Correction to: Synthesis of Co3O4 @ Organo/Polymeric Bentonite Structures as Environmental Photocatalysts and Antibacterial Agents for Enhanced Removal of Methyl Parathion and Pathogenic Bacteria

Journal of Inorganic and Organometallic Polymers and Materials -     

Two-Dimensional Porous PdO/Co3O4 Nanocomposites for Highly Effective Photocatalysts Under Visible-Light Exposure

Journal of Inorganic and Organometallic Polymers and Materials - Recently, great efforts have been dedicated to the construct and design of low cost and high-performance photocatalysts for the...     

Removal of Arsenic and Copper from Water Solution Using Magnetic Iron/Bentonite Nanoparticles (Fe3O4/Bentonite)

Silicon - Heavy metal pollution is one problem in the water purification industry, which causes extreme risk aversion. The purpose of this study was to investigate the removal of arsenic (As) and...     

硬脂醇@Co3O4/膨胀石墨复合相变材料的制备及性能

以硬脂醇(SAL)作为相变材料、Co3O4/膨胀石墨(EG)作为支撑材料,通过熔融共混-压制成型制备了一种复合相变材料(PCMs)SAL/Co3O4/EG-P.EG的添加用于改善PCM的导热性能,同时采用ZIF-67煅烧后得到的Co3O4对其进行了化学改性.采用SEM对Co3O4/EG-P的结构进行表征.结果表明,Co3O4/EG具有三维耦合网络和分级多孔结构,EG可以有效防止金属有机骨架衍生材料结构的坍塌和团聚.采用SEM、DSC和红外成像仪对复合PCMs的形貌和热性能进行了分析.结果表明,随着Co3O4和EG的质量比从1:1到1:8,复合PCMs的导热系数呈现上升趋势.当m(Co3O4):m(EG)=1:8时,复合PCMs的熔化温度为51.26℃,潜热为191.63 J/g,热导率大约是纯SAL〔0.248 W/(m·K)〕的47.5倍.而红外成像结果则验证了复合PCMs的瞬态温度变化与其热导率密切相关.     

Synthesis of Co3O4 Nanoparticles-Decorated Bi12O17Cl2 Hierarchical Microspheres for Enhanced Photocatalytic Degradation of RhB and BPA

Three-dimensional (3D) hierarchical microspheres of Bi₁₂O₁₇Cl₂ (BOC) were prepared via a facile solvothermal method using a binary solvent for the photocatalytic degradation of Rhodamine-B (RhB) and Bisphenol-A (BPA). Co₃O₄ nanoparticles (NPs)-decorated BOC (Co₃O₄/BOC) heterostructures were synthesized to further enhance their photocatalytic performance. The microstructural, morphological, and compositional characterization showed that the BOC microspheres are composed of thin (~20 nm thick) nanosheets with a 3D hierarchical morphology and a high surface area. Compared to the pure BOC photocatalyst, the 20-Co₃O₄/BOC heterostructure showed enhanced degradation efficiency of RhB (97.4%) and BPA (88.4%). The radical trapping experiments confirmed that superoxide (^•O₂⁻) radicals played a primary role in the photocatalytic degradation of RhB and BPA. The enhanced photocatalytic performances of the hierarchical Co₃O₄/BOC heterostructure are attributable to the synergetic effects of the highly specific surface area, the extension of light absorption to the more visible light region, and the suppression of photoexcited electron-hole recombination. Our developed nanocomposites are beneficial for the construction of other bismuth-based compounds and their heterostructure for use in high-performance photocatalytic applications.     

Comparison between unsupported mesoporous Co3O4 and supported Co3O4 on mesoporous silica as catalysts for N2O decomposition

Mesoporous Co₃O₄ (meso-Co₃O₄) and Co₃O₄ nanoparticles supported on mesoporous silica SBA-15 (Co/SBA-15) were prepared by hydrothermal synthesis and an impregnation method, respectively. Although the as-prepared meso-Co₃O₄ had mesopores and a higher surface area comparable to that of Co/SBA-15, its catalytic activity for N₂O decomposition was much lower than that of Co₃O₄/SBA-15. The low catalytic activity of meso-Co₃O₄ mainly stems from the drastic decrease of the meso-Co₃O₄ surface area under the reaction condition used. On the other hand, Co/SBA-15 maintained its high surface area and mesopores with the aid of a robust silica support. This finding indicates that Co₃O₄ supported by a support is much more stable and efficient than meso-Co₃O₄ under N₂O decomposition reaction conditions.     

Synthesis of Co3O4/Poly(N‐vinylcarbazole) Core/Shell Composite With Enhanced Optical Property

Co₃O₄/poly(N‐vinylcarbazole) (PNVC) composite with enhanced optical property was synthesized via a simple in situ bulk polymerization of NVC monomers in the presence of Co₃O₄ nanoparticles at an elevated temperature. High‐resolution electron microscopic observations showed that the Co₃O₄ nanoparticles were coated with uniform nanolayer shells of PNVC. Fourier‐transform infrared (FT‐IR) spectroscopy revealed the presence of strong interactions between the PNVC polymer chains with the Co₃O₄ surface in the Co₃O₄/PNVC composite. Raman spectroscopic results supported conclusions based on electron microscopy and FT‐IR spectra. The uniform nanolayer coating of PNVC decreases the inherent bulk conductivity of Co₃O₄, however, significantly increases the fluorescence property of Co₃O₄ nanoparticles.

     

潜在的T2类造影剂Fe3O4@BSA纳米粒子的合成及性能研究

制备了Fe_3O_4@BSA磁性纳米功能材料,包裹在Fe_3O_4纳米粒子表面的牛血清白蛋白(BSA)主要起到分散剂和稳定剂的作用。通过傅里叶变换红外光谱、X射线衍射、透射电子显微镜及热重分析对合成的Fe_3O_4@BSA纳米粒子进行了表征和分析。结果表明,制备的Fe_3O_4@BSA纳米粒子中BSA质量分数约为18.9%。体外成像结果表明,随着Fe_3O_4@BSA纳米粒子浓度的增加,T2成像信号增强,具有明显的阴性造影效果。于0.5 T外磁场下,测得Fe_3O_4@BSA纳米粒子的横向弛豫率(transverse relaxivity,r2)为148.18 L/(mmol·s)。结果表明,Fe_3O_4@BSA纳米粒子能够作为一种潜在的T2类磁共振成像造影剂。     

Preparation of Co3O4/ZrO2(Y2O3) Catalyst and its Enhanced Catalytic Oxidation of CO

Yttria-stabilized zirconia powders were prepared by the sol–gel method coupled with supercritical CO₂ fluid-drying technology, using ZrOCl₂·8H₂O as the precursor, urea as the precipitant, and yttria as the stabilizer. The particles were characterized by X-ray diffraction, TEM and BET. The Co₃O₄/ZrO₂(Y₂O₃) catalysts were prepared by the impregnation method. The content of cobalt was varied from 5 to 12 wt%. The prepared catalysts were calcined at 200–500 °C and the pretreating temperature was varied from 200–400 °C. The performance of CO catalytic oxidation was tested and the catalyst with 8% Co loading, calcined at 200 °C, and with a pretreating temperature of 300 °C, showed the highest catalytic activity. The temperature for 95% CO conversion was as low as 113 °C; and, the catalyst showed both good cycling stability and excellent long-term stability.     

Magnetic Fe3O4@ polydopamine biopolymer: Synthesis,characterization and fabrication of promising nanocomposite

In this work, Functional Fe₃O₄@ polydopamine nanocomposite (Fe₃O₄@PDA) with magnetic response and special surface area were successfully assembled utilizing the strong coordination interactions between these two versatile materials. The morphology and size, crystal structure, specific saturation magnetization, chemical structure, and thermal properties were characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD), vibration magnetometer (VSM), point of zero charge (pH_pzc), Fourier infrared (FT‐IR) and thermogravimetric analysis (TGA). The self‐polymerization of dopamine could be completed within 3 days, and Fe₃O₄ nanoparticles were embedded into PDA polymer. TGA results showed that PDA content of nanocomposite can be up to 51.7 wt% and also showed a significant decrease in the decomposition temperature of PDA from 530 to 270°C in the presence of the Fe₃O₄ nanoparticles. Through TGA analysis the coating thickness was estimated to be about 0.86 nm that it is well coincident with the measured values using TEM images and XRD analysis. At room temperature by vibrating sample magnetometer (VSM), Fe₃O₄ and Fe₃O₄@PDA exhibit superparamagnetic behavior with a saturation moment of 57.87 and 44.7 emu/g, respectively. Furthermore, PZC value reduced for Fe₃O₄@PDA compared with Fe₃O₄ nanoparticles and fell from 6.7 to 3.04. J. VINYL ADDIT. TECHNOL., 25:41–47, 2019. © 2018 Society of Plastics Engineers     

Synthesis of Novel Biocompatible Composite Fe3O4/ZrO2/Chitosan and Its Application for Dye Removal

A novel biocompatible composite Fe₃O₄/ZrO₂/chitosan was synthesized in a simple way and its capacity of dye removal was investigated in this study. The morphology of the material was examined by SEM and TEM and found to be nanosized and spheroidal. Equilibrium adsorption isotherms and dynamic behaviors of the adsorption process were investigated in detail. The material saturated with dye could be regenerated by treatment with strong alkali solution. The composite has high adsorption capacity towards acidic dyes represented by amaranth and tartrazine, and remains intact under conditions that are strongly acidic or alkali. The material has high potential to be applied for the removal of acidic dyes in industrial wastewater in large scale.     

Synthesis of hollow TiO2@g-C3N4/Co3O4 core-shell microspheres for effective photooxidation degradation of tetracycline and MO

Traditional bulk photocatalysts often experience serious charge recombination and poor visible-light capturing, resulting in inefficient photocatalytic activity. However, proper nanostructure design usually helps to increase the activity of composite photocatalysts. Here, hollow TiO₂@g-C₃N₄/Co₃O₄ core-shell microspheres are first reported. The hollow structure of the heterostructured will directionally separate the photogenerated carriers, and the photogenerated holes transferred to the surface will be further captured by Co₃O₄ to achieve an exposed oxidized surface. The novel multi-stage hollow microspheres can simultaneously achieve effective transfer of photogenerated carriers and extended light absorption. Benefiting from these structural and compositional characteristics, the optimized TiO₂@g-C₃N₄/Co₃O₄ nanospheres have excellent photodegradation activity for tetracycline and MO. Under simulated sunlight, the degradation rates of TC (10 mg/L) and MO (25 mg/L) at 60 min are 91.6% and 97.8%, respectively. At the same time, high activity is maintained after multiple cycles of testing. Possible transfer paths for photogenerated carriers have also been proposed. This work will provide more inspiration for the design of multi-stage hollow photocatalytic systems.     

Hierarchical Co3O4@ZnWO4 core/shell nanostructures on nickel foam: Synthesis and electrochemical performance for supercapacitors

To improve the electrochemical properties of Co₃O₄ for supercapacitors application, a hierarchical Co₃O₄@ZnWO₄ core/shell nanowire arrays (NWAs) material is designed and synthesized successfully via a facile two-step hydrothermal method followed by the heat treatment. Co₃O₄@ZnWO₄ NWAs exhibits excellent electrochemical performances with areal capacitance of 4.1 F cm⁻² (1020.1 F g⁻¹) at a current density of 2 mA cm⁻² and extremely good cycling stability (99.7% of the initial capacitance remained even after 3000 cycles). Compared with pure Co₃O₄ electrodes, the results prove that this unique hierarchical hybrid nanostructure and reasonable assembling of two electrochemical pseudocapacitor materials are more advantageous to enhance the electrochemical performance. Considering these remarkable capacitive behaviors, the hierarchical Co₃O₄@ZnWO₄ core/shell NWAs nanostructure electrode can be revealed promising for high-performance supercapacitors.     

Waste catkins-derived graphitic carbon/Co3O4 composites as long-life and high-rate anodes for lithium-ion battery

Upgrading waste re-utilization has been regarded as an important concept to promote the sustainable development of social economy. Herein, waste catkins were used as carbon source and template to prepare graphitic carbon/Co₃O₄ composites through cobalt salt immersion, in-situ carbonization and calcination. The obtained Co₃O₄/C composites inherit the microtubular structure of catkins with ultra-thin tube wall and large tube cavity. Particularly, the sample (Co₃O₄/C-280) calcined at 280 °C in air shows a morphology of the hollow Co₃O₄ spheres (av. 50 nm) evenly embedded on the biocarbon tube. As an anode for lithium-ion battery, such unique structure is more conductive to alleviate volume expansion. As expected, Co₃O₄/C-280 electrode has excellent rate capability at 5 A g⁻¹ and stable long-cycle performance (647.3 mA h g⁻¹, 1800 cycles, 1 A g⁻¹). The presence of pseudo-capacitance behavior plays an important role in improving the capacity of material. The good electrochemical properties of Co₃O₄/C-280 can be ascribed to the synergistic effect of hollow tubular structure and graphitic carbon. Therefore, the strategy of making waste profitable is in line with the theme of green and sustainable development, and provides a reference for improving lithium storage performance of Co₃O₄-based anode materials.     

Preparation of Three-Dimensional Co3O4/graphene Composite for High-Performance Supercapacitors

Here, we developed a simple and efficient route for the preparation of three-dimensional (3D) Co₃O₄-anchored graphene composites using the sacrificial template-assisted method and the subsequent deposition process of Co₃O₄ nanoparticles. As structural guiding materials, polystyrene (PS) spheres provide 3D porous architectures with a high surface area. 3D porous graphene materials serve as conductive supporters for the deposition of Co₃O₄ nanoparticles through precipitation growth. The 3D porous composite structures of Co₃O₄/graphene composites were intensively investigated using scanning electron microscope, transmission electron microscope, and X-ray diffraction. The 3D Co₃O₄/graphene composites show a high specific capacitance of 328?F?g^?1 with efficient and fast charge–discharge process in aqueous 6?M KOH electrolyte. In addition, the composites provide a good cycle lifetime, which retained 98% capacitance retention over 2000 cycles.     

溶胶-凝胶法制备Li4/3Ti5/3O4/Ag复合材料及其表征

采用溶胶-凝胶法制备Li4/3Ti5/3O4/Ag复合材料,通过X射线衍射、扫描电子显微镜、恒电流充放电及交流阻抗等技术检测和分析合成产物的物相、形貌及电化学性质。研究表明,在Li4/3Ti5/3O4中添加Ag后Li4/3Ti5/3O4的Ti—O键没受影响,Li4/3Ti5/3O4/Ag及Li4/3Ti5/3O4的晶格常数非常接近,Ag没有进入Li4/3Ti5/3O4晶格,只是均匀地分散在Li4/3Ti5/3O4颗粒中。与Li4/3Ti5/3O4相比,Li4/3Ti5/3O4/Ag复合材料具有更高的比容量,更高的库仑效率以及更低的极化。添加Ag后对Li4/3Ti5/3O4锂离子扩散系数影响不大。电化学循环过程中,Li4/3Ti5/3O4/Ag的容量损失小于Li4/3Ti5/3O4,且随着充放电倍率的增加两者容量损失差距变大。Ag的添加大大地改善了Li4/3Ti5/3O4的循环性能,尤其是大电流循环性能。     

Co3O4/碳纳米管复合膜的超级电容器性能

采用电泳沉积法在镍片上沉积Co3O4/碳纳米管(CNT)复合膜。利用XRD、SEM和TEM对Co3O4/CNT复合膜进行物性分析,利用循环伏安和恒流充放电测试表征电容性能。研究表明在CNT表面成功包覆了一层Co3O4壳层,形成独特的核/鞘纳米电缆结构。电化学测试表明,Co3O4/CNT复合膜电极具有较好的电容性能,在充放电电流密度为0.5 mA/cm^2时,比电容高达282 F/g;增加电流密度到15 mA/cm2时,比电容为209 F/g,并具有优异的循环稳定性。     

Synthesis of Co3O4 nanotubes and their catalytic applications in CO oxidation

Co₃O₄ nanotubes with the inner of about 8 nm and the length of 200–500 nm were synthesized by oxidizing Co nanowires. Analyses on the structural evolution of the intermediates at different intervals identified that the formation of Co₃O₄ nanotubes followed a nanoscale Kirkendall effect. The outward diffusion of cobalt species was faster than the inward diffusion of oxygen species, resulting in the formation of nanovoids at the initial stage and subsequently the tubular structure. The Co₃O₄ nanotubes showed a higher activity and stability than the spherical nanoparticles in CO oxidation, primarily due of the facile redox feature.     

Hydrothermal Synthesis of Mesoporous Bi2O3/Co3O4 Microsphere and Photocatalytic Degradation of Orange II Dyes by Visible Light

New visible-light-responsive porous Bi₂O₃/Co₃O₄ microspheres have been successfully synthesized by hydrothermal method in ethylene glycol (EG) accompanied with the addition of polyethyleneglycol (PEG) and sodium acetate. PEG can enter into the initial nuclei because of the similar structure and composition with EG, resulting in the formation of hollow porous structures. The specific surface area incorporating bismuth and cobalt oxides is enlarged by comparing with their pristine forms. According to the photocatalysis results, Bi₂O₃/Co₃O₄ composite microsphere is more effective to degrade Orange II dye than pure Bi₂O₃ photocatalyst by better utilizing visible light activities.     

Electrochemical preparation and properties of nanostructured Co3O4 as supercapacitor material

Nanostructured Co₃O₄ was prepared via a simple two-step process: cathodic electrodeposition of cobalt hydroxide from additive free nitrate bath and then heat treatment at 400 °C for 3 h. The prepared oxide product was characterized by powder X-ray diffraction, infrared spectroscopy, surface area measurement, scanning electron microscopy, and transmission electron microscopy. Morphological characterization showed that the oxide product was composed of porous nanoplates, and BET measurement displayed that the oxide plates have the average pore diameter and the surface area of 4.75 nm and 208.5 m² g⁻¹, respectively. The supercapacitive performance of the nanoplates was evaluated using cyclic voltammetry and charge–discharge tests. A specific capacitance as high as 393.6 F g⁻¹ at the constant current density of 1 A g⁻¹ and an excellent capacity retention (96.5% after 500 charge–discharge cycles) was obtained. These results indicate that Co₃O₄ nanoplates can be recognized as high-performance electrode materials.