Preparation of CuO/SiO<Subscript>2</Subscript> Hollow Spheres for Catalytic Oxidation of Phenol

Porous CuO/SiO₂ hollow microspheres were synthesized via an impregnation method using pure SiO₂ hollow microspheres as the supporter, and Cu species as the functional material. The hollow microspheres were characterized by X-ray diffraction, BET surface area, temperature-programmed reduction, transmission electron microscopy, and scanning electron microscopy. The catalytic activities of the CuO/SiO₂ hollow microspheres were investigated via the removal of the total chemical oxygen demand (COD) in the oxidation of phenol solution with air as an oxidant. The influence of various reaction parameters such as the reaction temperature, the partial pressure of O₂, and the initial pH of the solution were studied in detail. The coordination, dispersion and aggregation degree of copper species on porous materials play an important role for the COD removal of the phenol aqueous solution.     

硫化铜空心球的合成和生长机理及其在抗肿瘤中的应用

以Cu(NO_3)_2·3H_2O,H_2C_2O_4和Na_2S·9H_2O为原料,利用简易水热方法合成了笼状硫化铜空心球。所得产物用X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)进行了表征,并研究了其可能的形成机理。所得CuS空心球具有较高的光热转换性能,在近红外光辐照下,对肿瘤细胞具有明显的光热毒性。     

NiO纳米片和多孔纳米片自组装的空心微球的无模板水热法制备与磁学性质

报道一种非常简单的制备NiO和Ni(OH)₂空心微球的无模板水热法, 即通过NiCl₂与氨水在140 ℃水热反应12 h, 制备了Ni(OH)₂纳米片自组装的空心微球, 经400 ℃热处理2 h得到了NiO空心微球. 采用X射线衍射仪、扫描电镜和透射电子显微镜对产物进行表征, 并在室温下测试了它的磁学性能, 结果表明, Ni(OH)₂空心微球的直径约为3～4 μm, 它是由尺寸1.1～1.3 μm左右的六方相结构的Ni(OH)₂纳米片组装而成; NiO空心微球是由立方相纳米片和多孔纳米片组装而成, 它具有弱的铁磁性, 其矫顽力为583 Oe, 剩余磁化强度为0.213 emu/g. 研究了氨在Ni(OH)₂纳米片的形成与组装过程中的作用, 提出了可能的生长机理.     

O/W/O double emulsion-assisted synthesis and catalytic properties of CeO2 hollow microspheres

CeO₂ hollow microspheres have been fabricated through a simple thermal decomposition of precursor approach. The precursor with an average size of 10 μm was prepared in a reverse microemulsions containing Ce(NO₃)₃·6H₂O and CO(NH₂)₂ at 160 °C. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED) and scanning electron microscopy (SEM). The possible formation mechanism of hollow spheres was discussed. In addition, the CeO₂ hollow microspheres modified glassy carbon electrode exhibit excellent sensing performance towards methyl orange, which provide a new application of CeO₂ hollow spheres. The catalytic activity of CeO₂ hollow spheres on the thermal decomposition of ammonium perchlorate (AP) also was investigated by TGA. The catalytic performance of CeO₂ hollow spheres is superior to that of commercial CeO₂ powder.     

Porous α-Fe2O3 hollow microspheres and their application for acetone sensor

Porous α-Fe₂O₃ hollow microspheres were synthesized through a simple and efficient carbon sphere template method. The samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and N₂ adsorption-desorption. Structural characterization indicated that as-prepared α-Fe₂O₃ hollow microspheres had porous structure with around 200 nm in diameter and thin shell about 10 nm thick. The average pore size and Brunauer-Emmett-Teller specific surface area of α-Fe₂O₃ hollow microspheres were 6.5 nm and 111.6 m²/g, respectively. The gas sensing behavior investigation showed that as-synthesized α-Fe₂O₃ hollow microspheres exhibited very good gas sensing property to acetone vapor.     

Cobalt oxide hollow microspheres with micro- and nano-scale composite structure: Fabrication and electrochemical performance

Co₃O₄ hollow microspheres with micro- and nano-scale composite structure self-assembled by nanosheets were successfully fabricated by the template-free wet-chemical approach. This method is simple, facile and effective. The Co₃O₄ hollow microspheres with good purity and homogeneous size were well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform IR (FTIR), thermogravimetric analysis (TGA) and inductively coupled plasma atomic emission spectrometer (ICP). The formation mechanism was deeply studied. The micro- and nano-scale composite structure constructed by the porous nanosheets promotes to improve the electrochemical properties of Co₃O₄ hollow microspheres. The high discharge capacity of 1048 mAh g⁻¹ indicates it to be the potential application in electrode materials of Li-ion battery.     

Morphologically controlled synthesis of copper oxides and their catalytic applications in the synthesis of propargylamine and oxidative degradation of methylene blue

Alcohol/nonionic polymeric surfactant assisted, morphologically controlled synthesis is developed for micro-/nanostructured crystalline copper oxide. Materials were characterized by a complementary combination of X-ray diffraction (XRD), nitrogen sorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and UV-visible spectroscopy. XRD and FT-IR confirm the formation of a mixture of Cu(OH)₂ and CuO after 0.5 h of hydrothermal treatment and pure CuO after 2 h of hydrothermal treatment. The formation mechanisms were proposed based on the SEM and TEM analysis, which show that both, alcohol/polymeric surfactant and hydrothermal time play an important role in tuning the morphology and structure of CuO. Surface area of metal oxides depends on the alcohols and the nonionic polymeric surfactants used in the synthesis. Surface area of CuO synthesized using methanol was found to be the highest. The catalytic activity of as-synthesized CuO was demonstrated by using three-component coupling reaction in the synthesis of propargylamine and catalytic oxidation of methylene blue in the presence of hydrogen peroxide. Among the CuO prepared in this study, the CuO synthesized using methanol exhibited better catalytic activity (propargylamine yield (64.5%)) and the highest rate of methylene blue degradation (13 × 10⁻³ min⁻¹).     

Uniform In2S3 octahedron-built microspheres: Bioinspired synthesis and optical properties

Uniform In₂S₃ octahedron-built microspheres were synthesized by using a mild hydrothermal treatment in the presence of L-glutamic acid at 180 °C. The microsphere with an average size of 5 μm was composed of interconnected octahedrons with diameters in the range from 100 to 150 nm. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS). The synthesis of various hollow and solid sphere structures and flower structures was achieved using different amino acids. This is the first report on synthesizing In₂S₃ nanostructures using different amino acids to modulate the morphology of the final products. Primary photoluminescence studies on the prepared In₂S₃ microspheres show promising results.     

Fabrication of high-performance supercapacitors based on hollow SnO2 microspheres

Hollow SnO₂ microspheres are prepared from resorcinol–formaldehyde gel and different tin compound precursors, including stannous sulfate (SnSO₄), stannous chloride dihydrate (SnCl₂·2H₂O), and stannic chloride pentahydrate (SnCl₄·5H₂O) via chemically induced self-assembly in hydrothermal environment. Morphological and structural characterizations of as-prepared hollow SnO₂ microspheres are carried out using scanning electron microscopy, X-ray diffraction, and nitrogen adsorption–desorption method. Their electrochemical properties as the supercapacitor electrode materials for application are also investigated using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurement in 1 M H₂SO₄ electrolyte. There are redox peaks in CV curves and a large number of Faradic plateaus in GCD curves. At different scan rates, all the obtained samples have excellent electrochemical properties. The hollow SnO₂ microspheres obtained from SnSO₄ and SnCl₂·2H₂O as precursors show relatively lower specific capacitances of 395 and 347 F g^?1, respectively. However, the specific capacitance of SnO₂ from SnCl₄·5H₂O is up to 663 F g^?1. The high specific surface area and hollow structure of SnO₂ microspheres are due to facilitating the rapid transport of electrolyte ions and improving the electrochemical performance. It is expected that hollow SnO₂ microspheres are the promising redox supercapacitor materials.     

A facile synthesis of luminescent YVO4:Eu3+ hollow microspheres in virtue of template function of the SDS–PEG soft clusters

Hollow europium-doped yttrium orthovanadate (YVO₄:Eu³⁺) microspheres were fabricated via a sodium dodecyl sulfate (SDS)–polyethylene glycol (PEG)-assisted hydrothermal technique. The as-synthesized hollow YVO₄:Eu³⁺ microspheres were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). The obtained results showed that the morphology and size of the hollow microspheres have a strong dependence on the hydrothermal reaction time of the YVO₄:Eu³⁺ powders. It is believed that the SDS–PEG clusters perform a function of dual soft-template that results in a unique template-induced secondary assembly in the one-pot synthesis of hollow YVO₄:Eu³⁺ microspheres. The photoluminescence measurement revealed that the YVO₄:Eu³⁺ powders with a spherical hollow shape have better red luminescence compared to the YVO₄:Eu³⁺ solid microspheres. As a result, the controlled synthesis of hollow YVO₄:Eu³⁺ microspheres not only has a great theoretical significance in studying the three-dimensional control and selective synthesis of inorganic materials but also benefits the potential applications based on hollow YVO₄:Eu³⁺ microspheres owing to reducing the usage of expensive rare-earth elements.     

多孔氧化铜空心微球的一步法制备及其光催化性能

采用一步法成功制备出多孔氧化铜空心微球,用SEM、XRD和FTIR对制得的样品进行了表征。研究发现,碳源、反应温度、反应时间、CuSO4浓度等实验条件在多孔微球的制备过程中起着重要作用。在实验结果的基础上,提出了多孔氧化铜空心微球的形成机理。制备的多孔氧化铜空心微球的比表面积为409 m2.g-1,平均孔径为3.15 nm,总孔体积为0.256 cm3.g-1,这种空心微球具有量子尺寸效应并对罗丹明B有较高的光催化性能。     

Non-enzymatic electrochemical CuO nanoflowers sensor for hydrogen peroxide detection

The electrocatalytic activity of a CuO flower-like nanostructured electrode was investigated in terms of its application to enzyme-less amperometric H₂O₂ sensors. The CuO nanoflowers film was directly formed by chemical oxidation of copper foil under hydrothermal condition and then used as active electrode material of non-enzymatic electrochemical sensors for H₂O₂ detection under alkaline conditions. The sensitivity of the sensor with CuO nanoflowers electrode was 88.4 μA/mM cm² with a linear response in the range from 4.25 × 10⁻⁵ to 4 × 10⁻² M and a detection limit of 0.167 μM (S/N = 3). Excellent electrocatalytic activity, large surface-to-volume ratio and efficient electron transport property of CuO nanoflowers electrode have enabled stable and highly sensitive performance for the non-enzymatic H₂O₂ sensor.     

CuO负载空心球状BiVO_4可见光矿化气相甲苯

以碳球为模板,采用溶胶-凝胶法制备空心球状BiVO4,浸渍法制备CuO负载BiVO4.运用X射线衍射(XRD)、扫描电镜(SEM)、高分辨率透射电镜(HRTEM)、Brunauer-Emmett-Teller(BET)、塔菲尔(Tafel)、线性扫描(LSV)、光电转化效率(IPCE)、紫外-可见漫反射光谱(UV-Vis-DRS)等手段对催化剂进行表征.结果表明,空心球状BiVO4比表面积(10.24 m2?g-1)是无定型BiVO4(1.97 m2?g-1)的5.20倍.负载CuO后,与BiVO4形成p-n型异质结结构.其中,5%负载量的空心球状BiVO4具有最佳电化学性能,Tafel表征腐蚀电流密度(2.22μA?cm-2)为空心球状BiVO4(0.18μA?cm-2)的12.33倍,禁带宽度减小为2.30 eV.以甲苯为模型污染物研究催化剂对挥发性有机化合物(VOCs)的催化去除和矿化效果,5%CuO负载量的空心球状BiVO4光催化氧化能力最佳,可见光照6 h甲苯降解率达85.0%,矿化率达12.0%.     

Fabrication of Pt/polypyrrole hybrid hollow microspheres and their application in electrochemical biosensing towards hydrogen peroxide

Pt/polypyrrole (PPy) hybrid hollow microspheres were successfully prepared by wet chemical method via Fe₃O₄ template and evaluated as electrocatalysts for the reduction of hydrogen peroxide. The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), inductive coupled plasma emission spectrum (ICP) and Fourier-transform infrared spectra (FTIR) measurements. The results exhibited that ultra-high-density Pt nanoparticles (NPs) were well deposited on the PPy shell with the mean diameters of around 4.1 nm. Cyclic voltammetry (CV) results demonstrated that Pt/PPy hybrid hollow microspheres, as enzyme-less catalysts, exhibited good electrocatalytic activity towards the reduction of hydrogen peroxide in 0.1 M phosphate buffer solution (pH = 7.0). The composite had a fast response of less than 2 s with linear range of 1.0-8.0 mM and a relatively low detection limit of 1.2 μM (S/N = 3). The sensitivity of the sensor for H₂O₂ was 80.4 mA M⁻¹ cm⁻².     

CTAB-assisted synthesis and photocatalytic property of CuO hollow microspheres

CuO hollow microspheres have been fabricated through a simple hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB). The products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The effects of reaction temperature, surfactant, and the molar ratio of Urea/Cu(Π) on the morphologies of the resulting products were investigated. The possible formation mechanism of CuO hollow dandelion-like architectures was proposed. The hierarchical CuO hollow microspheres exhibited a high photocatalytic activity for decolorization of Rhodamine B (RhB) under UV-light illumination.     

锌离子掺杂的二氧化钛介孔空心微球的制备及光催化性能

以二氧化硅为模板,钛酸四丁酯(TBOT)为钛源,硝酸锌为锌源,采用溶胶凝胶法制备了锌离子掺杂的介孔二氧化钛空心微球。采用X射线衍射(XRD)、比表面积(BET)、透射电镜(TEM)、扫描电镜(SEM)和X射线光电子能谱(XPS)等技术对样品进行表征,以亚甲基蓝(MB)的光催化降解为目标反应评价其光催化活性。结果表明,去核之后的复合微球为空心微球,壁厚为20 nm左右。钛酸四丁酯溶液的滴加时间对微球的形貌影响较大,当滴加时间大于15 min时,可以得到结构清晰的空心微球。用氢氧化钠溶液去除二氧化硅核,反应90 min,二氧化硅可以被完全去除。X射线衍射表明,实验得到的掺杂锌离子的空心微球和没有掺杂锌离子的空心微球都是锐钛矿。当锌离子的摩尔分数为0.3%时,二氧化钛空心微球的晶粒尺寸最小,比表面积最大,催化亚甲基蓝降解的效率最高。     

锌离子掺杂的二氧化钛介孔空心微球的制备及光催化性能

以二氧化硅为模板,钛酸四丁酯（TBOT）为钛源,硝酸锌为锌源,采用溶胶凝胶法制备了锌离子掺杂的介孔二氧化钛空心微球。采用X射线衍射（XRD）、比表面积（BET）、透射电镜（TEM）、扫描电镜（SEM）和X射线光电子能谱（XPS）等技术对样品进行表征,以亚甲基蓝（MB）的光催化降解为目标反应评价其光催化活性。结果表明,去核之后的复合微球为空心微球,壁厚为20nm左右。钛酸四丁酯溶液的滴加时间对微球的形貌影响较大,当滴加时间大于15min时,可以得到结构清晰的空心微球。用氢氧化钠溶液去除二氧化硅核,反应90min,二氧化硅可以被完全去除。X射线衍射表明,实验得到的掺杂锌离子的空心微球和没有掺杂锌离子的空心微球都是锐钛矿。当锌离子的摩尔分数为0.3%时,二氧化钛空心微球的晶粒尺寸最小,比表面积最大,催化亚甲基蓝降解的效率最高。     

A facile bubble-assisted synthesis of porous Zn ferrite hollow microsphere and their excellent performance as an anode in lithium ion battery

Pure porous hollow Zn ferrite (ZnFe₂O₄) microspheres have been successfully synthesized by a facile bubble assisted method in the presence of ammonium acetate (NH₄Ac) as an anode material in lithium ion battery. The shape, size, and morphology of Zn ferrite are investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Furthermore, the probable bubble-assisted formation mechanism of porous hollow Zn ferrite spheres based on the experimental results is proposed. With the porous hollow structure, the obtained pure Zn ferrite particle as an anode in lithium ion battery demonstrates high capacity and excellent cycle ability. The high initial discharge specific capacity is approximately 1,400 mAh g^?1 and a reversible specific capacity approaches 584 mAh g^?1 after 100 cycles at a constant current density of 100 mA g^?1. The excellent electrochemical performance of the as-prepared Zn ferrite could be attributed to the special structure with which the volume expansion and pulverization of the particles became increasingly reduced.     

Construction of Cu-Ce interface for boosting toluene oxidation: Study of Cu-Ce interaction and intermediates identified by in situ DRIFTS

A facile hydrothermal method was applied to gain stably and highly efficient CuO-CeO₂ (denoted as Cu1Ce2) catalyst for toluene oxidation. The changes of surface and inter properties on Cu1Ce2 were investigated comparing with pure CeO₂ and pure CuO. The formation of Cu-Ce interface promotes the electron transfer between Cu and Ce through Cu²⁺ + Ce³⁺ ↔ Cu⁺ + Ce⁴⁺ and leads to high redox properties and mobility of oxygen species. Thus, the Cu1Ce2 catalyst makes up the shortcoming of CeO₂ and CuO and achieved high catalytic performance with T₅₀ = 234 °C and T₉₉ = 250 °C (the temperature at which 50% and 90% C₇H₈ conversion is obtained, respectively) for toluene oxidation. Different reaction steps and intermediates for toluene oxidation over Cu1Ce2, CeO₂ and CuO were detected by in situ DRIFTS, the fast benzyl species conversion and preferential transformation of benzoates into carbonates through C=C breaking over Cu1Ce2 should accelerate the reaction.