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(Zn,M)TiO3(M=Co,Ni,Co0.5Ni0.5)固溶体的溶胶-凝胶法合成 总被引:1,自引:0,他引:1
通过改进的溶胶-凝胶工艺在低温(800 ℃)下合成了基于钛酸锌(ZnTiO3)体系的(Zn1-xCox)TiO3、(Zn1-xNix)TiO3和[Zn1-x(Co0.5Ni0.5)x]TiO3陶瓷固溶体。采用X射线衍射分析(XRD)和差示扫描量热法(DSC)等测量技术对产物进行了物相和热稳定性分析。XRD结果表明,获得单一六方相(Zn1-xCox)TiO3、(Zn1-xNix)TiO3和[Zn1-x(Co0.5Ni0.5)x]TiO3时各自的固溶稳定区间为0.5 ≤ x ≤ 1.0, 0.9 ≤ x ≤ 1.0和0.8 ≤ x ≤ 1.0。与此同时,热分析结果证实,伴随钛酸锌基陶瓷体系掺杂钴量的增加,其六方相的热稳定性提高,且效果比掺杂镍更加显著。 相似文献
3.
通过纳米结构材料的设计和组装来改善锂硫电池的电化学性能。在本工作中,成功合成了六边形Co1-xS纳米片修饰的氮掺杂碳纳米管(Co1-xS-CNT)复合材料,并将其用作锂硫电池(LSBs)的硫正极载体。在Co1-xS-CNT/S中,极性六方Co1-xS纳米片可以化学吸附多硫化锂,同时CNT可以为电极材料提供高导电网络。基于物理限域和化学吸附的协同作用,Co1-xS-CNT/S正极表现出优异的电化学循环性能。在0.5C倍率下循环170次,电极仍可保持405.6 mAh·g-1的放电比容量,同时具有超过99.2%的稳定库仑效率。 相似文献
4.
纳米Mn-Zn铁氧体的制备和研究 总被引:10,自引:0,他引:10
Nanosize manganese zinc ferrites were fabricated by hydrothermal precipitation route using Fe2(SO4)3, ZnSO4·7H2O, MnSO4·H2O as material, then some calcinated at 500 ℃ and studied by XRD, TEM, IR and VSM. The results showed that the products were spinel crystal structure and uniformly sized nanoparticles (15~25 nm) with little aggregation. The analysis of IR showed that the superficial water can be eliminated, but that was embedded in crystal lattice can not be removed by calcinating. The effect Zn content x on the lattice (a) of nanosize Mn1-xZnxFe2O4 was also discussed. The lattice of nanosize Mn1-xZnxFe2O4 decreases with x increasing; and its value deviated the standard lattice (a0) of normal size manganese zinc ferrites. A lot of water was absorbed during the hydrothermal process owing to the large surface of nanosize particles. The change of magnetic properties of MnxZn1-xFe2O4 with x increasing was studied: nanosize MnxZn1-xFe2O4 particles synthesized by us exhibited peculiar magnetic properties curve with Zn content (x) increasing, Superparamagnetic behaviors of the synthesized ZnFe2O4 samples were confirmed by magnetic characterization, which can be explained by the difference between the distribution of the metal ions (Mn2+, Zn2+ and Fe3+) among the tetrahedral (A) and the octahedral (B) sites of nanosize ferrite and that of bulk ferrite. 相似文献
5.
纳米钙钛矿LaxSr1-xFe1-yCoyO3复合氧化物的制备和表征 总被引:1,自引:0,他引:1
用甘氨酸-硝酸盐燃烧合成法,制备LaxSr1-xFe1-yCoyO3复合氧化物的陶瓷粉末,对该钙钛矿型氧化物进行了XRD、IR、紫外漫反射光谱及循环伏安曲线分析。结果表明:该复合氧化物粉体平均晶粒为15.3~29.8 nm,为立方和正交晶系。该氧电极具有双功能催化特性,但不完全可逆。对水溶液染料进行光解实验,利用紫外-可见、人工神经网络光度法研究LaxSr1-xFe1-yCoyO3的催化性能。结果表明:CO2+的加入可使LaxSr1-xFeO3的光催化活性有所提高,B位离子(Fe3+,CO2+)改变与加入,使LaxSr1-xFe1-yCoyO3(x=0.7,0.3;y=0.3,0.9,1)光催化活性高于LaxSr1-xFeO3。同时,对5种染料进行紫外光解,在0.75 h,脱色率大于91%,并为动力学一级反应。 相似文献
6.
采用高温固相法在空气中合成了Ba1.97-yZn1-xMgxSi2O7:0.03Eu,yCe3+系列荧光粉。分别采用X-射线衍射和荧光光谱对所合成荧光粉的物相和发光性质进行了表征。在紫外光330~360 nm激发下,固溶体荧光粉Ba1.97-yZn1-xMgxSi2O7:0.03Eu的发射光谱在350~725 nm范围内呈现多谱峰发射,360和500 nm处有强的宽带发射属于Eu2+离子的4f65d1-4f7跃迁,590~725 nm红光区窄带谱源于Eu3+的5D0-7FJ (J=1,2,3,4)跃迁,这表明,在空气气氛中,部分Eu3+在Ba1.97-yZn1-xMgxSi2O7基质中被还原成了Eu2+;当x=0.1时,荧光粉Ba1.97Zn0.9Mg0.1Si2O7:0.03Eu的绿色发光最强,表明Eu3+被还原成Eu2+离子的程度最大。当共掺入Ce3+离子后,形成Ba1.97-yZn0.9Mg0.1Si2O7:0.03Eu,yCe3+荧光粉体系,其发光随着Ce3+离子浓度的增大由蓝绿区经白光区到达橙红区;发现名义组成为Ba1.96Zn0.9Mg0.1Si2O7:0.01Ce3+,0.03Eu的荧光粉的色坐标为(0.323,0.311),接近理想白光,是一种有潜在应用价值的白光荧光粉。讨论了稀土离子在Ba2Zn0.9Mg0.1Si2O7基质中的能量传递与发光机理。 相似文献
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8.
石墨相氮化碳(g-C3N4)是一类非金属聚合物半导体材料, 具有良好的可见光响应、 优异的化学稳定性和可调节的能带结构, 在光催化分解水制氢、 空气净化、 环境修复等领域有着广阔的应用前景. 目前, g-C3N4光催化分解水的研究主要聚焦析氢半反应, 而牺牲试剂的氧化反应以及光生空穴则未被加以利用. 光催化苯甲醇氧化反应具有较高的选择性, 在光催化制氢的同时还能够获得苯甲醛. 我们结合最新国内外研究成果, 系统地综述了g-C3N4在光催化苯甲醇氧化耦合制氢方面的应用, 从分子改性、 显微结构及缺陷调控、 非金属元素掺杂、 金属负载和复合材料设计等5个方面介绍了g-C3N4光催化苯甲醇氧化提升性能的研究策略. 重点总结了g-C3N4的结构和光生载流子分离效率对催化性能的影响, 并对g-C3N4光催化苯甲醛氧化耦合制氢的后续发展进行了展望. 相似文献
9.
通过简单的钴铁前躯体热分解法制备了系列一维Co1-xFexOy(0≤x≤1)多孔纳米材料,并在1 mol·L-1 KOH溶液中研究了其电解水析氧催化性能。研究发现不同Fe掺杂量对材料的结构与电解水析氧催化性能有较大的影响,其中16%(n/n)Fe掺杂量的Co1-xFexOy具有最优的析氧催化性能。在10 mA·cm-2电流密度下其析氧过电位为345 mV,塔菲尔斜率为54 mV·dec-1,并表现出优异的析氧稳定性能。廉价、高效的Co1-xFexOy多孔纳米棒材料有望成为优良的析氧催化剂用于电解水制氢。 相似文献
10.
采用简单沉积-沉淀法合成了Bi2WO6@Bi2MoO6-xF2x(BWO/BMO6-xF2x)异质结,借助XRD、XPS、TEM、SEM、EDS、UV-Vis-DRS、PC和EIS等测试技术对其组成、形貌、光吸收特性和光电化学性能等进行系统表征,并以模型污染物罗丹明B(RhB)的光催化降解作为探针反应来评价Bi2WO6@Bi2MoO6-xF2x异质结的光催化活性增强机制。形貌分析表明,所得Bi2MoO6微球由大量厚度为20~50 nm的纳米片组成;FE-SEM和HR-TEM分析表明,尺寸约为10 nm的Bi2WO6量子点均匀沉积在Bi2MoO6-xF2x微球表面,形成新颖的Bi2WO6@Bi2MoO6-xF2x异质结;与纯Bi2MoO6或者Bi2WO6相比,1∶1Bi2WO6@Bi2MoO6-xF2x异质结表现出更好的光催化活性和光电流性质,其对RhB光催化降解的表观速率常数分别为纯BMO和BWO的6.4和11.6倍。PC和EIS图谱分析表明,Bi2WO6量子点表面沉积显著提高Bi2MoO6-xF2x光生电子/空穴的分离效率和迁移速率;活性物种捕获实验证明了·O2-和h+是主要的活性物种。根据实验结果,探讨了F-掺杂和Bi2WO6量子点之间的协同效应对Bi2MoO6的光催化活性的影响机制。 相似文献
11.
Shao-Qin Peng Yu-Jing Peng Yue-Xiang Li Gong-Xuan lu Shu-Ben Li 《Research on Chemical Intermediates》2009,35(6-7):739-749
Cd x Zn1?x S solid solution photocatalysts were prepared by a hydrothermal process. The photocatalysts were characterized by X-ray diffraction (XRD), UV–vis diffusive reflectance spectroscopy (DRS), and transmission electron microscope (TEM) measurements. Using glucose as an electron donor, photocatalytic hydrogen generation over Pt/Cd x Zn1?x S was investigated. The results show that glucose not only improves the efficiency of photocatalytic hydrogen generation but prevents photocorrosion of Cd x Zn1?x S. Glucose was degraded effectively with the hydrogen generation. The factors which affect photocatalytic hydrogen generation, such as composition and structure of Cd x Zn1?x S solid solutions, irradiation time, initial concentration of the glucose, and concentration of NaOH were studied. 相似文献
12.
Enhanced Photocatalytic Hydrogen‐Production Performance of Graphene–ZnxCd1−xS Composites by Using an Organic S Source
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Dr. Qin Li Huan Meng Prof. Jiaguo Yu Prof. Wei Xiao Yingqiu Zheng Juan Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):1176-1185
In response to the increasing concerns over energy and environmental sustainability, photocatalytic water‐splitting technology has attracted broad attention for its application in directly converting solar energy to valuable hydrogen (H2) energy. In this study, high‐efficiency visible‐light‐driven photocatalytic H2 production without the assistance of precious‐metal cocatalysts was achieved on graphene–ZnxCd1?xS composites with controlled compositions. The graphene‐ZnxCd1?xS composites were for the first time fabricated by a one‐step hydrothermal method with thiourea as an organic S source. It was found that thiourea facilitates heterogeneous nucleation of ZnxCd1?xS and in situ growth of ZnxCd1?xS nanoparticles on graphene nanosheets. Such a scenario results in abundant and intimate interfacial contact between graphene and ZnxCd1?xS nanoparticles, efficient transfer of the photogenerated charge carriers, and enhanced photocatalytic activity for H2 production. The highest H2‐production rate of 1.06 mmol h?1 g?1 was achieved on a graphene–Zn0.5Cd0.5S composite photocatalyst with a graphene content of 0.5 wt %, and the apparent quantum efficiency was 19.8 % at 420 nm. In comparison, the graphene–ZnxCd1?xS composite photocatalyst prepared by using an inorganic S source such as Na2S exhibited much lower activity for photocatalytic H2 production. In this case, homogeneous nucleation of ZnxCd1?xS becomes predominant and results in insufficient and loose contact with the graphene backbone through weak van der Waals forces and a large particle size. This study highlights the significance of the choice of S source in the design and fabrication of advanced graphene‐based sulfide photocatalytic materials with enhanced activity for photocatalytic H2 production. 相似文献
13.
An Efficient,Visible‐Light‐Driven,Hydrogen Evolution Catalyst NiS/ZnxCd1−xS Nanocrystal Derived from a Metal–Organic Framework
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Dr. Xiuxia Zhao Jianrui Feng Jing Liu Prof. Wei Shi Prof. Guangming Yang Prof. Gui‐Chang Wang Prof. Peng Cheng 《Angewandte Chemie (International ed. in English)》2018,57(31):9790-9794
Photocatalytic water splitting for hydrogen production using sustainable sunlight is a promising alternative to industrial hydrogen production. However, the scarcity of highly active, recyclable, inexpensive photocatalysts impedes the development of photocatalytic hydrogen evolution reaction (HER) schemes. Herein, a metal–organic framework (MOF)‐template strategy was developed to prepare non‐noble metal co‐catalyst/solid solution heterojunction NiS/ZnxCd1?xS with superior photocatalytic HER activity. By adjusting the doping metal concentration in MOFs, the chemical compositions and band gaps of the heterojunctions can be fine‐tuned, and the light absorption capacity and photocatalytic activity were further optimized. NiS/Zn0.5Cd0.5S exhibits an optimal HER rate of 16.78 mmol g?1 h?1 and high stability and recyclability under visible‐light irradiation (λ>420 nm). Detailed characterizations and in‐depth DFT calculations reveal the relationship between the heterojunction and photocatalytic activity and confirm the importance of NiS in accelerating the water dissociation kinetics, which is a crucial factor for photocatalytic HER. 相似文献
14.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(31):9938-9942
Photocatalytic water splitting for hydrogen production using sustainable sunlight is a promising alternative to industrial hydrogen production. However, the scarcity of highly active, recyclable, inexpensive photocatalysts impedes the development of photocatalytic hydrogen evolution reaction (HER) schemes. Herein, a metal–organic framework (MOF)‐template strategy was developed to prepare non‐noble metal co‐catalyst/solid solution heterojunction NiS/ZnxCd1−xS with superior photocatalytic HER activity. By adjusting the doping metal concentration in MOFs, the chemical compositions and band gaps of the heterojunctions can be fine‐tuned, and the light absorption capacity and photocatalytic activity were further optimized. NiS/Zn0.5Cd0.5S exhibits an optimal HER rate of 16.78 mmol g−1 h−1 and high stability and recyclability under visible‐light irradiation (λ>420 nm). Detailed characterizations and in‐depth DFT calculations reveal the relationship between the heterojunction and photocatalytic activity and confirm the importance of NiS in accelerating the water dissociation kinetics, which is a crucial factor for photocatalytic HER. 相似文献
15.
Alexander L. Stroyuk Ivan V. Sobran Anna V. Korzhak Alexandra E. Raevskaya Stepan Ya. Kuchmiy 《Colloid and polymer science》2008,286(5):489-498
Photocatalytic activity of CdS and Cd
x
Zn1−x
S nanoparticles in the polymerization of acrylamide and acrylic acid in aqueous solutions has been found. It has been shown
that the most probable way of the photogeneration of primary radicals is the reduction of an adsorbed monomer by the conduction
band electrons of the semiconductor nanoparticles, a monomer oxidation by the valence band holes and atomic hydrogen addition
to a monomer being complementary photoinitiation routes. A correlation between the composition of CdxZn1-xS nanoparticles and their photocatalytic activity in the acrylamide polymerization has been established. It has been shown
that an increase in the quantum yield of the photopolymerization in a sequence СdS < Cd0.75Zn0.25S < CdS0.5Zn0.5S < Cd0.3Zn0.7S originates from a concurrent increase of the conduction band potential of the semiconductor nanoparticles. A kinetic equation
of the photocatalytic acrylamide polymerization has been derived. Quantum yields of the photoinitiation have been found to
be as small as 10−4 to 10−3. 相似文献
16.
A. L. Stroyuk A. E. Raevskaya A. V. Korzhak I. E. Kotenko E. M. Glebov V. F. Plyusnin S. Ya. Kuchmii 《Theoretical and Experimental Chemistry》2009,45(1):12-22
A relation was established between the composition of Cd
x
Zn1–x
S nanoparticles and their ability to accumulate excess negative charge during irradiation. The rate of expenditure of the
accumulated charge depends on the composition of the nanoparticles and is determined by their electric capacitance. A correlation
was found between the photocatalytic activity of the Cd
x
Zn1–x
S nanoparticles in the release of hydrogen from solutions of Na2SO3, their composition, and their capacity for photoinduced accumulation of excess charge. It was shown that Ni0 nanoparticles photodeposited on the surface of Cd
x
Zn1–x
S are effective cocatalysts for the release of hydrogen. It was found that ZnII additions in photocatalytic systems based on Cd
x
Zn1–x
S/Ni0 nanostructures have a promoting action on the release of hydrogen from water–ethanol mixtures.
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 45, No. 1, pp. 8–16, January-February, 2009. 相似文献
17.
The direct growth of ZnSe–CdSe solid solution onto metallic cathodes by electrodeposition from acidic aqueous sulphate solutions
is described. The plating process is studied by simple voltammetry, while the structure and composition of the electrolytic
deposits are investigated by X-ray diffraction. The experimental d-spacing values of the as-grown mixed lattice are compared to data from reference Zn
x
Cd1-x
Se pellets of standard composition, produced by a sintering method. The findings are supplemented with energy-dispersive X-ray
(EDX) elemental analysis. Thereupon, the variation of the mole fraction x in Zn
x
Cd1-x
Se, and the solid phase constitution of the electrodeposits are determined and correlated to the electrochemical conditions
of growth. The resulting films contain admixtures of CdSe compound and metallic Cd. 相似文献
18.
Template‐Free Preparation of Volvox‐like CdxZn1−xS Nanospheres with Cubic Phase for Efficient Photocatalytic Hydrogen Production
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Hangyue Zhou Prof. Qingyun Liu Prof. Weimin Liu Prof. Jiechao Ge Dr. Minhuan Lan Prof. Chao Wang Prof. Jianxin Geng Prof. Pengfei Wang 《化学:亚洲杂志》2014,9(3):811-818
Volvox‐like CdxZn1?xS solid solutions with a cubic zinc blend structure were synthesized through a template‐free ethylene glycol process. Cd(Ac)2 ? 2 H2O, Zn(Ac)2 ? 2 H2O, and thiourea are used as the starting materials and dissolved in ethylene glycol. These reaction precursors and solvent not only contributed to control over the formation of the volvox‐like spherical geometry, but also exerted vigorous domination for existence of cubic‐phase CdxZn1?xS nanostructures. As‐prepared volvox‐like CdxZn1?xS nanospheres have a diameter of around 100 nm with extensional shells. These samples show excellent photocatalytic H2 evolution activity from water splitting under visible‐light irradiation without any cocatalyst or scaffolding, owing to their tunable band gap, cubic zinc blend structure, and unique hierarchical porous structure with a high surface area (as high as 95.2 m2 g?1). 相似文献
19.
Wenxiang Liu Lele Lu Qiang Li Boyuan Wu Ruizhe Zhang Wei Shi Peng Cheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(53):12206-12211
Photocatalytic hydrogen evolution by water splitting is highly important for the application of hydrogen energy and the replacement of fossil fuel by solar energy, which needs the development of efficient catalysts with long-term catalytic stability under light irradiation in aqueous solution. Herein, Zn0.5Cd0.5S solid solution was synthesized by a metal–organic framework-templated strategy and then loaded with MoS2 by a hydrothermal method to fabricate a MoS2/Zn0.5Cd0.5S heterojunction for photocatalytic hydrogen evolution. The composition of MoS2/Zn0.5Cd0.5S was fine-tuned to obtain the optimized 5 wt % MoS2/Zn0.5Cd0.5S heterojunction, which showed a superior hydrogen evolution rate of 23.80 mmol h−1 g−1 and steady photocatalytic stability over 25 h. The photocatalytic performance is due to the appropriate composition and the formation of an intimate interface between MoS2 and Zn0.5Cd0.5S, which endows the photocatalyst with high light-harvesting ability and effective separation of photogenerated carriers. 相似文献
20.
Z. F. Tomashik I. I. Hnativ V. N. Tomashik I. B. Stratiychuk 《Russian Journal of Inorganic Chemistry》2006,51(8):1320-1323
Equal-etching-rate surfaces for single-crystalline CdTe and Cd1-x Zn x Te solid solution samples in etching mixtures of the H2O2-HBr-ethylene glycol (EG) system are mapped under reproducible hydrodynamic conditions using simplex design. The dissolution rate laws for these materials are studied, and the concentration boundaries of existence for polishing and nonpolishing solutions are determined. The increasing zinc concentration in the Cd1-x ZnxTe solid solution increases the etching rates, while the concentration boundaries of the polishing solutions in the diagram do not change significantly. 相似文献