纳米级Cu2O的制备及其对四硝基苯酚的光催化性能

以NaBH4为还原剂,采用成核晶化隔离法和还原-氧化法相结合制备了纳米级Cu2O。采用XRD,SEM,EDS,UV-vis等方法对产物的结构、组成及光谱特征进行了研究。结果表明,与传统方法相比,采用成核晶化隔离法和还原-氧化法相结合的方法制得的Cu2O具有形貌均一、粒径小、分布窄等特点。光催化实验表明,所得的Cu2O对四硝基苯酚有较高的光催化活性。     

超细纳米Fe2O3及其组装结构的可见光催化性能

利用水热法成功地制备出超细氧化铁(Fe2O3)纳米颗粒及其再组装纳米饼和纳米环结构。通过X线衍射(XRD)仪、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氮吸附（BET）和UV Vis分别对样品的结构、形貌、比表面积和光学性能进行了表征，结果表明超细Fe2O3纳米颗粒的平均直径约为5.5 nm，比表面积高达256.2 m2·g-1。通过控制反应时间等实验条件，可将Fe2O3超细纳米颗粒三维定向组装为饼状结构，经腐蚀镂空可进一步演化为纳米环状结构。这些结构表面由超细纳米颗粒相互联结，能够提供大量的活性位点。可见光照射下的罗丹明B光催化降解实验表明，Fe2O3纳米饼状再组装结构具有优异的可见光催化活性，且性能稳定，易回收。这些特性使得Fe2O3超细纳米颗粒及其再组装结构材料在光催化领域具有较大的实用价值。     

Cu2O颗粒的制备及其吸附性能北大核心

通过液相还原法制备了Cu2O颗粒,利用扫描电子显微镜（SEM）以及X射线衍射（XRD）等手段对粒径的大小、微结构以及组分进行了测试和分析。测试结果表明：Cu2O颗粒为组分单一、表面含有大量孔隙的八面体结构。颗粒的粒径大小并不均匀,分布在几十纳米到1微米之间。同时研究了Cu2O颗粒的吸附特性,发现Cu2O颗粒对甲基橙具有良好的吸附能力。在吸附160min后,甲基橙的吸附率为67．5％,而且其最高吸附率可达94．86％。Cu2O颗粒的吸附性能可能主要来源于颗粒上的孔隙结构。拟合结果表明Cu2O颗粒的吸附过程符合伪一级动力学方程,这说明Cu2O颗粒的吸附机制主要是物理吸附。     

γ-Fe2O3@C复合材料的制备及其光催化性能

氧化铁(Fe2O3)导电性能差、可见光吸收范围窄、电子-空穴对复合速率过快等一系列问题极大限制了其在光催化领域的应用.通过简单的水热法,调控葡萄糖的添加量,合成不同碳含量的γ-Fe2O3@C异质结复合材料.研究结果表明,γ-Fe2O3与碳层之间的光电协同效应可有效降低光生载流子的复合速率,并明显改善光催化性能.当调控葡...     

Cu2O镂空材料的制备及其光催化性能研究

采用空气氧化法制备了六角状氧化亚铜的镂空结构。在空气中氧气的辅助下,液相还原法制备的形貌、尺寸均一的六角状氧化亚铜（Cu2O）可被原位镂空成鱼骨状结构。采用扫描电镜(SEM)、X线衍射(XRD)、透射电子显微镜（TEM）、比表面积测试（BET)、紫外 可见吸收（UV Vis）光谱等手段对Cu2O材料进行形貌、结构及催化性能表征。结果表明,六角状Cu2O沿{100}和{111}面逐步向内腐蚀镂空,在空气辅助腐蚀2 h后,材料的比表面积相比镂空前增加了90％。光催化实验结果表明,镂空Cu2O材料的光催化性能提高了30％。     

激光原位合成颗粒尺寸对铁基复合涂层耐磨性的影响

为研究增强颗粒的分布状态对颗粒增强金属基复合材料涂层耐磨性的影响,运用原位合成复合碳化物的思想,通过控制强碳化物形成元素之间的成分配比,用激光熔覆的方法在45钢表面制备了原位复合碳化物颗粒增强铁基复合涂层,涂层具有预期典型的颗粒分布特征.通过常温油润滑重载荷下的MHK环块磨损对比实验,研究了不同颗粒尺寸下涂层的耐磨性能.研究表明:相对于常规表面处理方式,激光原位合成颗粒增强复合涂层具有优异的耐磨性能,但颗粒平均尺寸的差异对涂层耐磨性具有显著影响.颗粒尺寸过大或过小都不利于耐磨性能的提高,只有具有适当尺寸的颗粒才有利于获得最高的耐磨性能.最后优选了涂层具有最佳耐磨性能时颗粒的分布状态.     

水热法合成多孔六边形α-Fe_2O_3纳米颗粒及其表征(英文)

报道了一种不同尺寸多孔六边形α-Fe2O3纳米颗粒的简单、高产合成方法。对所合成的多孔纳米材料进行了X射线衍射、X射线光电子谱、激光喇曼光谱、场发射扫描电镜和透射电子显微镜的表征。所得结果都表明所合成出来的样品为高选择性的多孔六边形α-Fe2O3纳米颗粒。通过系统地控制实验条件,研究了反应时间、铁盐的种类、反应物的起始浓度对所合成样品的影响。通过对所得实验结果的系统对比和分析,给出了该种结构α-Fe2O3纳米颗粒的形成机制。因而,在此报道了一种简单(仅需FeCl3.6H2O和NH4HCO3两种反应物)、一步、经济、可重复性高的多孔六边形α-Fe2O3纳米颗粒的高产合成方案,并且该方案不需要使用任何有机溶剂。     

Cu_2O不同形貌的研究进展

近年来,Cu2O形貌控制合成的研究受到了广泛关注。首先,介绍了Cu2O一维、二维、三维结构中不同形貌的最新研究成果,分析了不同形貌的合成机理,并对各形貌的进一步研究趋势进行了探讨。然后,着重评述了Cu2O纳米笼、纳米骨架结构的研究进展,指出此类形貌的合成中主要涉及到氧化刻蚀作用和奥斯特瓦尔德熟化机理。最后,总结了Cu2O不同形貌研究的现状,指出了今后研究的方向,并提出了未来关于Cu2O形貌研究中主要的两大类趋势,即具有更多晶面的非传统型多面体结构以及具有更大比表面积、更高开放程度的纳米笼和纳米骨架结构。     

Y2O3增强Sn-3Ag-0.5Cu复合无铅钎料

研究了稀土氧化物颗粒增强复合无铅钎料Sn-3Ag-0.5Cu-Y2O3的钎焊接头的显微组织形貌、性能特点及有关影响机制.结果表明:Y2O3增强颗粒均匀分布于Sn-3Ag-0.5Cu钎料基体中,不仅细化了钎焊接头中共晶相Ag3Sn和Cu6Sn5相颗粒尺寸,而且也显著提高了钎焊接头的剪切强度.另外适量Y2O3颗粒的添加对钎料润湿性影响不大.     

SO_4~(2-)/Bi_2O_3固体超酸的制备及其可见光催化性能

采用水热法结合H2SO4浸泡处理成功合成了SO42-/Bi2O3可见光催化材料,并采用XRD、TG-DTA和UV-Vis等对合成产物的物相结构、热化学性能、光吸收性能以及可见光催化性能进行了研究,对H2SO4浸泡工艺条件对产物的可见光催化性能的影响进行了探讨。研究表明,水热合成产物为α-Bi2O3、Bi2O4和Bi2O2CO3的混合物,其中α-Bi2O3为主要成分;H2SO4浸泡处理并未改变产物的物相结构,但经H2SO4浸泡处理后产物的光催化性能得到了显著的提高,并且H2SO4浸泡工艺条件对产物的光催化活性有着重要的影响。在实验范围内,在浓度为0.5mol·L-1的H2SO4溶液中浸泡75min,再经700℃热处理4h可制备出具有较佳光催化活性的产物,经75min可见光的照射后对甲基橙溶液的光催化脱色率可达93.1%。     

Facile synthesis of Cu/tetrapod-like ZnO whisker compounds with enhanced photocatalytic properties

Cu/tetrapod-like ZnO whisker (T-ZnOw) compounds were successfully synthesized using N₂H₄·H₂O as a reducing agent by a simple reduction method without any insert gas at room temperature. The crystal phase composition and morphology of the as-prepared samples were investigated by XRD, SEM and FESEM tests. The photocatalytic property of the as-prepared samples was detected by the degradation of methyl orange (MO) aqueous solution under UV irradiation. It can be found that Cu nanoparticles (CuNPs) dispersed on the surface of T-ZnOw increased with the increasing of Cu/Zn molar ratios (Cu/Zn MRs), and an octahedral structure of CuNPs was obtained when the sample was prepared with less than and equal to 7.30% Cu/Zn MR, but tended to a spherical or nanorod structure of CuNPs densely arranged on the surface of T-ZnOw, which is prepared by Cu/Zn MRs up to 22.00%. All the compounds exhibited excellent photocatalytic activity in decomposing of MO than T-ZnOw, the photocatalytic property of the samples increased with the increasing of Cu/Zn MRs up to 7.30%, while it decreases when further increasing the Cu/Zn MRs. The Schottky barrier of the Cu/T-ZnOw compound can effectively capture photoinduced electrons from the interface and enhanced the photocatalytic property of T-ZnOw.     

Preparation and photocatalytic activities of 3D flower-like CuO nanostructures

Hierarchical 3D flower-like CuO nanostructures on the Cu substrates were synthesized by a wet chemical method and subsequent heat treatment. The synthesis, structure and morphologies of obtained samples under different concentrations of Na₂S₂O₃ were investigated in detail and the possible growth mechanisms of the 3D flower-like CuO nanostructures were discussed. Na₂S₂O₃ plays a key role in the generation of the 3D flower-like CuO nanostructures. When the concentration of Na₂S₂O₃ is more than 0.4 mol/L, the 3D flower-like CuO nanostructures can be prepared on the Cu foils. The photocatalytic performances were studied by analyzing the degradation of methyl orange (MO) in aqueous solution in the presence of hydroxide water (H₂O₂). The 3D flower-like CuO nanostructures exhibit higher photocatalytic activity (96.2% degradation rate) than commercial CuO particles (36.3% degradation rate). The origin of the higher photocatalytic activity of the 3D flower-like CuO nanostructures was also discussed.     

Tunable crystal structure of Cu–Zn–Sn–S nanocrystals for improving photocatalytic hydrogen evolution enabled by copper element regulation

Hydrogen energy is a powerful and efficient energy resource, which can be produced by photocatalytic water splitting. Among the photocatalysis, multinary copper-based chalcogenide semiconductor nanocrystals exhibit great potential due to their tunable crystal structures, adjustable optical band gap, eco-friendly, and abundant resources. In this paper, Cu–Zn–Sn–S (CZTS) nanocrystals with different Cu content have been synthesized by using the one-pot method. By regulating the surface ligands, the reaction temperature, and the Cu content, kesterite and hexagonal wurtzite CZTS nanocrystals were obtained. The critical factors for the controllable transition between two phases were discussed. Subsequently, a series of quaternary CZTS nanocrystals with different Cu content were used for photocatalytic hydrogen evolution. And their band gap, energy level structure, and charge transfer ability were compared comprehensively. As a result, the pure hexagonal wurtzite CZTS nanocrystals have exhibited an improved photocatalytic hydrogen evolution activity.     

大孔TiO_2-ZnO复合纳米材料的制备及其性能

采用溶胶-凝胶法和胶态晶体模板法,制备了大孔TiO2-ZnO复合纳米材料。其晶相结构和形貌特征采用X射线粉末衍射(XRD)、透视电子显微镜(TEM)进行了表征,并以甲基橙为降解对象,对其光催化活性进行了研究。结果表明,采用无皂乳液聚合法得到的聚苯乙烯(PS)微球粒径均匀,为900nm。以紧密堆积的PS胶态晶体为模板,制得的TiO2-ZnO复合纳米材料的大孔孔径约为900nm,孔壁厚度约为20nm。XRD结果显示,材料中的TiO2为锐钛矿型。光催化降解结果表明,大孔TiO2-ZnO复合纳米材料对甲基橙降解1.5h后降解率可达91.3%,与普通的TiO2-ZnO纳米粉体材料相比提高了11.2%.     

SiC/Cu-Al复合材料无压浸渍制备工艺的研究

利用化学镀法在SiC颗粒表面包覆Cu层制备了SiC/Cu复合粉体,然后将其压制成预制体并在熔融铝液中无压浸渍,制出了SiC/Cu-Al复合材料.研究了浸渍温度和时间对所制SiC/Cu-Al复合材料浸渍效果的影响.结果表明:SiC颗粒表面的Cu包覆层分布均匀;在800℃、保温2h条件下制备的SiC/Cu-Al复合材料显微...     

Fabrication and study of properties of the PLA/Sr2MgSi2O7:Eu2+, Dy3+ long-persistent luminescence composite thin films

In this paper, Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ (SMS) particles were first synthesized by sol–gel method and then modified with 3-aminopropyltriethoxysilane (APS) to improve their dispersibility and compatibility in the polylactic acid (PLA) matrix. The structure of pure SMS particles was analyzed by XRD and XPS. The properties of SMS particles before and after modification were characterized by FT-IR and SEM. PLA/SMS composite films containing 15 wt% of SMS particles were prepared by spin coating on silicon wafer. Their morphology and luminescence properties were examined. It was found that the composite films can be excited by a broad band from 330 nm to 425 nm with the highest excitation intensity at 360 nm. The fluorescent and phosphorescent emission bands of the composite films and SMS particles all have a major emission peak at 468 nm. Decay curves of the composite films have a similar tendency with that of the pure SMS particles, except for the lower intensity.     

Novel synthesis of cerium oxide nano photocatalyst by a hydrothermal method

Crystalline cubic cerium oxide nano particles have been synthesized from cerium (Ⅲ) nitrate (Ce (NO3)3.6H2O) and sodi-um hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH precipitating agent on structur-al,optical,and photo catalytic activity was investigated.The synthesized cerium oxide nano particles were characterized by X-ray diffraction (XRD),a UV-vis spectrometer,scanning electron microscope (SEM),energy-dispersive X-ray spectroscopy (EDAX),Raman spectroscopy and X-ray photo electron spectroscopy (XPS).According to the findings,hydrothermally synthesized ceri-um oxide NPs have a high efficiency for photocatalytic degradation of methylene blue when exposed to UV light.Environment-al water pollution is the major issue of the atmosphere.To get fresh water,humans could search the resources to purify the wa-ter in simple way and degradation is the one of the methods to purify salt water.     

Highly enhanced photoelectric catalysis of WO3 nanoblocks loaded with Ag nanoparticles

WO3/Ag composite film photoanodes were synthesized by hydrothermal combined electrodeposition method. Characterization of samples was conducted by scanning electron microscope (SEM) and X-ray diffraction (XRD), which showed that WO3/Ag composite films had been synthesized. Diffuse reflectance spectra show WO3/Ag composite film has more strong absorption than WO3 film under simulated visible light irradiation. Electrochemical impedance spectroscopy shows WO3/Ag composite film photoanode enhances charge transfer efficiency compared with WO3 film. WO3/Ag composite film photoanodes show higher photocurrent and photoelectric catalytic activity than WO3 film, and the WO3/Ag composite film obtained by depositing Ag nanoparticles at 50 s (WO3/Ag-50) shows the highest photocurrent and photoelectric photoelectric catalytic activity. Meanwhile, the photoelectric catalytic activity of the composite film is higher than their direct photocatalytic and electric catalytic activity. The higher photocurrent and photoelectric catalytic activity of the WO3/Ag composite film photoanodes are attributed to the surface plasmon resonance effect of Ag nanoparticles and Schottky junction effect at the WO3/Ag interface.     

Photodegradation of Azo-dye by Y2O3/TiO2 Loaded on Carboxymethyl Cellulose Films

Nanosize TiO2, Y2O3/TiO2 particles were prepared by the sol-gel process. The structure was characterized by means of XRD,TEM. The photoelectric properties of the nanoparticles were studied by PL. The thickness and the surface of the carboxymethyl cellulose film was measured by SEM. Based on a model reaction, the photocatalytic degradation of methylene blue with positive charge was investigated in TiO2,Y2O3/TiO2 nanopowder composite films irradiated by UV lamp. The results revealed that the degradation process belonged to the first-order kinetic reaction.