SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Zhongming Wang,Kun Wang,Xiaoying Peng,Qiang Geng,Xun Chen,Wenxin Dai,Xianzhi Fu,Xuxu Wang
The photoconductivity and the gas sensing property of TiO 2 at room temperature under ultraviolet (UV) irradiation were compared with those under visible light irradiation (≥420 nm), respectively. It was found that UV light could cause the photoconductivity of TiO 2 and its sensing response to both ethylene and oxygen, while the visible light at 420 nm could cause the photoconductivity of TiO 2 and its sensing response to oxygen but not to ethylene. This indicates that the photo-assisted gas sensing performance of TiO 2 was dependent on its light-excited behavior: The intrinsic excitation of TiO 2 induced by UV light could produce both the holes and electrons, which exhibited a respective response to ethylene and oxygen, while the extrinsic excitation of TiO 2 induced by visible light maybe only produced the free electrons but not free holes, resulting in only a response to oxygen. Furthermore, it was found that the visible-light enhanced conductivity maybe depend on the Ti–bonded hydroxyls (Ti–OH) at TiO 2 surface. With the removal of Ti–OH by increasing temperature, the visible light could not produce the photoconductivity of TiO 2 . It was proposed that Ti–OH groups act as the shallow trapped level to cause the extrinsic excitation of TiO 2 .
研究领域:
材料科学
·
半导体物理
·
传感器技术
·
光化学
·
表面科学
·
纳米材料
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 24
·11370-11376
·
IF 9.931
Qinglong Fu,Pan Yang,Jingchuan Wang,Hefang Wang,Lijun Yang,Xiaochong Zhao
Simple, safe and economic methods to prepare Ni nanofibers are required for their practical application. Herein, an in situ vacuum thermal reduction strategy is proposed to synthesize Ni nanofibers on a large scale, which involves electrospinning of a nickel acetate/polyvinylpolypyrrolidone/ethyl cellulose (NiAc/PVP/EC) precursor solution, followed by vacuum thermal treatment. Characterization of the morphology and microstructure reveals that the as-prepared Ni nanofibers are composed of nano-size Ni grains and possess a large surface area. Moreover, it has been demonstrated that the content of EC is closely related to the size of Ni grains and thus the surface area of Ni nanofibers. On account of their high specific surface area, the as-prepared Ni nanofibers exhibit efficient catalytic properties for H2 generation from hydrous hydrazine in an alkaline solution.
研究领域:
材料科学
·
纳米技术
·
催化化学
·
能源材料
·
物理化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Ao Li,Binfang He,Guangchao Jin,Dongmei Liu,Jingbo Chen
Li-rich manganese-based cathode material is expected to be extremely promising for next-generation lithium-ion batteries due to its high specific capacity derived from additional anion redox behavior and low cost of the main element manganese. However, the irreversible release of lattice oxygen results in poor structural stability and inferior electrochemical performances , such as low initial Coulomb efficiency, irreversible capacity decay and serious voltage decay, which limits its commercialization. Herein, a simple strategy to improve the structural stability and electrochemical performances by one-step treatment with triethylamine (TEA) at moderate temperature is reported. TEA was used as a surface treatment reagent to prepare the modified Li-rich manganese-based cathode materials with oxygen vacancies and local structural distortion on the surface. The presence of surface distortion layer and oxygen vacancies inhibits irreversible oxygen release. The result exhibits that initial Coulomb efficiency, rate performance and initial discharge specific capacities are improved. After 100 cycles at a current density of 1 C, the specific capacity of the surface-treated material is 204.3 mAh g -1 (172.6 mAh g -1 for the pristine material), with a capacity retention of 81.26%. Even at a high current density of 10 C, the discharge specific capacity of 139.4 mAh g -1 is still achieved, demonstrating the excellent electrochemical performance. This study provides a simple and effective strategy for constructing special surface structures on Li-rich manganese-based materials to achieve high performance.
研究领域:
材料科学
·
电化学
·
能源存储
·
锂离子电池
·
固态化学
✓ 已验证
DOI
高影响因子
IONICS
·
2019
·Vol. 25
·期 10
·4567-4576
·
IF 2.289
Xu Chun-Sheng,Yu Hai-Tao,Guo Chen-Feng,Xie Ying,Ren Ning,Yi Ting-Feng,Zhang Guo-Xu
To improve the stability and performance of the cathode materials, an ionic conductor layer was coated successfully on the surface of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNC) microspheres. The structural analysis confirmed that LiV 3 O 8 coating did not change the basic structure of LMNC, and all obtained materials are solid solutions with a good-layered structure and a good crystallinity. The microscopy measurement showed that the thickness of the coating layer for the LV-3 sample is about 2.5 nm. This appropriate layer is helpful for improving the surface stability of LMNC and the diffusion of lithium, leading to an obvious enhancement of the electrochemical performance. Our result confirmed that the average discharge specific capacities for LV-3 sample at 0.1 C, 0.2 C, 0.5 C, 1 C, and 3 C are respectively 265.9, 219.1, 188.0, 156.3, and 121.5 mAh g −1 , which are much larger than the values of other samples. After 50 cycles at a 1 C rate, the capacity retentions for different samples are 60.7%, 74.0%, 87.6%, and 70.4%, indicating that LV-3 sample exhibits the best performance. Furthermore, EIS measurements showed that the diffusion coefficient for LV-3 sample is calculated to be 1.26 × 10 −15 cm 2 s −1 , which is also the largest value among all considered samples. Our experiments identified that coating an ionic conductive layer on the cathode material surface will significantly improve their rate capacity and cycling stability.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态离子学
✓ 已验证
DOI
高影响因子
Progress in Natural Science-Materials International
·
2019
·Vol. 29
·期 4
·379-383
·
IF 3.31
Yongsheng Fu,Jun Li,Jianguo Li
The effect of CdS content on the photo-induced improvement of hydrogen evolution reaction activity of the Pt/CdS electrocatalyst was investigated. Although the electrons transferred from CdS to Pt in the Pt/CdS electrocatalyst increased with the CdS content under illumination, the electrochemical active surface area of the Pt/CdS electrocatalyst decreased with the CdS content, resulting that the photo-induced improvement of hydrogen evolution reaction activity of the Pt/CdS electrocatalyst decreased with the CdS content.
研究领域:
材料科学
·
催化化学
·
物理化学
·
纳米材料
·
能源化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Yan Liu,Hanpeng Gao,Shuyi Li,Zhiwu Han,Luquan Ren
Inspired by rose petals, a novel and facile method to prepare smart surface with controllable wettability for transfer and patterned storage of droplets was presented. The smart surface was obtained by alternately depositing PDDA and PSS on a copper substrate with mastoid structure prepared by laser processing. It was found that the wettability of the as-prepared copper surface can switch reversibly between superhydrophobic and superhydrophilic state. In addition, the as-prepared surface had excellent physical and chemical stability. In theory, our droplet storage platform can be processed into any size and shape to achieve different requirements for droplet storage. This study provides a simple route to fabricate bioinspired rewritable platform with reversibly switchable wettability for lossless transfer and patterned storage of droplets. It may be helpful for the development of the devices for droplet transfer and functionalized droplet storage. This method can also be applied to biodetection, microfluidic switching, and chemical microreaction.
研究领域:
表面科学
·
微流控
·
生物医学工程
·
功能材料
·
仿生学
·
分析化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 98
·55256-55262
·
IF 3.708
Zhijian Wu,Ya Xiong,Guoqiang Guan,Lingjun Kong,Shuanghong Tian
A new pyrolytic process was successfully used to prepare hollow-like spherical sludge chars (HSC). In the process, pre-formed cotton spheres with a low density were firstly coated by a layer of sludge paste containing ZnCl2 to form cotton fiber@sludge spheres and then pyrolyzed at 500 °C for 2 h. The resulting HSC possessed a diameter of about 3 mm, a low density of 0.1008 g cm−3 and a high surface area of 1008 m2 g−1. The column adsorption behavior showed that the adsorption capacity and rate constant of HSC for methylene blue reached 186.4 mg g−1 and 0.232 mL min−1 mg−1. The adsorption capacity is about 8.4 and 12 fold of the adsorption capacities of GAC (22.28 mg g−1) and SC (15.26 mg g−1), respectively, and the adsorption rate constant is about 1.3 fold of that of GAC and SC. The great adsorption capacity and rate constant can be considerably dependent on the special hollow-like spherical structure of HSC.
研究领域:
环境科学
·
材料科学
·
化学工程
·
污染控制
·
吸附技术
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 86
·83288-83295
·
IF 3.289
Chongmin Liu,Shuai Liu,Pingxiao Wu,Yaping Dai,Lytuong Tran,Nengwu Zhu,Chuling Guo,Ihsanullah Sohoo
Modified calcium saturated montmorillonite (Mt) was prepared at different 3-aminopropyltriethoxysilane (APTES) loadings through grafting. The as-products were characterized by XRD, FTIR and elemental analysis. Surface analysis such as acidity was examined at different H+ concentrations, showing that the release of OH− from the modified samples increased in the following order: APTES4.0CEC–Mt > APTES3.0CEC–Mt > APTES2.0CEC–Mt > APTES1.0CEC–Mt. Batch experiments were conducted and different conditions (pH, temperature and co-existing ions) were used to evaluate the adsorption capacity of the modified samples. The study developed a new way to confirm the mechanism, which indicated that ligand adsorption was the dominant sorption mechanism for Sr(II) uptake onto APTES–Mts. In general, APTES grafted montmorillonite possessed a higher efficiency of Sr(II) uptake and showed great potential for Sr(II)-rich wastewater treatment.
研究领域:
环境科学
·
材料科学
·
化学工程
·
环境污染治理
·
吸附科学
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2012
·
IF 2.159
Mi Wang,Yanfeng Gao,Lei Dai,Chuanxiang Cao,Xuhong Guo
Nanoscaled SnO 2 with different morphologies has been synthesized via a simple hydrothermal process at 180 °C using polyvinylpyrrolidone (PVP), sodium dodecyl sulfonate (SDS), cetyl trimethyl ammonium bromide (CTAB) or tetrapropyl ammonium bromide (TPAB) as surfactant . All the prepared SnO 2 are of a tetragonal crystal structure. Nanocubes, nanorods , nanosheets , nanobelts and nanoparticles were prepared when changing the type and dosage of organic surfactants. It is shown that anionic surfactant (SDS) and cationic surfactant (CTAB or TPAB) at their suitable addition amounts can largely influence the morphologies of SnO 2 nanocrystals . The effect is significantly dependent on the solvent types: water or ethanol. The non-ionic surfactant (PVP) can also change the morphologies like SDS but the impacts are less obvious. The effect of surfactants on the shape and size of SnO 2 nanoparticles was discussed in detail. The particle growth mechanism is described based on the electrostatic interactions and Van der Waals’ forces.
研究领域:
材料科学
·
纳米技术
·
无机化学
·
物理化学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2016
·
IF 2.76
Caili Dai,Zhe Yang,Huili Yang,Yifei Liu,Jichao Fang,Wenxia Chen,Weitao Li,MingWei Zhao
Micelle-to-vesicle aggregate transition is investigated in this work through the addition of β-cyclodextrin 1 (β-CD) in mixed catanionic surfactant aqueous solutions. The catanionic system is composed of 1-hexadecyl-3-methylimidazolium chloride (C 16 mimCl) and sodium oleate (NaOle) which are cationic surfactant and anionic surfactant, respectively. The mixed surfactant solutions can self −assemble into micelles, which are studied by dynamic light scattering measurements and the calculation of molecular interaction parameter. The inclusion complexation of β-CD to C 16 mimCl-NaOle surfactants is studied by surface tension measurements and the calculation of association constants. The dynamic light scattering (DLS), rheological measurements, freeze-fracture transmission electron microscopy(FF-TEM)were conducted to indicate that micelles can transform into vesicles with the addition of β-CD. Finally, the transformation mechanism is proposed. The main reason for micelle-to-vesicle aggregate transition is the inclusion complexation of β-CD to surfactants and it will alter the composition of mixed C 16 mimCl-NaOle surfactant systems which should be responsible for the phase behavior.
研究领域:
胶体化学
·
纳米材料
·
药物递送
·
自组装体系
·
物理化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2015
·
IF 5.056
He Chen,Liang Kong,Yong Wang
Activation by nitric acid oxidation has been combined with atomic layer deposition (ALD) to modify microporous polypropylene (PP) membranes. Nitric acid oxidation with prewetting of t -butanol generates active groups on the inert surface of PP membranes. Metal oxides including Al 2 O 3 and TiO 2 are subsequently ALD-deposited on the activated membrane. Nitric acid oxidation is a mild approach to activate PP membranes. A short immersion in nitric acid for 10 min is able to generate oxygen/nitrogen-containing active species on the membrane surface , which leads to an evident increase (38%) in the membrane permeability. The mechanical stability and the integrity of the porous structure are well preserved after activation. Surface elemental analyses and microscopy observations confirm the successful deposition of metal oxides thin layers onto the activated membranes. In the deposition of either Al 2 O 3 or TiO 2 , the hydrophilicity of the deposited membranes is continuously improved with increasing ALD cycles, resulting in further increase in water flux. After 100 ALD cycles, the flux is doubled compared to that of the bare membrane. Al 2 O 3 is more efficient in enhancing the hydrophilicity and permeation than TiO 2 under identical deposition conditions because of the faster growth of Al 2 O 3 on the activated PP surface.
研究领域:
材料科学
·
膜技术
·
表面化学
·
高分子化学
·
化学工程
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2021
·
IF 8.071
Yanping Bao,Jinhao Lai,Yishun Wang,Zheng Fang,Yongshi Su,Daniel S. Alessi,Nanthi S. Bolan,Xiaolian Wu,Yan Zhang,Xueding Jiang,Zhihong Tu,Hailong Wang
Iron (III) co-precipitation with dissolved organic matter (DOM) is pervasive in many natural environments. However, the effects of DOM on the formation of Fe(III) hydroxysulfate (FHS) and its environmental implications are poorly understood. In this study, fulvic acid (FA) was used as a model DOM compound, and experiments were devised to investigate the effects of FA on the formation of FHS. In addition, the Pb(II) adsorption capabilities of FHSs biosynthesized under various FA dosages, including kinetics and sorption isotherm experiments, were conducted. These experiments showed that co-precipitation of FA promoted the formation of Fe-FA composites, FA-doped schwertmannite , and small particles of jarosite . Co-precipitates are more enriched in carboxyl (–COOH) functional groups due to their preferential binding with FHS. The adsorption kinetics , isotherms and mechanisms of Pb onto the biosynthesized FHSs were then comprehensively characterized and modeled. Though the specific surface area decreased with increasing FA loading, the introduction of FA into FHSs increased Pb(II) adsorption, with the highest concentration of FA addition improving the removal capacity of Pb(II) to 91.54%. Kinetics studies and intra-particle diffusion models indicated that the adsorption of Pb(II) onto the FHSs was correlated with the number of active sites, and two adsorption steps: surface adsorption and the diffusion of Pb(II) in channels inside the biosynthesized FHSs, are suggested. The adsorption mechanism was attributed to cation exchange between Pb(II) and –OH and –COOH functional groups, and the co-precipitated FA provided additional sites for Pb(II) adsorption by FHS.
研究领域:
环境地球化学
·
水处理技术
·
胶体与界面化学
·
污染控制化学
·
功能材料
·
吸附科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）