为100%℃时,制备的薄膜具有最高的品质因子2.26×10-2Ω-1,其方块电阻为11Ω·□-1,在波长500-800nm范围内平均透过率达到了87%.当制备靠近衬底的AZO层,衬底才加热时,发现衬底温度为250℃时,制备的多层薄膜光电特性最优,其方块电阻为8Ω·□-1,平均透过率为86%.     

Cu（In,Al）Se2薄膜太阳电池

Cu(In,Al)Se2(CIAS)化合物薄膜太阳电池属于Ⅰ-Ⅲ-Ⅵ2族化合物薄膜太阳电池,由同族的Al来替代CuInSe2(CIS)中的In,及Cu(In,Ga)Se2(CIGS)中的Ga和In。具有黄铜矿结构的Ⅰ-Ⅲ-Ⅵ2族化合物半导体材料可作为吸收层用于光伏电池。用渗入CIS中得到具有黄铜矿结构的CIGS,并且可根据Ga/(In+Ga)调节禁带宽度提高转化效率,但Ga的掺入调节禁带宽有限。以Al替代Ga,不仅可大幅降低成本,同时由于形成CuAlSe2相的能隙为2.7eV,因此调节Al/(In+Al)的比例可更宽泛地调节Cu(In,Al)Se2(CIAS)能禁带宽度。目前CIAS制备工艺以真空镀膜方法为主,包括真空蒸镀、磁控溅射、脉冲激光等。在非真空方法中,研究者们尝试了电沉积的方法成功制得单相的CIAS吸收层薄膜,而用如丝网印刷等低成本工艺CIAS薄膜尝试还少见报导。本文详细介绍了CIAS制备方法及工艺,并提出CIAS研究的一些建议。     

Cu源对Cu-SSZ-13催化剂脱除NOx性能的影响

通过离子交换法制备了不同Cu源（硝酸铜、硫酸铜和乙酸铜）的Cu-SSZ-13催化剂,并利用X射线衍射（XRD）、比表面积（BET）、X射线光电子能谱（XPS）、H₂程序升温还原（H₂-TPR）和NH₃程序升温脱附（NH₃-TPD）等表征手段结合固定床反应器研究了Cu源对催化剂选择性催化还原（SCR）活性的影响．结果表明：采用离子交换法制备的Cu-SSZ-13催化剂具有良好的SCR催化活性和N₂选择性,其中利用有机铜源（乙酸铜）制备的CuSSZ-13催化剂具有较好的低温催化活性和NH₃吸附稳定性．水热老化后,催化剂的NO_x转化率达到90%及以上的温度窗口(T₉₀)为175～575℃,其CHA结构的特征衍射峰强度有所降低,但结构并未发生明显变化,表明经过水热老化处理后的催化剂能够保持较高的活性．温度为300℃时,在反应进料中添加体积分数为500×10^-6的丙烯（C₃H     

Cu/La2O3/Al2O3催化剂上甲醇水蒸气重整制氢反应

研究以并流共沉淀法制备Cu/La2 O3 /Al2 O3 系列催化剂催化甲醇水蒸气重整制氢反应过程 ,考察了La2 O3含量、反应温度、水醇比、液体空速 (WHSV)等因素对催化剂活性的影响。结果表明 :催化剂表现出较好的低温活性、高氢气选择性和稳定性。La2 O3 质量分数为 15 % ,在 2 5 0℃反应时 ,催化剂活性表现最佳 ,甲醇摩尔转化率为94 .5 % ,氢气选择性为 10 0 % ,CO摩尔分数为 1.0 5× 10 -7。     

不锈钢衬底表面形貌对AlN/AlN-Cr/Cu太阳能选择性吸收涂层光热性能的影响

在数值仿真计算和实验两方面研究不锈钢衬底表面形貌对AlN/AlN-Cr/Cu太阳能选择性吸收涂层光热性能的影响。在数值仿真计算中,建立一维三角形光栅结构模型对衬底表面形貌进行简化,采用严格耦合波分析(RCWA)的方法,仿真计算并分析光栅深度T_z和周期T_x对涂层的太阳吸收比α和400℃热发射比ε的影响。实验上,制备具有不同深度和间隔起伏表面的不锈钢衬底,采用磁控溅射的方法在其上沉积相同结构参数的AlN/AlN-Cr/Cu太阳能选择性吸收涂层,测定涂层性能参数,并分析不锈钢衬底形貌对其的影响。数值计算和实验结果表明:对于一个在已优化涂层组分和厚度的AlN/AlN-CdCu太阳能选择性吸收涂层,不锈钢衬底表面起伏对涂层高温光热转换将产生不利的影响。随着不锈钢衬底表面平均起伏深度的增加,涂层的太阳吸收比α基本保持不变,而400℃时的热发射比ε则明显逐渐增大。为保证涂层有效的光热转化效率,建议不锈钢衬底表面起伏的深宽比T_z/T_x≤1/20,深度T_z≤0.2μm。     

Kinetics of methane decomposition to COx-free hydrogen and carbon nanofiber over Ni–Cu/MgO catalyst

Kinetic modeling of methane decomposition to CO_x-free hydrogen and carbon nanofiber has been carried out in the temperature range 550–650 °C over Ni–Cu/MgO catalyst from CH₄–H₂ mixtures at atmospheric pressure. Assuming the different mechanisms of the reaction, several kinetic models were derived based on Langmuir–Hinshelwood type. The optimum value of kinetic parameters has been obtained by Genetic Algorithm and statistical analysis has been used for the model discrimination. The suggested kinetic model relates to the mechanism when the dissociative adsorption of methane molecule is the rate-determining stage and the estimated activation energy is 50.4 kJ/mol in agreement with the literature. The catalyst deactivation was found to be dependent on the time, reaction temperature, and partial pressures of methane and hydrogen. Inspection of the behavior of the catalyst activity in relation to time, led to a model of second order for catalyst deactivation.     

Cu–MoS2/rGO hybrid material for enhanced hydrogen evolution reaction performance

Cu doped MoS₂ (Cu–MoS₂)/reduced graphene oxide (rGO) (Cu–MoS₂/rGO) hybrid material is fabricated by a facile one-step solvothermal method. The X-ray diffraction (XRD) results suggest that the doping of Cu does not alter the crystal structure of MoS₂. X-ray photoelectron spectroscopy (XPS) analysis reveal that the doping of Cu atoms influences the electronic structure of MoS₂, which is favorable to increase active sites of edges. Electrochemical impedance spectroscopy (EIS) results indicate that Cu–MoS₂/rGO performed a faster charge-transfer in comparison to MoS₂/rGO hybrid. In addition, the resultant Cu–MoS₂/rGO catalyst with Cu/Mo mole ratio of 9% exhibits a lower overpotential of 199 mV at 10 mA cm⁻², small Tafel slop of 44 mV dec⁻¹ and cycling stability, indicative of enhanced electrocatalytic activity towards HER. The improved performance is attributed to the increased active sites and a synergistic effect between copper and molybdenum, leading to electronic structure change and charge redistribution of MoS₂.     

Cu substituted ZnAl2O4 ex-LDH catalysts for medium-temperature WGS – effect of Cu/Zn ratio and thermal treatment on catalyst efficiency

The effect of Cu/Zn ratio of ex-LDH oxide-based catalysts for medium–temperature water–gas shift reaction (MT–WGS) was investigated. A series of CuZnAl–LDH precursors with different Cu/Zn molar ratio were synthesized by co-precipitation and oxide (Zn,Cu)_xAl₂O₄ catalysts were prepared via subsequent calcinations at 380 °C or 700 °C. The prepared materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetry with evolved gas analysis (TG/DTG/EGA), N₂ adsorption, N₂O chemisorption and temperature-programmed reduction (H₂-TPR). MT-WGS activity evaluation was carried out on the basis of measurements made in a differential reactor in kinetic regime. Catalysts’ properties were investigated and effect of composition (Cu/Zn molar ratio) and the calcination temperature of CuZnAl-LDH precursors on structural transformation, active surface area and MT-WGS rate constant was shown. The highest activity of (Zn,Cu)_xAl₂O₄ catalyst with Cu/Zn molar ratio of 1.5 calcined at mild conditions was attributed to easy reducible and accessible Cu surface.     

Production of hydrogen by methane catalytic decomposition over Ni–Cu–Fe/Al2O3 catalyst

Catalysts with high nickel concentrations 75%Ni–12%Cu/Al₂O₃, 70%Ni–10%Cu–10%Fe/Al₂O₃ were prepared by mechanochemical activation and their catalytic properties were studied in methane decomposition. It was shown that modification of the 75%Ni–12%Cu/Al₂O₃ catalyst with iron made it possible to increase optimal operating temperatures to 700–750 °C while maintaining excellent catalyst stability. The formation of finely dispersed Ni–Cu–Fe alloy particles makes the catalysts stable and capable of operating at 700–750 °C in methane decomposition to hydrogen and carbon nanofibers. The yield of carbon nanofibers on the modified 70%Ni–10%Cu–10%Fe/Al₂O₃ catalyst at 700–750 °C was 150–160 g/g. The developed hydrogen production method is also efficient when natural gas is used as the feedstock. An installation with a rotating reactor was developed for production of hydrogen and carbon nanofibers from natural gas. It was shown that the 70%Ni–10%Cu–10%Fe/Al₂O₃ catalyst could operate in this installation for a prolonged period of time. The hydrogen concentration at the reactor outlet exceeded 70 mol%.     

Hydrogen production from steam reforming of bioethanol using Cu/Ni/K/γ-Al2O3 catalysts. Effect of Ni

Hydrogen to be used as a raw material in fuel cells or even as a direct fuel can be obtained from steam reforming of bioethanol. The key aim of this process is to maximize hydrogen production, discouraging at the same time those reactions leading to undesirable products, such as methane, acetaldehyde, diethyl ether or acetic acid, that compete with H₂ for the hydrogen atoms. Cu–Ni–K/γ-Al₂O₃ catalysts are suitable for this reaction since they are able to produce acceptable amounts of hydrogen working at atmospheric pressure and a temperature of 300°C. The effect of nickel content in the catalyst on the steam-reforming reaction was analyzed. Nickel addition enhances ethanol gasification, increasing the gas yield and reducing acetaldehyde and acetic acid production.     

磁控溅射Sn/Cu/ZnS预置层后硫化法制备Cu_2ZnSnS_4薄膜及其性能研究

采用磁控溅射法制备Sn/Cu/ZnS金属预置层,结合硫化热处理制备Cu_2ZnSnS_4薄膜。利用X射线衍射仪(XRD)、拉曼光谱仪(Raman)、扫描电子显微镜(SEM)、紫外-可见分光光度计(UV-VIS)和霍尔测试系统等一系列测试方法对样品结构、各组分含量、表面形貌、光学带隙及电学性能进行表征及计算。研究结果表明Sn/Cu/ZnS金属预置层经490和540℃硫化热处理后的薄膜均为单一Cu_2ZnSnS_4相,其中,540℃硫化热处理后的薄膜结晶度较高,且薄膜表面平整致密,禁带宽度约为1.58 eV,呈现P型导电。     

Cu/ZnO/Al2O3 water–gas shift catalysts for practical fuel cell applications: the performance in shut-down/start-up operation

The Cu/ZnO/Al₂O₃ catalysts were prepared by the coprecipitation method, and were evaluated in the water–gas shift (WGS) reaction. The effects of the calcination temperature on the BET surface area and crystallite size were characterized. In WGS reaction, the Cu/ZnO/Al₂O₃ catalysts suffered from continuous deactivation in shut-down/start-up operation – the daily requirement for mobile and residential fuel cell systems. Among them, the Cu/ZnO/Al₂O₃ catalyst prepared at the calcination temperature of 450 °C showed the best activity and stability, with the decrement of the CO conversion of only 12.8% after three shut-down/start-up cycles. Deactivation of the Cu/ZnO/Al₂O₃ catalysts is attributed to the blocking or deterioration of the active sites by Zn₆Al₂(OH)₁₆CO₃·4H₂O resulting from the degeneration of the oxides under cyclic operations. Removal of the hydroxycarbonate species by calcination in air followed by re-reduction could restore the steady-state WGS activity; however, the regenerated catalyst underwent much severe deactivation in subsequent shut-down/start-up operation.     

Ce改性对Cu/SSZ-13催化剂抗钾中毒的影响机理研究

采用等体积浸渍法制备了Ce–Cu/SSZ-13、Ce–K–Cu/SSZ-13和K–Cu/SSZ-13催化剂,通过模拟气试验平台研究了Ce–Cu/SSZ-13、K–Cu/SSZ-13和Ce–K–Cu/SSZ-13催化剂的氨气选择性催化还原(NH₃ selective catalytic reduction, NH₃-SCR)性能,并且利用X射线衍射(X-ray diffraction, XRD)、比表面积(brunauer emmett teller, BET)、X射线光电子能谱(X-ray photoelectron spectrometer, XPS)和NH₃程序升温脱附(NH₃ temperature programmed desorption, NH₃-TPD)等表征手段评价碱金属钾(K)对Ce–Cu/SSZ-13催化剂理化性质的影响规律。结果表明,碱金属K的引入使得Cu/SSZ-13催化剂的NH₃-SCR性能下降,导致催化剂出现中毒失活现象。与K–...