Laser‑Induced and MOF‑Derived Metal Oxide/Carbon Composite for Synergistically Improved Ethanol Sensing at Room temperature

Advancements in sensor technology have significantly enhanced atmospheric monitoring.Notably,metal oxide and carbon(MO_(x)/C)hybrids have gained attention for their exceptional sensitivity and room-temperature sensing performance.However,previous methods of synthesizing MO_(x)/C composites suffer from problems,including inhomogeneity,aggregation,and challenges in micropatterning.Herein,we introduce a refined method that employs a metal–organic framework(MOF)as a precursor combined with direct laser writing.The inherent structure of MOFs ensures a uniform distribution of metal ions and organic linkers,yielding homogeneous MO_(x)/C structures.The laser processing facilitates precise micropatterning(<2μm,comparable to typical photolithography)of the MO_(x)/C crystals.The optimized MOF-derived MO_(x)/C sensor rapidly detected ethanol gas even at room temperature(105 and 18 s for response and recovery,respectively),with a broad range of sensing performance from 170 to 3,400 ppm and a high response value of up to 3,500%.Additionally,this sensor exhibited enhanced stability and thermal resilience compared to previous MOF-based counterparts.This research opens up promising avenues for practical applications in MOF-derived sensing devices.

An effective strategy of constructing multi-metallic oxides of ZnO/ CoNiO_(2)/CoO/C microflowers for improved supercapacitive performance

In this work,a new ZnO/CoNiO_(2)/CoO/C metal oxides composite is prepared by cost-effective hydrothermal method coupled with annealing process under N_(2) atmosphere.Notably,the oxidation-defect annealing environment is conducive to both morphology and component of the composite,which flower-like ZnO/CoNiO_(2)/CoO/C is obtained.Benefited from good chemical stability of ZnO,high energy capacity of CoNiO_(2) and CoO and good conductivity of C,the as-prepared sample shows promising electrochemical behavior,including the specific capacity of 1435 C·g^(-1) at 1 A·g^(-1),capacity retention of 87.3%at 20 A·g^(-1),and cycling stability of 90.5%for 3000 cycles at 5 A·g^(-1),respectively.Furthermore,the prepared ZnO/CoNiO_(2)/CoO/C/NF//AC aqueous hybrid supercapacitors device delivers the best specific energy of 55.9 W·h·kg^(-1) at 850 W·kg^(-1).The results reflect that the as-prepared ZnO/CoNiO_(2)/CoO/C microflowers are considered as high performance electrode materials for supercapacitor,and the strategy mentioned in this paper is benefit to prepare mixed metal oxides composite for energy conversion and storage.

Application of CO_2-TPD in the Synthesis of Composite Oxides from Metal-Organic Precursors

CO2-TPD was demonstrated an effective way to investigate the phase formation during pyrolysis for the preparation of composite oxides using metal-organic molecules as precursors.Based on the CO2-TPD results, it was found that calcination condition had deep effect on the carbonate formation and the minimum firing temperature to acquire pure phase composite oxide.An optimized calcination schedule was then developed.

Influence of nano-Al_2O_3-reinforced oxide-dispersion-strengthened Cu on the mechanical and tribological properties of Cu-based composites

The mechanical and tribological properties of Cu-based powder metallurgy （P/M） friction composites containing 10wt%-50wt% oxide-dispersion-strengthened （ODS） Cu reinforced with nano-Al2O3 were investigated. Additionally, the friction and wear behaviors as well as the wear mechanism of the Cu-based composites were characterized by scanning electron microscopy （SEM） in conjunction with energy-dispersive X-ray spectroscopy （EDS） elemental mapping. The results indicated that the Cu-based friction composite containing 30wt% ODS Cu exhibited the highest hardness and shear strength. The average and instantaneous friction coefficient curves of this sample, when operated in a high-speed train at a speed of 300 km/h, were similar to those of a commercial disc brake pad produced by Knorr-Bremse AG （Germany）. Additionally, the lowest linear wear loss of the obtained samples was （0.008 ± 0.001） mm per time per face, which is much lower than that of the Knorr-Bremse pad （（0.01 ± 0.001） mm）. The excellent performance of the developed pad is a consequence of the formation of a dense oxide composite layer and its close combination with the pad body.

Preparation of SiC_p/Al_2O_3-Al Composites by Directed Metal Oxidation

SiCp/Al2O3-Al composites were synthesized by means of direct metal oxidation method. The composition and microstructures of the composites were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM） and metallurgical microscope. The effects of technical parameters on the properties of the product were analyzed. The results indicate that the composite possesses a dense microstructure, composed of three interpenetrated phases. Of them, SiO2 layer prohibits the powdering of the composites; Mg promotes the wetting and infiltration of the system and Si restricts the interfacial reaction while improving the wetting ability between reinforcement and matrix.

Preparation of Polymer-Mineral Nanocomposites Based on Vinyl Monomers and Dispersed Inorganic Oxides

The polymer-mineral composites were synthesized using vinyl monomers styrene, methyl acrylate, and butyl acrylate with nano dispersed oxides Fe2O3, Cr2O3, V2O5 and SiO2 in the presence of benzoyl peroxide and other peroxide initiators. Benzoyl peroxide adsorption on Fe2O3, Cr2O3, and V2O5 surfaces was studied. The adsorption parameters were found: adsorption-desorption equilibrium constants, maximum adsorption, and the area occupied by the molecule benzoyl peroxide on the surface of the adsorbent. The molecular weights of the polymers in the composites and the degree of grafting of the macromolecules of the polymer to the surface of oxides were studied. It has been found that the surface of the dispersed oxides influences the rate of thermal decomposition of the peroxide initiators and the polymerization parameters of the vinyl monomers.

ZnO-Embedded Expanded Graphite Composite Anodes with Controlled Charge Storage Mechanism Enabling Operation of Lithium-Ion Batteries at Ultra-Low Temperatures

As lithium(Li)-ion batteries expand their applications,operating over a wide temperature range becomes increasingly important.However,the lowtemperature performance of conventional graphite anodes is severely hampered by the poor diffusion kinetics of Li ions(Li^(+)).Here,zinc oxide(ZnO) nanoparticles are incorporated into the expanded graphite to improve Li^(+)diffusion kinetics,resulting in a significant improvement in lowtemperature performance.The ZnO-embedded expanded graphite anodes are investigated with different amounts of ZnO to establish the structurecharge storage mechanism-performance relationship with a focus on lowtemperature applications.Electrochemical analysis reveals that the ZnOembedded expanded graphite anode with nano-sized ZnO maintains a large portion of the diffusion-controlled charge storage mechanism at an ultra-low temperature of-50℃ Due to this significantly enhanced Li^(+)diffusion rate,a full cell with the ZnO-embedded expanded graphite anode and a LiNi_(0.88)Co_(0.09)Al_(0.03)O_(2)cathode delivers high capacities of 176 mAh g^(-1)at20℃ and 86 mAh g^(-1)at-50℃ at a high rate of 1 C.The outstanding low-temperature performance of the composite anode by improving the Li^(+)diffusion kinetics provides important scientific insights into the fundamental design principles of anodes for low-temperature Li-ion battery operation.

Thermotics Study of the Semimetallic Nylon1010 Composite

Thermal expansion characteristics of semimetal nylon composites (nylon 1010 incorporated with metal oxides) were analyzed with thermal expansion instrument. The changes of composite weight after being heated and the heat absorption and release of the composites were analyzed by carrying out TG-DSC experiments. Experimental results show that the average thermal expansion coefficient of the composites rises as the average diameter of the metal oxides decrease from room temperature to 160 ℃. Thermal dynamics and physical properties of the nylon composites change with the addition of the oxides; the crystallization temperature rises from 180 ℃ of pure nylon to 190 ℃ (maximum) and the melting point of the oxide composites also increases continuously with the addition of the oxides. The water content of the oxide/nylon composite is related to the kind and content of the oxide. The water content reaches its maximum when the content of oxide is 10%, and the 10% Al2O3/nylon composite has a water absorption ratio up to 1%.

High-temperature oxidation behavior of CeO_2-SiO_2/Ni-W-P composites

Ni-W-P matrix composites containing CeO2 and SiO2 nano-particles were prepared on common carbon steel surface by means of pulse electrodeposition,and the high-temperature oxidation behavior was investigated.The results show that when the oxidation time is controlled in 1 h,oxidation kinetics curve between oxidation mass gain rate and oxidation temperature of CeO2-SiO2/Ni-W-P composites accords with the index increasing law.When the oxidation temperature is controlled at 300℃,the kinetics curve between oxidation mass gain rate and oxidation time accords with the linear increasing law.The composites as-deposited are in the amorphous state and turn into the crystal state at 400℃.The microstructures of oxidation film on the composites will change from the compact state to the loose state with increasing oxidation temperature to 800℃.They are still continuous and compact,and there are no crackle,strip and falling-out.CeO2 and SiO2 nano-particles co-deposited into Ni-W-P alloy can improve the high-temperature oxidation resistance.

Anisotropic Thermally-Accessible Lattice Distortion of a Cu（ll）-Cr（VI） Complex Bimetallic Oxide by Adsorbing a Chiral One-Dimensional Cu（ll）-Cr（VI） Coordination Polymer

The authors have prepared and characterized a chiral one-dimensional Cu（II）-Cr（VI） coordination polymer, [CuL2][Cr207] （L = （IR, 2R）-diaminocyclohexane）, which exhibited intense d-d bands as well as charge transfer bands in the solid state electronic and CD spectra. Thermally-accessible lattice distortion was observed along the crystallographic a axis, which corresponded to Jahn-Teller distortion of Cu（II） chromophores. After firing [CuL2][Cr207], they could obtain a Cu（II）-Cr（VI） complex bimetallic oxide showing ferromagnetism and isotropic thermally-accessible lattice distortion. Preparation of composite materials of the coordination polymers and a complex bimetallic oxide could be confirmed by IR spectra and magnetic properties. It should be noted that the complex bimetallic oxide as the composite exhibited anisotropic thermally-accessible lattice distortion by adsorption of the chiral one-dimensional coordination polymer.

A review on transition metal oxides based photocatalysts for degradation of synthetic organic pollutants

This review provides insight into the current research trend in transition metal oxides(TMOs)-based photocatalysis in removing the organic colouring matters from water.For easy understanding,the research progress has been presented in four generations according to the catalyst composition and mode of application,viz:single component TMOs(the firstgeneration),doped TMOs/binary TMOs/doped binary TMOs(the second-generation),inactive/active support-immobilized TMOs(the third-generation),and ternary/quaternary compositions(the fourth-generation).The first two generations represent suspended catalysts,the third generation is supported catalysts,and the fourth generation can be suspended or supported.The review provides an elaborated comparison between suspended and supported catalysts,their general/specific requirements,key factors controlling degradation,and the methodologies for performance evaluation.All the plausible fundamental and advanced dye degradation mechanisms involved in each generation of catalysts were demonstrated.The existing challenges in TMOs-based photocatalysis and how the researchers approach the hitch to resolve it effectively are discussed.Future research trends are also presented.

Hybrid CuO-Co_(3)O_(4)nanosphere/RGO sandwiched composites as anode materials for lithium-ion batteries

Hybrid CuO-Co_(3)O_(4)nanosphere building blocks have been embedded between the layered nanosheets of reduced graphene oxides with a three dimensional(3D)hybrid architecture(CuO-Co_(3)O_(4)-RGO),which are successfully applied as enhanced anodes for lithium-ion batteries(LIBs).The CuO-Co_(3)O_(4)-RGO sandwiched nanostructures exhibit a reversible capacity of~847 mA·h·g^(-1)after 200 cycles’cycling at 100 mA·g^(-1)with a capacity retention of 79%.The CuO-Co_(3)O_(4)-RGO compounds show superior electrochemical properties than the comparative CuO-Co_(3)O_(4),Co_(3)O_(4)and CuO anodes,which may be ascribed to the following reasons:the hybridizing multicomponent can probably give the complementary advantages;the mutual benefit of uniformly distributing nanospheres across the layered RGO nanosheets can avoid the agglomeration of both the RGO nanosheets and the CuO-Co_(3)O_(4) nanospheres;the 3D storage structure as well as the graphene wrapped composite could enhance the electrical conductivity and reduce volume expansion effect associated with the discharge-charge process.

Bacterial Cellulose Templated p-Co3O4/n-ZnO Nanocomposite with Excellent VOCs Response Performance

In this work,p-type Co3O4 decorated n-type ZnO(Co3O4/ZnO)nanocomposite was designed with the assistance of bacterial cellulose template.Phase composition,morphology and element distribution were investigated by XRD,SEM,HRTEM,EDS mapping and XPS.Volatile organic compounds(VOCs)sensing measurements indicated a noticeable improvement of response and decrease of working temperature for Co3O4/ZnO sensor,in comparison with pure ZnO,i.e.,the response towards 100 ppm acetone was 63.7(at a low working temperature of 180℃),which was 26 times higher than pure ZnO(response of 2.3 at 240℃).Excellent VOCs response characteristics could be ascribed to increased surface oxygen vacancy concentration(revealed by defect characterizations),catalytic activity of Co3O4 and the special p-n heterojunction structure,and bacterial cellulose provides a facile template for designing diverse functional heterojunctions for VOCs detection and other applications.

Utilization of Various Analogy of Synthetic Nanoporous Zeolites and Composite of Zeolites for Decontamination/Detoxification of CWA Simulants—An Updated Review

In this review, we summaries the past few year work on the chemistry of CWA’s and their simulants on various heterogeneous surfaces of zeolites, composites of zeolites and doped zeolite with transition metal oxides. This review elaborates an updated literature overview on the degradation of CWA’s and its simulants. The data written in this review were collected from the peer-reviewed national and international literature.

Preparation of ultrafine Sb2O5 composite powder

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Cu-Ce-Al复合金属氧化物催化H_(2)O_(2)高效氧化降解苯酚

本文采用共沉淀法制备了Cu-Ce-Al复合金属氧化物,实现了苯酚污染物的高效氧化降解。利用XRD、BET、SEM等方法对材料进行了表征;考察了不同pH、温度、催化剂用量、H_(2)O_(2)用量对苯酚(470 mg·L^(-1))降解率的影响。结果表明,在pH=3~6范围内,苯酚可实现高效降解:pH=4、温度50℃、反应40 min,苯酚完全降解,COD去除率高达85.37%。催化剂重复使用三次,苯酚降解率依然在99%以上,说明Cu-Ce-Al复合金属氧化物具有较高的催化活性和良好的稳定性。

Spray Pyrolysis Deposition of Single and Mixed Oxide Thin Films

The influence of processing parameters is investigated on the structural characteristics of single and mixed oxides produced by spray pyrolysis technique. The films were synthesized by spraying precursor solutions through a noz-zle onto a heated alumina substrate. The precursor consisted separately of aqueous solutions of tin chloride for SnO2 and zinc chloride for ZnO for single oxide cases, and aqueous solutions of tin chloride and indium nitrate for SnO2 + In2O3 and zinc chloride and indium nitrate solutions for ZnO + In2O3 for mixed oxide cases. The substrate temperature was varied accordingly for each single and mixed case. The films produced were characterized by X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy. The results indicate that a non-homogenous film is formed at low temperature for both single oxides considered. The temperature has significant effect on the composition of the synthesized films of both single oxides below 450℃. The results for mixed oxides show that the best homogeneous films are obtained for 80 wt% ZnO + 20 wt% In2O3, and 80 wt% SnO2 + 20 wt% In2O3.

树枝状磺化聚醚砜纤维基复合固态电解质的制备及其性能

为解决应用于全固态锂金属电池中固态有机电解质离子电导率较低和力学性能较弱的问题,采用静电纺丝技术制备了树枝状磺化聚醚砜(SPES)纳米纤维膜,将其与聚氧化乙烯(PEO)结合制备复合固态电解质,并应用于全固态锂金属电池中。探讨了纺丝工艺对纳米纤维形貌的影响,在最佳的静电纺丝工艺参数下,研究了SPES纳米纤维膜对复合固态电解质结晶度、离子电导率、力学性能以及电化学性能的影响。结果表明:在四丁基六氟磷酸铵质量分数为2%,静电纺丝电压为30 kV,接收距离为15 cm时,制备的树枝状SPES纳米纤维膜具有最好的形貌,将PEO浇筑在该纳米纤维膜上获得的复合固态电解质其离子电导率为8.13×10^(-5)S/cm(30℃),断裂强度为5.1 MPa,且可使对称电池在0.1 mA·h/cm^(2)下稳定循环198 h,使LiFePO_(4)/Li电池在循环400圈后仍保持着128.6 mA·h/g的放电比容量;SPES纳米纤维膜因破坏PEO的结晶区且能构成三维离子传输路径,不仅提高了复合固态电解质的离子电导率,还使复合固态电解质具有优异的力学强度,可满足高性能全固态锂金属电池的应用需求。

金属氧化物基生物炭复合材料在污水处理领域中的应用现状

生物炭是生物质在缺氧条件下热解产生的一种富含碳固体物质,特点为疏松多孔、比表面积大且表面富含酚羟基、羧基和氨基等多种官能团。同时,生物炭是一种廉价易得、性能优良的吸附材料,因其环境友好、来源广泛,在污水处理领域具有广泛应用。分析了生物炭对水中污染物的吸附机理,重点阐述了TiO_(2)、磁性氧化铁、MnO_(2)以及其他氧化物等金属氧化物基生物炭复合材料在污水处理领域中的应用现状、循环利用以及再生性能,最后展望了金属氧化物基生物炭复合材料的发展前景。