PVP-assisted laser ablation growth of Ag nanocubes anchored on reduced graphene oxide(rGO) for efficient photocatalytic CO_2 reduction

Metallic nanoparticles loaded graphene nanocomposites have been widely studied for various scientific and technological applications. In this study, a facile method was reported to realize a straightforward growth of shape and size-controllable of metallic nanoparticles, and the subsequent hybridization with graphene in solution by strategically coupling wet-chemical route and laser ablation. By mixing graphene oxide(GO) with a tunable concentration level of polyvinylpyrrolidone(PVP) in aqueous solution, Ag nanocubes with a face-centered cubic crystal structure were generated by pulsed laser ablation and then mounted on GO nanosheets with the assistance of PVP. The preferential adsorption of PVP to Ag(100) crystal face led to the production of Ag nanocubes with exposed(100) facet. The result showed that the morphological yield of spherical particles decreased with the increase in PVP concentration. X-ray diffraction(XRD) and UV–visible spectroscopy analyses confirmed that GO was partially reduced. In the reduction of CO_2 gas, the photocatalytic conversion rate could achieve 133.1 μmol g~(-1) h~(-1) in 6 hrs for cubic Ag-loaded reduced GO composites.     

TiO2对含铬高钛熔分渣熔化性能和黏度的影响

A study on the melting and viscosity properties of the chromium-containing high-titanium melting slag (CaO–SiO₂–MgO–Al₂O₃–TiO₂–Cr₂O₃) with TiO₂ contents ranging from 38.63wt% to 42.63wt% was conducted. The melting properties were investigated with a melting-point apparatus, and viscosity was measured using the rotating cylinder method. The FactSage 7.1 software and X-ray diffraction, in combination with scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS), were used to characterize the phase equilibrium and microstructure of chromium-containing high-titanium melting slags. The results indicated that an increase in the TiO₂ content led to a decrease in the viscosity of the chromium-containing high-titanium melting slag. In addition, the softening temperature, hemispheric temperature, and flowing temperature decreased with increasing TiO₂ content. The amount of crystallized anosovite and sphene phases gradually increased with increasing TiO₂ content, whereas the amount of perovskite phase decreased. SEM observations revealed that the distribution of the anosovite phase was dominantly influenced by TiO₂.     

TiB2和Al3Ti对近共晶Al?12.6Si合金组织、力学性能和断裂行为的影响

A near eutectic Al?12.6Si alloy was developed with 0.0wt%, 2.0wt%, 4.0wt%, and 6.0wt% Al?5Ti?1B master alloy. The microstructural morphology, hardness, tensile strength, elongation, and fracture behaviour of the alloys were studied. The unmodified Al?12.6Si alloy has an irregular needle and plate-like eutectic silicon (E_Si) and coarse polygonal primary silicon (P_Si) particles in the matrix-like α-Al phase. The P_Si, E_Si, and α-Al morphology and volume fraction were changed due to the addition of the Al?5Ti?1B master alloy. The hardness, UTS, and elongation improved due to the microstructural modification. Nano-sized in-situ Al₃Ti particles and ex-situ TiB₂ particles caused the microstructural modification. The fracture images of the developed alloys exhibit a ductile and brittle mode of fracture at the same time. The Al?5Ti?1B modified alloys have a more ductile mode of fracture and more dimples compared to the unmodified alloy.     

单斜相SrAl2Si2O8陶瓷的烧结及其对Sr的固化

Monoclinic SrAl₂Si₂O₈ ceramics for Sr immobilization were prepared by a liquid-phase sintering method. The sintering temperature, mineral phase composition, microstructure, flexural strength, bulk density, and Sr ion leaching characteristics of the SrAl₂Si₂O₈ ceramics were investigated. A crystalline monoclinic SrAl₂Si₂O₈ phase formed through liquid-phase sintering at 1223 K. The introduction of four flux agents (B₂O₃, CaO·2B₂O₃, SrO·2B₂O₃, and BaO·2B₂O₃) to the SrAl₂Si₂O₈ ceramics not only reduced the densification temperature and decreased the volatilization of Sr during high-temperature sintering but also impacted the mechanical properties of the ceramics. Product consistency tests showed that the leaching concentration of Sr ions in the sample with flux agent B₂O₃ was the lowest, whereas that of Sr ions in the sample with flux agent BaO·2B₂O₃ was the highest. These results show that the leaching concentration of Sr ions depends largely on the amorphous phase in the ceramics. Meanwhile, the formation of mineral analog ceramics containing Sr is an important factor to improve Sr immobilization.     

Biodegradable starch/poly (vinyl alcohol) film reinforced with titanium dioxide nanoparticles

Biodegradable starch/poly (vinyl alcohol)/nano-titanium dioxide (ST/PVA/nano-TiO₂) nanocomposite films were prepared via a solution casting method. Their biodegradability, mechanical properties, and thermal properties were also studied in this paper. A general full factorial experimental approach was used to determine effective parameters on the mechanical properties of the prepared films. ST/PVA/TiO₂ nanocomposites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results of mechanical analysis show that ST/PVA films with higher contents of PVA have much better mechanical properties. In thermal analysis, it is found that the addition of TiO₂ nanoparticles improves the thermal stability of the films. SEM micrographs, taken from the fracture surface of samples, illustrate that the addition of PVA makes the film softer and more flexible. The results of soil burial biodegradation indicate that the biodegradability of ST/PVA/TiO₂ films strongly depends on the starch proportion in the film matrix. The degradation rate is increased by the addition of starch in the films.     

强耦合非晶态Sb2S3球与碳纳米管中的钠离子和锂离子存储

A facile one-step strategy involving the reaction of antimony chloride with thioacetamide at room temperature is successfully developed for the synthesis of strongly coupled amorphous Sb₂S₃ spheres and carbon nanotubes (CNTs). Benefiting from the unique amorphous structure and its strongly coupled effect with the conductive network of CNTs, this hybrid electrode (Sb₂S₃@CNTs) exhibits remarkable sodium and lithium storage properties with high capacity, good cyclability, and prominent rate capability. For sodium storage, a high capacity of 814 mAh·g?1 at 50 mA·g?1 is delivered by the electrode, and a capacity of 732 mAh·g?1 can still be obtained after 110 cycles. Even up to 2000 mA·g?1, a specific capacity of 584 mAh·g?1 can be achieved. For lithium storage, the electrode exhibits high capacities of 1136 and 704 mAh·g?1 at 100 and 2000 mA·g?1, respectively. Moreover, the cell holds a capacity of 1104 mAh·g?1 under 100 mA·g?1 over 110 cycles. Simple preparation and remarkable electrochemical properties make the Sb₂S₃@CNTs electrode a promising anode for both sodium-ion (SIBs) and lithium-ion batteries (LIBs).     

硫酸溶液中IrO2–ZrO2二元氧化物涂层的电化学行为及耐蚀性

In this study, we prepared Ti/IrO₂–ZrO₂ electrodes with different ZrO₂ contents using zirconium-n-butoxide (C₁₆H₃₆O₄Zr) and chloroiridic acid (H₂IrCl₆) via a sol–gel route. To explore the effect of ZrO₂ content on the surface properties and electrochemical behavior of electrodes, we performed physical characterizations and electrochemical measurements. The obtained results revealed that the binary oxide coating was composed of rutile IrO₂, amorphous ZrO₂, and an IrO₂–ZrO₂ solid solution. The IrO₂–ZrO₂ binary oxide coatings exhibited cracked structures with flat regions. A slight incorporation of ZrO₂ promoted the crystallization of the active component IrO₂. However, the crystallization of IrO₂ was hindered when the added ZrO₂ content was greater than 30at%. The appropriate incorporation of ZrO₂ enhanced the electrocatalytic performance of the pure IrO₂ coating. The Ti/70at%IrO₂–30at%ZrO₂ electrode, with its large active surface area, improved electrocatalytic activity, long service lifetime, and especially, lower cost, is the most effective for promoting oxygen evolution in sulfuric acid solution.     

Experimental study on sulfur removal from ladle furnace refining slag in hot state by blowing air

In view of the present problem of sulfur enrichment in the metallurgical recycling process of ladle furnace (LF) refining slag, a simple and efficient method of removing sulfur from this slag was proposed. The proposed method is compatible with current steelmaking processes. Sulfur removal from LF refining slag for SPHC steel (manufactured at a certain steel plant in China) by blowing air in the hot state was studied by using hot-state experiments in a laboratory. The FactSage software, a carbon/sulfur analyzer, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to test and analyze the sulfur removal effect and to investigate factors influencing sulfur removal rate. The results show that sulfur ions in LF refining slag can be oxidized into SO₂ by O₂ at high temperature by blowing air into molten slag; SO₂ production was observed to reach a maximum with a small amount of blown O₂ when the temperature exceeded 1350℃. At 1370℃ and 1400℃, experimental LF refining slag is in the liquid state and exhibits good fluidity; under these conditions, the sulfur removal effect by blowing air is greater than 90wt% after 60 min. High temperature and large air flow rate are beneficial for removing sulfur from LF refining slag; compared with air flow rate, temperature has a greater strongly influences on the sulfur removal.     

Effect of TiO<Subscript>2</Subscript> on the viscosity and structure of low-fluoride slag used for electroslag remelting of Ti-containing steels

The viscosity of CaF₂-CaO-Al₂O₃-MgO-(TiO₂) slag was measured using a rotating crucible viscometer. Raman spectroscopy analysis was performed to correlate the viscosity to slag structure. The viscosity of the slag was found to decrease with increasing TiO₂ content in the slag from 0 to 9.73wt%. The activation energy decreased from 95.16 kJ/mol to 79.40 kJ/mol with increasing TiO₂ content in the slag. The introduction of TiO₂ into the slag played a destructive role in Al-O-Al structural units and Q4 units by forming simpler structural units of Q2 and Ti₂O₆4- chain. The amount of Al-O-Al significantly decreased with increasing TiO₂ content. The relative fraction of Q4 units in the[AlO₄]5--tetrahedral units shows a decreasing trend, whereas the relative fraction of Q2 units and Ti₂O₆4- chain increases with increasing TiO₂ content accordingly. Consequently, the polymerization degree of the slag decreases with increasing TiO₂ content. The variation in slag structure is consistent with the change in measured viscosity.     

Effects of MgO and TiO<Subscript>2</Subscript> on the viscous behaviors and phase compositions of titanium-bearing slag

The effects of MgO and TiO₂ on the viscosity, activation energy for viscous flow, and break-point temperature of titanium-bearing slag were studied. The correlation between viscosity and slag structure was analyzed by Fourier transform infrared (FTIR) spectroscopy. Subsequently, main phases in the slag and their content changes were investigated by X-ray diffraction and Factsage 6.4 software package. The results show that the viscosity decreases when the MgO content increases from 10.00wt% to 14.00wt%. Moreover, the break-point temperature increases, and the activation energy for viscous flow initially increases and subsequently decreases. In addition, with increasing TiO₂ content from 5.00wt% to 9.00wt%, the viscosity decreases, and the break-point temperature and activation energy for viscous flow initially decrease and subsequently increase. FTIR analyses reveal that the polymerization degree of complex viscous units in titanium-bearing slag decreases with increasing MgO and TiO₂ contents. The mechanism of viscosity variation was elucidated. The basic phase in experimental slags is melilite. Besides, as the MgO content increases, the amount of magnesia–alumina spinel in the slag increases. Similarly, the sum of pyroxene and perovskite phases in the slag increases with increasing TiO₂ content.     

超临界乙醇制备TiO2/石墨烯纳米复合材料及其表征

以氧化石墨为载体、钛酸异丙酯为前驱体,利用超临界乙醇的超临界性能和还原性,制得了晶型完善的锐钛矿TiO2/石墨烯纳米复合材料.通过红外光谱（FTIR）、X射线光电子能谱（XPS）对采用Hummers法制得的氧化石墨（GO）进行表征;同时利用透射电子显微镜（TEM）、X射线衍射仪（XRD）对TiO2/石墨烯纳米复合材料进行研究.结果表明：成功制得了氧化石墨（GO）和晶型完善的锐钛矿TiO2/石墨烯纳米复合材料,并且发现二氧化钛在石墨烯纳米片层上呈现为有规则的颗粒,分散均匀,平均粒径为8.24 nm.     

A ternary TiO2/WO3/graphene nanocomposite adsorbent: facile preparation and efficient removal of Rhodamine B

Ternary TiO₂/WO₃/graphene (TWG) nanocomposites were prepared by a facile salt-ultrasonic assisted hydrothermal method. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption. Both anatase TiO₂ and orthorhombic WO₃ formed in the nanocomposites, along with a highly disordered overlay of individual graphene nanosheets. Polyhedral and spherical TiO₂ and WO₃ nanoparticles of uniform size 10–30 nm were densely anchored to the graphene sheets. The maximum specific surface area of the products was 144.59 m²·g^?1. The products showed clear abilities for the removal of Rhodamine B in the absence of illumination. Furthermore, the adsorption activity of the products exhibited only a slight decrease after three successive cycles. The results demonstrate that the ternary nanocomposites could be used as a high-efficiency adsorbent for the removal of environmental contaminants.     

聚丙烯酸固载纳米TiO2复合材料的制备及其光催化性能

采用改进的溶胶-凝胶法制备了水溶性TiO₂干凝胶,利用交联聚丙烯酸（PAA）强吸水性和三维网状结构特点,将TiO₂溶胶粒子固载到聚丙烯酸高分子链上,经过水热处理原位生长制备PAA/TiO₂纳米复合材料。通过拉曼光谱（Raman）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）等测试手段研究PAA/TiO₂纳米复合材料的结构特征,以甲基橙为模型污染物研究了PAA/TiO₂纳米复合材料的光催化性能。结果表明,纳米TiO2粒子被固载到PAA高分子链上,PAA吸水膨胀后扩展至整个反应空间,有效地增加了纳米TiO₂与有机污染物的接触面积,大大提高了光催化降解的效率。     

机械合金化法制备的Cu/SiC纳米复合材料的组织、热性能和力学性能评估

Nano-sized silicon carbide (SiC: 0wt%, 1wt%, 2wt%, 4wt%, and 8wt%) reinforced copper (Cu) matrix nanocomposites were manufactured, pressed, and sintered at 775 and 875°C in an argon atmosphere. X-ray diffraction (XRD) and scanning electron microscopy were performed to characterize the microstructural evolution. The density, thermal expansion, mechanical, and electrical properties were studied. XRD analyses showed that with increasing SiC content, the microstrain and dislocation density increased, while the crystal size decreased. The coefficient of thermal expansion (CTE) of the nanocomposites was less than that of the Cu matrix. The improvement in the CTE with increasing sintering temperature may be because of densification of the microstructure. Moreover, the mechanical properties of these nanocomposites showed noticeable enhancements with the addition of SiC and sintering temperatures, where the microhardness and apparent strengthening efficiency of nanocomposites containing 8wt% SiC and sintered at 875°C were 958.7 MPa and 1.07 vol%?1, respectively. The electrical conductivity of the sample slightly decreased with additional SiC and increased with sintering temperature. The prepared Cu/SiC nanocomposites possessed good electrical conductivity, high thermal stability, and excellent mechanical properties.     

钒酸铋/二氧化钛--石墨烯宽光谱复合光催化剂的制备及性能

通过溶剂热法制备了具有可见光光催化活性的BiVO4/TiO2-石墨烯复合光催化剂。利用X射线粉末衍射、透射电子显微镜、紫外-可见漫反射光谱和荧光发射光谱对样品进行表征,复合光催化剂的催化活性以模拟太阳光条件下降解水溶液中亚甲基蓝来评价。结果表明：BiVO4/TiO2-石墨烯复合光催化剂在530~800 nm的可见光范围具有很强的吸收峰。石墨烯的引入不仅拓宽了光谱响应范围,而且使得BiVO4和TiO2粒子均匀地分散在石墨烯薄片上,能快速捕获并迁移电子,有效地提高了光生载流子的分离效率,从而提高其光催化活性。     

TiO2纳米刺球制备和表征

采用溶胶-凝胶法制备出球形TiO2纳米粒子,通过离心的方法将TiO2纳米粒子从乙醇中转移到水中.在60℃下,将分散剂聚乙烯吡咯烷酮(PVP)和刻蚀剂NaBH4加入到TiO2纳米粒子水分散体系中,经61h的恒温刻蚀反应,制备出TiO2纳米刺球.此外,该刻蚀方法同样被应用于Au@SiO2@TiO2纳米刺球的制备.用扫描电子显微镜(SEM)、动态光散射(DLS)、透射电镜(TEM)及X射线衍射实验(XRD)等方法对TiO2纳米粒子和Au@SiO2@TiO2纳米粒子及其纳米刺球进行表征,进而探索NaBH4刻蚀TiO2的机理.该刻蚀方法所需的设备和实验步骤相对简单,反应条件温和可控,较易实现大批量的TiO2纳米刺球的合成并且也适用于外壳层为TiO2的复合核壳结构纳米刺球的制备.     

不同条件下铱负载催化剂性能的比较研究

To discuss the potential role of iridium (Ir) nanoparticles loaded under atmospheric and high pressures, we prepared a series of catalysts with the same active phase but different contents of 10wt%, 20wt%, and 30wt% on gamma-alumina for decomposition of hydrazine. Under atmospheric pressure, the performance of the catalyst was better when 30wt% of the Ir nanoparticles was used with chelating agent that had greater selectivity of approximately 27%. The increase in the reaction rate from 175 to 220 h?1 at higher Ir loading (30wt%) was due to a good dispersion of high-number active phases rather than an agglomeration surface. As a satisfactory result of this investigation at high pressure, Ir catalysts with different weight percentages showed the same stability against crushing and activity with a characteristic velocity of approximately 1300 m/s.     

CuInS2／石墨烯混合物的合成及其在太阳能电池中的应用

在不同的溶剂中通过温和的溶剂热法,成功地合成 CuInS2纳米晶体。这些合成好的 CuInS2粉末被 X光衍射表征后,又作为对电极被组装成染料敏化太阳能电池。通过检测可以发现乙二醇是合成 CuInS2过程中最佳的溶液。这主要表现在用乙二醇合成的 CuInS2作为电池对电极时的转化率可以达到5·49％,这个值要比用其他溶液合成的 CuInS2转化率高。然后,将在乙二醇溶剂中合成的 CuInS2粉末与石墨烯的氧化物混合形成 CuInS2纳米晶体／石墨烯纳米复合材料,这种材料可以提高 CuInS2在染料敏化太阳能电池方面的性能。通过透射电子显微镜法,可以证明 CuInS2生长在石墨烯纳米网中。与传统的铂对电极电池（6·90％）相比,这种纳米复合材料具有相对较好的光电转化率（6·28％）。     

Tuning Li3PO4 modification on the electrochemical performance of nickel-rich LiNi0.6Co0.2Mn0.2O2

Surface deterioration occurs more easily in nickel-rich cathode materials with the increase of nickel content. To simultaneously pre-vent deterioration of active cathode materials and improve the electrochemical performance of the nickel-rich cathode material, the surface of nickel-rich LiNi0.6Co0.2Mn0.2O2 cathode material is decorated with the stable structure and conductive Li3PO4 by a facile method. The LiNi0.6Co0.2Mn0.2O2–1wt％, 2wt％, 3wt％Li 3PO4 samples deliver a high-capacity retention of more than 85％ after 100 cycles at 1 C under a high voltage of 4.5 V. The effect of different coating amounts (0–5wt％) for the LiNi0.6Co0.2Mn0.2O2 cathode is analyzed in detail. Results show that 2wt％ coating of Li3PO4 gives better performance compared to other coating concentrations. Detailed analysis of the structure of the samples during the charge?discharge process is performed by in-situ X-ray diffraction. It is indicated that the modification for LiNi0.6Co0.2Mn0.2O2 cathode could protect the well-layered structure under high voltages. In consequence, the electrochemical performance of modified samples is greatly improved.