JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Lei Wang,Xudong Liu,Mu Zhang,Xiaoguo Bi,Zhixin Ma,Jinsheng Li,Jialin Chen,Xudong Sun
(Nb 0.5 Ga 0.5 ) x Ti 1−x O 2 (x = 0.05%,0.2%,0.5%,1%,5%) single crystals were prepared by Verneuil method. Even if the doping amount is 0.05%, the dielectric permittivity (ε′) is obviously higher than that of pure rutile TiO 2 (260), reaching more than 10 4 . As the doping amount x increase, the ε′ increases, and reaches the maximum value when x = 5%, but the dielectric loss increases correspondingly. The best dielectric performance (ε′=1.0 ×10 5 , tanδ=0.034 under 1 kHz) is obtained when the doping amount is 0.5%. Even at 10 6 Hz, the dielectric loss is only 0.019, much lower than the reported ceramic samples. This may be due to the fact crystalline materials can effectively reduce defects such as grain boundary, second phase, porosity and segregation. The dielectric spectra, impedance analysis, XPS and DC bias results show that the colossal permittivity (CP) properties could be attributed to EPDD polarization. With the increase of doping concentration (>1%), the hopping polarization occurs, resulting in a slight increase in dielectric loss. These results indicate that TiO 2 crystal materials with lower dielectric loss are good candidates for dielectric materials. Taking TiO 2 crystal as the research object, we can have a clearer understanding of the origin of TiO 2 dielectric properties and the influence of doping ion content, which is of great significance to the development of TiO 2 -based dielectric materials.
研究领域:
材料科学
·
介电材料
·
晶体生长
·
固体物理
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2014
·
IF 2.538
Liuyang Yang,Zhichun Si,Duan Weng,Youwei Yao
Porous WO 3 /TiO 2 hollow microspheres were prepared by a spray drying method for photodegradation of methylene blue and phenol . The catalysts were characterized by X-ray diffraction, Field Emission Scanning Electron Microscope , High Resolution Transmission Electron Microscope , N 2 adsorption–desorption measurements, Raman spectrometer, UV–Vis Diffuse Reflectance Spectroscopy and Zeta-Meter measurements. The results showed that the tungsten oxides mainly existed in highly dispersed amorphous form on anatase when the loading amount of tungsten oxide was below 3 mol%. The improved photocatalytic activity under UV light irradiation of the WO 3 /TiO 2 catalyst mainly arises from the enhanced charge separation efficiency rather than the improved light absorbance by highly dispersed amorphous tungsten oxides. Highly dispersed amorphous WO x can form a shallowly trapped site due to its similar band structure with TiO 2 . The strongly electron-withdrawing of tungsten oxide in highly dispersed state facilitates the electron transition between titanium and WO x , and consequently improves the charge separation. The enhanced acidity of catalyst by WO x in reactant environment also improved the charge separation efficiency due to the timely transition of holes and electrons accumulated on TiO 2 and WO x , respectively. However, the improved photocatalytic activity under visible light irradiation of the WO 3 /TiO 2 catalyst mainly arises from light harvest. TiO 2 containing 3 mol% WO 3 displayed the highest photocatalytic activity under UV light irradiation while that containing 4 mol% WO 3 present highest activity under visible light irradiation.
研究领域:
材料科学
·
光催化
·
环境化学
·
纳米材料
·
无机合成
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Qi Yan,Shuyao Li,Xinglin Tao,Tao Wang,Xiyan Xu,Xingling Wang,Hexing Li,Xiangyu Chen,Zhenfeng Bian
With the rapid development of triboelectric nanogenerators (TENGs) for flexible wearable devices and electronic skins, challenges have gradually emerged related to the electrification surface, such as pollutant contamination and sophisticated surface adaptability. Hence, we report a simple spraying method to produce a shape-adaptive photocatalytic (SAP) triboelectric material with both self-cleaning and shape-adaptive functions. By spraying the polyvinyl alcohol solution with TiO2 photocatalysts and pre-drying cyclic, the SAP film can be adapted to a varied and intricate substrate. The highest transferred charge density of the SAP film reaches 197.5 μC/m2, when it contacts with the PTFE film. At the same time, it can degrade 74.4% of simulated pollutants under sunlight illumination, and 97% of the transferred charge density can be maintained after the degradation process, indicating good self-cleaning function and stable electrical output. Moreover, the spraying method of this allows it to have shape-adaptive functions. Accordingly, the SAP film can be deposited on the rectangular pyramid and hemispherical surface for fabricating TENGs with special shapes. This low-cost and simple spraying method further promotes the commercialized application of TENGs in the field of wearable devices and skin sensors.
研究领域:
纳米技术
·
能量收集
·
材料科学
·
可穿戴电子学
·
环境功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2023
·Vol. 37
·期 6
·1105-1113
·
IF 1.6
Tang Hailong,Wang Min,Ju Tangtong,Dai Yue,Wang Meiling,Ma Yongqing,Zheng Ganhong
TiO 2 /graphene composite was synthesized in the vapor environment of isopropanol. In order to improve the properties of composite, N-doped of TiO 2 /graphene with different N/Ti molar ratio was prepared in the vapor environment of deionized water and used urea as the source of nitrogen. The N-doped occupies in the interstitial sites of TiO 2 lattice, substitutes for O element in TiO 2 and for C element in graphene, and simultaneously changes the chemical states of Ti and O elements in TiO 2 . N-doped changes the morphology of TiO 2 from nano-sheets to nanoparticles, accompanying with the decrease in specific surface area of the composites, first increases the particle size of TiO 2 and then decreases, and alters the vibration modes of Ti-O-Ti. The composite with R N/Ti =2 exhibits the enhanced photocatalytic degradation performance to methylene blue, and the degradation rate increases from 7.7×10 −2 min −1 for the undoped composite to 9.6×10 −2 min −1 .
研究领域:
材料科学
·
纳米技术
·
光催化
·
复合材料
·
环境工程
✓ 已验证
DOI
高影响因子
WATER SCIENCE AND TECHNOLOGY
·
2022
·Vol. 86
·期 12
·3133-3152
·
IF 2.43
Liu Gen,Lin Yingzi,Li Siwen,Shi Chunyan,Zhang Daihua
Hierarchical porous TiO 2 photocatalytic nanomaterials were fabricated by impregnation and calcination using a peanut shell biotemplate, and TiO 2 /BiFeO 3 composite nanomaterials with different doping amounts were fabricated using hydrothermal synthesis. The micromorphology, structure, element composition and valence state of the photocatalyst were analyzed using a series of characterization methods, including X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), BET surface area (BET), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance (UV-vis), fluorescence spectroscopy (PL) and other technological means. Finally, the degradation mechanism and efficiency of BiFeO 3 composite photocatalyst on the target pollutant triclosan were analyzed using a xenon lamp to simulate sunlight. The results showed that TiO 2 /BiFeO 3 catalyst fabricated using a peanut shell biotemplate has a specific surface area of 153.64 m 2 /g, a band gap of 1.92 eV, and forms heterostructures. The optimum doping amount of TiO 2 /BiFeO 3 catalyst was 1 mol/mol, and the degradation rate was 81.2%. The main active substances degraded were ·O 2 − and ·OH. The degradation process measured is consistent with the pseudo-first-order kinetic model. TiO 2 loading can increase the specific surface area and empty volume of BiFeO 3 and provide more active sites. Through total organic carbon analysis, the mineralization rate of total organic carbon of TiO 2 /BiFeO 3 photocatalyst is 58.9%. h+ and ·OH are the active substances for degradation of triclosan. Relatively speaking, · OH has more obvious inhibition on triclosan and is the main active oxidizing substance.
研究领域:
环境科学
·
材料科学
·
光催化
·
纳米材料
·
污染物降解
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2023
·Vol. 11
·期 45
·24644-24650
·
IF 11.9
Dongrun Xu,Weiye Qu,Junhong Liu,Junxiao Chen,Xue Fang,Liwei Chen,Zhen Ma,Xi Liu,Xingfu Tang,Yaxin Chen
Selective catalytic reduction (SCR) is the most effective technology to control NO emission using commercial V2O5–WO3/TiO2 catalysts, but the nature of active catalytic sites remains under debate. Here we provide evidence demonstrating that dinuclear vanadium–tungsten sites are the most active catalytic sites of conventional V2O5–WO3/TiO2 catalysts, inconsistent with a prevailing view that dimeric vanadium sites are the active sites. The dinuclear vanadium–tungsten sites have inherently stronger acidity than the dimeric vanadium sites, favoring NH3 adsorption. Meanwhile, the vanadium 3d electrons of the dinuclear vanadium–tungsten sites are richer than those of the dimeric vanadium sites, facilitating O2 activation in SCR. Hence, the dinuclear vanadium–tungsten sites have higher SCR activity than the dimeric vanadium sites under identical reaction conditions. This work settles a long dispute on the identification of active sites of conventional V2O5–WO3/TiO2 SCR catalysts, thus having implications for a unified explanation of disparate SCR reaction mechanisms and rational design of improved SCR catalysts.
研究领域:
催化化学
·
环境化学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 104
·期 12
·6290-6298
·
IF 3.784
Xi-xi Sun,Gang Liu,Ruichen Li,Yan Meng,Jiagang Wu
An investigation into photocatalysts mainly focuses on inorganic powders, and their fixation, recycle, and repair in an open and flowing environment remains a problem. Herein, the photocatalytic property of polyvinylidene fluoride (PVDF) is utilized to solve this problem. It can be facilely recycled and repaired because of the form of membrane, and porous structure ensures its sufficient contact with pollutants. In addition, its photocatalytic activity can be effectively modified by compositing TiO 2 nanopowder, which performs better photocatalytic activity than equivalent content TiO 2 powder, originated from the enhanced separation efficiency of electron and hole resulting from the extra driving force maybe generated by PVDF's ferroelectric spontaneous polarization and heterojunction structure, which reduces the recombination of charge carriers. In addition, the pore structure with large density and small size provides more reaction area for the composite structure, which also benefits for the enhancement of photocatalytic activities. Tight combination between PVDF and TiO 2 guarantees the stable activity of the composites under flowing environment, and so PVDF/TiO 2 composite can sustain its initial photocatalytic activity after at least 10 times cycles. More importantly, when the membrane is damaged, it can be easily repaired by the cost of a small quantity of solvent and can maintain its initial photocatalytic activity. This work would promote the understanding of physical mechanisms of enhanced photocatalytic activities, and recycle and repair properties in PVDF- x TiO 2 composites.
研究领域:
材料科学
·
环境工程
·
光催化
·
聚合物复合材料
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Hailong Li,Jiexia Zhao,Weilin Zhang,Jianping Yang,Jun Wang,Mingguang Zhang,Zequn Yang,Liqing Li,Kaimin Shih
Manganese oxide/titanium dioxide (MnO x /TiO 2 , or MnTi) catalyst prepared by an ultrasound-assisted impregnation method was employed for simultaneous nitrogen oxide (NO) reduction and elemental mercury (Hg 0 ) oxidation under a simulated selective catalytic reduction (SCR) atmosphere. An NO reduction rate of 83% and Hg 0 oxidation rate of 96% were simultaneously achieved at a relatively low temperature of 200 °C. Ammonia (NH 3 ) as a reducing agent in the NO-SCR process was systematically investigated for its effect on Hg 0 oxidation. The results showed that NH 3 inhibited Hg 0 oxidation over the low-temperature MnTi catalysis process. In the presence of NH 3 , competitive adsorption between NH 3 and Hg 0 on the MnTi catalyst was partly responsible for the weakening Hg 0 oxidation. NH 3 consumed surface oxygen (O 2 ) on the MnTi catalyst, which also resulted in lower Hg 0 oxidation rate, especially in the absence of gas phase O 2 in the flue gas . More importantly, oxidized mercury was reduced by NH 3 to form Hg 0 with the aid of NO, i.e., the combined presence of NO and NH 3 induced the reduction of oxidized mercury, and hence partially offset Hg 0 oxidation. The effects of individual SCR gases, such as O 2 , NO, and the combinations, on Hg 0 oxidation were also elaborated.
研究领域:
环境科学
·
催化化学
·
大气污染控制
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2017
·
IF 6.065
Zuliang Wu,Zhoubin Zhu,Xiaodong Hao,Weili Zhou,Jingyi Han,Xiujuan Tang,Shuiliang Yao,Xuming Zhang
Non-thermal plasma technology has great potential in reducing polycyclic aromatic hydrocarbons (PAHs) emission. But in plasma-alone process, various undesired by-products are produced, which causes secondary pollutions. Here, a dielectric barrier discharge (DBD) reactor has been developed for the oxidation of naphthalene over a TiO 2 /diatomite catalyst at low temperature. In comparison to plasma-alone process, the combination of plasma and TiO 2 /diatomite catalyst significantly enhanced naphthalene conversion (up to 40%) and CO x selectivity (up to 92%), and substantially reduced the formation of aerosol (up to 90%) and secondary volatile organic compounds (up to near 100%). The mechanistic study suggested that the presence of the TiO 2 /diatomite catalyst intensified the electron energy in the DBD. Meantime, the energized electrons generated in the discharge activated TiO 2 , while the presence of ozone enhanced the activity of the TiO 2 /diatomite catalyst. This plasma-catalyst interaction led to the synergetic effect resulting from the combination of plasma and TiO 2 /diatomite catalyst, consequently enhanced the oxidation of naphthalene. Importantly, we have demonstrated the effectiveness of plasma to activate the photocatalyst for the deep oxidation of PAH without external heating, which is potentially valuable in the development of cost-effective gas cleaning process for the removal of PAHs in vehicle applications during cold start conditions.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
ORGANIC ELECTRONICS
·
2017
·
IF 3.399
Cuncun Wu,Ziru Huang,Yihao He,Wei Luo,Hungkit Ting,Tieyi Li,Weihai Sun,Qiaohui Zhang,Zhijian Chen,Lixin Xiao
Recently, perovskite solar cells have attracted tremendous research interest due to their amazing light to electric power conversion efficiency (PCE). However, most high performance devices usually use mesoporous TiO 2 as the electron transport layer (ETL), which increases cost for practical application. Here, TiO 2 /SnO x Cl y double layer was employed as the ETL for planar perovskite solar cells . Compared with bare TiO 2 , perovskite solar cell based on TiO 2 /SnO x Cl y shows drastically improved power conversion efficiency and reduced hysteresis. These improvements are attributed to TiO 2 /SnO x Cl y which could enhance electron extraction and reduce surface trap-state.
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
高影响因子
SOLID STATE IONICS
·
2022
·
IF 3.699
Haisheng Yi,Yu Liu,Xia Lu
Interfacial chemistry plays an important role in understanding electrode process kinetics of many chemical reactions, e.g. photocatalyst , electrocatalyst , and electrochemistry . In this context, a systematic investigation is conducted to reveal the mechanism of electrode-electrolyte interface between Li 4 Ti 5 O 12 (LTO) spinel and electrolyte molecule, aiming to tackle the notorious package swelling issue in rechargeable batteries. Using the gas chromatography–mass spectrometry and electron microscopy techniques, the interplays between the LTO and dimethyl carbonate (DMC) are uncovered to be a synergetic chemical catalytic process involving the truncated oxygens of the surface Ti O dangling bonds , which are negatively polarized as the catalytic centers with the strong Lewis basicity . The Lewis basic centers catalyze the nucleophilic substitution of DMC with only trace amounts of water, resulting in the gaseous products, such as CO 2 and methanol. These findings deepen the understandings on the fundamental chemistry and catalysis of solid-liquid interfaces, especially the metal oxide-organic interfaces.
研究领域:
电化学
·
催化化学
✓ 已验证
DOI
高影响因子
Small
·
2020
·Vol. 16
·期 26
·2000030
·
IF 11.459
Yaru Liang,Xiang Xiong,Zhuijun Xu,Qingbing Xia,Liyang Wan,Rutie Liu,Guoxin Chen,Shu-Lei Chou
Lithium-ion batteries (LIBs) have been widely applied and studied as an effective energy supplement for a variety of electronic devices. Titanium dioxide (TiO 2 ), with a high theoretical capacity (335 mAh g −1 ) and low volume expansion ratio upon lithiation, has been considered as one of the most promising anode materials for LIBs. However, the application of TiO 2 is hindered by its low electrical conductivity and slow ionic diffusion rate. Herein, a 2D ultrathin mesoporous TiO 2 /reduced graphene (rGO) heterostructure is fabricated via a layer-by-layer assembly process. The synergistic effect of ultrathin mesoporous TiO 2 and the rGO nanosheets significantly enhances the ionic diffusion and electron conductivity of the composite. The introduced 2D mesoporous heterostructure delivers a significantly improved capacity of 350 mAh g −1 at a current density of 200 mA g −1 and excellent cycling stability, with a capacity of 245 mAh g −1 maintained over 1000 cycles at a high current density of 1 A g −1 . The in situ transmission electron microscopy analysis indicates that the volume of the as-prepared 2D heterostructures changes slightly upon the insertion and extraction of Li + , thus contributing to the enhanced long-cycle performance.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）