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1.
Hierarchical structured ZnFe2O4@reduced graphite oxide@TiO2 (ZnFe2O4@RGO@TiO2) nanocomposite was prepared by an electrostatic layer-by-layer route, which played a synthetic effect of Fenton oxidation of ZnFe2O4 and photocatalytic oxidation of TiO2 to degrade fulvic acid (FA) solution under visible-light irradiation. In this method, RGO, as the middle layer, can effectively promote the photo-induced electron flow between the ZnFe2O4 and TiO2 and further improve the efficiency of the photo-Fenton oxidation. The influencing factors on photo-Fenton oxidation, including solution pH, catalyst, and H2O2 dosage, have also been investigated. The results illustrated that the ternary composite presented the enhanced catalytic performance. Under visible light irradiation, the degradation efficiency of the sample on the FA solution can reach 95.4% within 3 h. In addition, the catalyst exhibited superior stability and reusability, and its degradation efficiency was still up to 90% after 5 cycles. Therefore, the composite will be a kind of efficient photocatalyst and had a promising application for visible-light driven destruction of organic pollutants. 相似文献
2.
Guofeng Xu Jianling Li Xinping Li Yanying Liu Feixiang Ding Xindong Wang Feiyu Kang 《Ionics》2017,23(9):2285-2291
Lithium-excess oxide shows great potential for its high specific capacity of exceeding 280 mAh g?1. However, the poor rate capability caused by the poor electrochemical kinetics condition as well as the structure instability block the way of its application. Here, we aimed to improve the kinetics circumstance for lithium ion transference through the material bulk by synthesizing lithium-excess oxide with high specific surface area. Petal-like nanoplates and nanoparticles with excellent electrochemical performance were obtained at different sintering temperatures and times by the electrospinning-sintering method, which facilitates the sufficient contact of electrode and electrolyte and helps to reduce the polarization during the electrochemical reaction process. Cyclic voltammetry tests verify that a portion of oxidized oxygen is reduced reversibly at 3.0 V and the reduction of oxygen contributes to the discharge capacity. Electrochemical impedance spectroscopy plots illustrate the ameliorative electrochemical kinetics is conductive to the oxidation of oxygen at 4.5 V. 相似文献
3.
Yang Yang Yun-Hua Li Ya-Fei Zhao Peng-Wei Li Qiao-Xia Li 《Journal of nanoparticle research》2018,20(1):12
A Pd/WO3/C nanocomposite with 3-aminopropyltrimethoxysilane (APTMS)-functionalized tungsten oxide nanosheets (Pd/WO3/C-APTMS) was synthesized and applied as the efficient anode catalyst for direct formic acid fuel cells (DFAFCs). The mechanism for synthesizing the nanocomposite is as follows: initially, [PdCl4]2? was assembled onto the tungsten oxide nanosheets modified with APTMS. Following this, Pd nanoparticles were reduced via traditional impregnation reduction of [PdCl4]2? with NaBH4. The transmission electron microscope (TEM) images revealed that the Pd nanoparticles were uniformly dispersed on WO3 nanosheets and were approximately 2.7 nm in size. The electrochemical test results showed that enhanced electrocatalytic activity for the formic acid oxidation reaction (FAOR) was obtained on the Pd/WO3/C catalyst compared with Pd/C. The higher electrocatalytic activity might be attributed to the uniform distribution of Pd with smaller particles. Furthermore, it is likely that the improvement in catalytic stability for the Pd/WO3/C catalyst is due to the hydrogen spillover effect of WO3 particles. These results indicate that this novel Pd/WO3/C-APTMS nanocomposite exhibits promising potential for use as an anode electrocatalyst in DFAFCs. 相似文献
4.
Weibo Zhu Zhenyuan Zhuang Zhiya Lin Yanmin Yang Yingbin Lin Zhigao Huang 《Ionics》2016,22(9):1533-1540
Layered LiNi1/3Co1/3Mn1/3O2 cathode material is synthesized via a sol-gel method and subsequently surface-modified with Eu2O3 layer by a wet chemical process. The effect of Eu2O3 coating on the electrochemical performances and thermal stability of LiNi1/3Co1/3Mn1/3O2@Eu2O3 cells is investigated systematically by the charge/discharge testing, cyclic voltammograms, AC impedance spectroscopy, and DSC measurements, respectively. In comparison, the Eu2O3-coated sample demonstrates better electrochemical performances and thermal stability than that of the pristine one. After 100 cycles at 1C, the Eu2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode demonstrates stable cyclability with capacity retention of 92.9 %, which is higher than that (75.5 %) of the pristine one in voltage range 3.0–4.6 V. Analysis from the electrochemical measurements reveals that the remarkably improved performances of the surface-modified composites are mainly ascribed to the presence of Eu2O3-coating layer, which could efficiently suppress the undesirable side reaction and increasing impedance, and enhance the structural stability of active material. 相似文献
5.
Influences on oxidation voltage and holding time on poly(3-methylthiophene) film for electrochromic stability 下载免费PDF全文
《中国物理 B》2018,(12)
In this study, we report the influences of oxidation potential and holding time on the electrochromic(EC) stability of poly(3-methylthiophene)(P3MT) film during the electrochemical reaction. The cycle stability and transmittance changes of the film were investigated by optimizing the oxidation potential, and its chemical compositions were measured by x-ray photoelectron spectra after multiple electrochemical cycles. High oxidation potentials can increase the P3MT film color contrast and decrease its cycle stability because of accelerating chemical decomposition. Moreover, the holding time with potential pulsing was analyzed by using the optical memory of P3MT at an optimized oxidation potential, which revealed the reduced voltage duration saved energy consumption by 11.6% and improved the EC cycle stability without changing in color contrast. 相似文献
6.
The platinum-gold bimetallic nanoparticles supported poly(cyclotriphosphazene-co-benzidine)-grafted graphene oxide (poly(CP-co-BZ)-g-GO) composite has been prepared for electrochemical performance studies. Cyclic voltammetry and chronoamperometric studies were carried out to check the electrochemical properties of Pt-Au/poly(CP-co-BZ)-g-GO and Pt/poly(CP-co-BZ)-g-GO catalysts for methanol, ethylene glycol and glycerol in alkaline medium. The morphology and crystalline structure of the prepared Pt-Au/poly(CP-co-BZ)-g-GO and Pt/poly(CP-co-BZ)-g-GO and catalysts have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FT-IR). From the electrochemical results, it was concluded that Pt-Au/poly(CP-co-BZ)-g-GO catalyst shows higher catalytic activity and stability compared to Pt/poly(CP-co-BZ)-g-GO catalyst. The catalytic activity of Pt/poly(CP-co-BZ)-g-GO catalyst has been compared with Pt/poly(CP-co-BZ), Pt/GO and Pt/C catalysts. In addition, oxidation current of ethylene glycol is higher than the methanol and glycerol in alkaline medium on the prepared catalyst. 相似文献
7.
In this study, oxidation of bisphenol-A (IUPAC name – 2,2-(4,4-dihydroxyphenyl, BPA), which is an endocrine disrupting phenolic compound used in the polycarbonate plastic and epoxy resin industry, was investigated using sono-photo-Fenton process under visible light irradiation in the presence of an iron containing perovskite catalyst, LaFeO3. The catalyst prepared by sol–gel method, calcined at 500 °C showed a catalytic activity in BPA oxidation using sono-photo-Fenton process with a degradation degree and a chemical oxygen demand (COD) reduction of 21.8% and 11.2%, respectively. Degradation of BPA was studied by using individual and combined advanced oxidation techniques including sonication, heterogeneous Fenton reaction and photo oxidation over this catalyst to understand the effect of each process on degradation of BPA. It was seen, the role of sonication was very important in hybrid sono-photo-Fenton process due to the pyrolysis and sonoluminescence effects caused by ultrasonic irradiation. The prepared LaFeO3 perovskite catalyst was a good sonocatalyst rather than a photocatalyst. Sonication was not only the effective process to degrade BPA but also it was the cost effective process in terms of energy consumption. The studies show that the energy consumption is lower in the sono-Fenton process than those in the photo-Fenton and sono-photo- Fenton processes. 相似文献
8.
Anke Hagen Marie Lund Traulsen Wolff‐Ragnar Kiebach Bjoern Sejr Johansen 《Journal of synchrotron radiation》2012,19(3):400-407
Solid oxide fuel cells (SOFCs) are able to produce electricity and heat from hydrogen‐ or carbon‐containing fuels with high efficiencies and are considered important cornerstones for future sustainable energy systems. Performance, activation and degradation processes are crucial parameters to control before the technology can achieve breakthrough. They have been widely studied, predominately by electrochemical testing with subsequent micro‐structural analysis. In order to be able to develop better SOFCs, it is important to understand how the measured electrochemical performance depends on materials and structural properties, preferably at the atomic level. A characterization of these properties under operation is desired. As SOFCs operate at temperatures around 1073 K, this is a challenge. A spectroelectrochemical cell was designed that is able to study SOFCs at operating temperatures and in the presence of relevant gases. Simultaneous spectroscopic and electrochemical evaluation by using X‐ray absorption spectroscopy and electrochemical impedance spectroscopy is possible. 相似文献
9.
Yanhui Hou Yechen Wang Huili Yuan Hang Chen Guowei Chen Junhai Shen Liangchao Li 《Journal of nanoparticle research》2016,18(11):343
Heterogeneous photo-Fenton SiO2/Fe3O4/C@TiO2 (SFCT) catalyst with a core-multishell structure and a diameter of about 550 nm was successfully prepared and was characterized by scanning electron microscopy (SEM), TEM, XRD, Raman, and Fourier transform infrared (FT-IR). The results illustrated that anatase TiO2 coexisted with rutile TiO2, in which the anatase phase was the main crystal phase. In addition, the catalytic activity of SFCT catalyst had been evaluated in the catalytic degradation on p-nitrophenol (PNP). The influence factors on the PNP degradation, including SFCT component ratio (m SFC/ m TiO2), H2O2 dosage, solution pH, and PNP concentration, had been investigated. And the contrast experiments about the photo-Fenton catalytic mechanism revealed that the SFCT-2 catalyst possessed a superior activity in the neutral environment due to the optimal activity matching between Fe3O4 and TiO2, and it exhibited the stable catalytic performance after five successive recycles. Therefore, the SFCT-2 catalyst had a promising application for the photo-Fenton degradation of organic contaminant. 相似文献
10.
Apatite-type La9.33Si6O26 thin films were elaborated by co-sputtering of two metallic La and Si targets powered, respectively, by high power impulse
magnetron sputtering and direct current sources, in pure Ar atmosphere, followed by a subsequent high temperature oxidation
treatment in air. The structural and chemical features of these films have been assessed by X-ray diffraction and scanning
electron microscopy (SEM). The film with near lanthanum silicate La/Si atomic ratio deposited on a porous Ni-YSZ cermet substrates
was initially amorphous. After thermal oxidation at 1,173 K in air, the coating crystallised under the expected apatite structure.
SEM observation revealed that both film compactness and thickness increased after thermal oxidation. The conductivity evolution
with temperature of the pure apatite-like lanthanum silicate coatings, as measured by complex impedance spectroscopy, showed
that the activation energy of is quite low compared to the literature data. 相似文献
11.
面对人类对能源的需求持续增长,以及化石能源的日益枯竭和其带来的环境污染问题,太阳能成为主要的可再生清洁能源的来源。讨论了利用太阳能催化生氢或消耗二氧化碳,探索在半导体基光催化剂表面的光催化反应和光化学反应。半导体材料被认为是最有前景的光催化剂,其材料合成是发展先进催化剂的核心。减少电荷重新复合,是提高太阳能转化为化学能的关键,关系到太阳能的转换效率。研究结果发现了提高光催化制氢的关键因素,通过Pt-PdS/CdS催化体系使其量子效率提高到93%,提供了发展高效催化剂体系的方法。 相似文献
12.
Chuangang HuYanxia Cao Lin Yang Zhengyu BaiYuming Guo Kui WangPengle Xu Jianguo zhou 《Applied Surface Science》2011,257(18):7968-7974
To maximize the utilization of catalysts and thereby reduce the high price, a new strategy was developed to prepare highly dispersed Pt-SnOx nanoparticles supported on 8-Hydroxyquinoline (HQ) functionalized multi-walled carbon nanotubes (MWCNTs). HQ functionalized MWCNTs (HQ-MWCNTs) provide an ideal support for improving the utilization of platinum-based catalysts, and the introduction of SnOx to the catalyst prevents the CO poisoning effectively. The as-prepared catalysts are characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. It is found that the HQ functionalization process preserves the integrity and electronic structure of MWCNTs, and the resulting Pt-SnOx particles are well dispersed on the HQ-MWCNTs with an average diameter of ca. 2.2 nm. Based on the electrochemical properties characterized by cyclic voltammetry and chronoamperometry, the Pt-SnOx/HQ-MWCNTs catalyst displays better electrocatalytic activity and stability for the methanol oxidation. It is worth mentioning that the forward peak current density of Pt-SnOx/HQ-MWCNTs catalyst is ca. 1.9 times of that of JM commercial 20% Pt/C catalyst, which makes it the preferable catalyst for direct methanol fuel cells. 相似文献
13.
A. I. Belyaeva A. A. Galuza A. A. Savchenko 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(5):597-600
Field investigations were performed into the nature of oxidation of Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 alloy (Vitreloy-1), a new alloy highly promising for in -vessel mirrors of the ITER (International Thermonuclear Experimental
Reactor). The main methods of investigation were X-ray photoelectron spectroscopy and multi-angle ellipsometry. The resistance
of the optical properties of Vitreloy-1 against radiation impact was explained by the oxidation of the surface layer, based
on the features of the diffusion process in amorphous alloys and of interaction between amorphous metal alloys with hydrogen. 相似文献
14.
L. S. Smirnov I. Natkaniec A. S. Ivanov A. Pawlukojc S. I. Troyanov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(6):982-986
The vibrational modes of hydrogen bonds in CsH5(PO4)2 and NaH5P2O6 compounds are analyzed via inelastic incoherent neutron scattering in a wide range of temperatures and Raman light scattering at room temperature. The energy ranges have been determined for the γ, jg, and ? bands of the vibrational modes of acid hydrogens of these compounds. The dependences of the energy on the length of hydrogen bonds in CsH5(PO4)2 have been revealed. 相似文献
15.
Qingran Zhang Richard F. Webster Soshan Cheong Richard D. Tilley Xunyu Lu Rose Amal 《Particle & Particle Systems Characterization》2019,36(1)
The development of highly active and cost‐effective catalyst materials toward electrochemical water splitting is of great importance for converting and storing the intermittent solar energy in the form of hydrogen. Herein, for the first time, an ultrathin Fe and N‐co‐doped carbon nanosheet encapsulated Fe‐doped CoNi alloy nanoparticle (FeCoNi@FeNC) composite is obtained and applied as a bifunctional catalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). This catalyst exhibits prominent catalytic performances for both HER and OER, which only requires overpotentials of 102 and 330 mV, respectively, to reach a current density of 10 mA cm?2 in alkaline media. The high catalytic activity is intrinsically associated with the presence of Fe in both nanosheets and nanoparticles, which has triggered the occurrence of coordinative effects between Fe‐N‐C and FeCoNi that are beneficial for HER and OER, as revealed by electrochemical techniques. In an overall water splitting electrolyzer, FeCoNi@FeNC is employed as both the cathode and anode catalysts, achieving 12 mA cm?2 at 1.63 V for a duration of more than 12 h. 相似文献
16.
Arvydas Tamulis Mantas Grigalavicius Sarunas Krisciukaitis Giedrius Medzevicius 《Central European Journal of Physics》2011,9(3):775-791
Density functional theory methods were used to investigate various self-assembled photoactive bioorganic systems of interest
for artificial minimal cells. The cell systems studied are based on nucleotides or their compounds and consisted of up to
123 atoms (not including the associated water or methanol solvent shells) and are up to 2.5 nm in diameter. The electron correlation
interactions responsible for the weak hydrogen and Van derWaals chemical bonds increase due to the addition of a polar solvent
(water or methanol). The precursor fatty acid molecules of the system also play a critical role in the quantum mechanical
interaction based self-assembly of the photosynthetic center and the functioning of the photosynthetic processes of the artificial
minimal cells. The distances between the separated sensitizer, fatty acid precursor, and methanol molecules are comparable
to Van derWaals and hydrogen bonding radii. As a result the associated electron correlation interactions compress the overall
system, resulting in an even smaller gap between the highest occupied molecular orbital (HOMO), and lowest unoccupied molecular
orbital (LUMO) electron energy levels and photoexcited electron tunnelling occurs from the sensitizer (either Ru(bpy)32+ or [Ru(bpy)2(4-Bu-4’-Me-2,2’-bpy)]2++ derivatives) to the precursor fatty acid molecules (notation used: Me = methyl; Bu = butyl; bpy = bipyridine). The shift
of the absorption spectrum to the red for the artificial protocell photosynthetic centers might be considered as the measure
of the complexity of these systems. 相似文献
17.
18.
建立在常温、常压条件下准确定量测定溶解乙炔含量的紫外-可见分光光度法,并对乙炔在丙酮、三乙二醇、N,N-二甲基甲酰胺和二甲基亚砜中的溶解特性进行系统考察;采用循环伏安法研究助溶剂丙酮、三乙二醇、N,N-二甲基甲酰胺和二甲基亚砜对乙炔电化学氧化过程的影响以及绿色溶剂TEG对该过程影响的作用机制。实验结果表明在常温、常压条件下,溶解乙炔的含量可采用紫外-可见分光光度法通过紫红色的乙炔铜进行准确测定,N,N-二甲基甲酰胺溶解乙炔的能力最强;在乙炔电化学氧化过程中,水分子和三乙二醇之间强烈的氢键作用是提高乙炔在Na2SO4溶液中溶解度的决定性因素;在含体积分数为9%TEG的0.5 mol·L-1 Na2SO4溶液中,乙炔电化学氧化过程的表观活化能为13.20 kJ·mol-1,属于受吸附控制的不可逆过程。该研究以期寻找一种乙炔的良好溶剂,为乙炔电化学氧化过程的研究、乙炔传感器(尤其是乙炔的电化学传感器)、绿色化学以及乙炔化工等的发展提供理论依据和实验指导。 相似文献
19.
Juntian Fan Tao Dong Daliang Fang Xuefeng Li Xian’en Mo Kaihua Wen Shimou Chen Suojiang Zhang 《Ionics》2018,24(10):2965-2972
In this work, Li2ZrF6, a lithium salt additive, is reported to improve the interface stability of LiNi0.5Mn1.5O4 (LNMO)/electrolyte interface under high voltage (4.9 V vs Li/Li+). Li2ZrF6 is an effective additive to serve as an in situ surface coating material for high-voltage LNMO half cells. A protective SEI layer is formed on the electrode surface due to the involvement of Li2ZrF6 during the formation of SEI layer. Charge/discharge tests show that 0.15 mol L?1 Li2ZrF6 is the optimal concentration for the LiNi0.5Mn1.5O4 electrode and it can improve the cycling performance and rate property of LNMO/Li half cells. The results obtained by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) demonstrate that Li2ZrF6 can facilitate the formation of a thin, uniform, and stable solid electrolyte interface (SEI) layer. This layer inhibits the oxidation decomposition of the electrolyte and suppresses the dissolution of the cathode materials, resulting in improved electrochemical performances. 相似文献
20.
Mengya Feng Guowei Zhang Qinghua Du Li Su Zhipeng Ma Xiujuan Qin Guangjie Shao 《Ionics》2017,23(7):1637-1643
At present, a lot of attention has been paid to the reasonable design and synthesis of materials with core shell structure for high-performance supercapacitors. Herein, the Co3O4@MnO2 core shell arrays on nickel foam are successfully synthesized via a facile and effective hydrothermal method followed with annealing process. The sample was characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Electrochemical performance of the Co3O4@MnO2 material was studied using cyclic voltammetry, charge/discharge cycling, and electrochemical impedance measurements in 6 mol L?1 KOH aqueous electrolyte. The results indicated that the Co3O4@MnO2 material presented excellent electrochemical performance in terms of specific capacitance, cyclic stability, and charge/discharge stability. 相似文献