APPLIED SURFACE SCIENCE
·
2016
·
IF 3.15
Xin Wang,Zhe Zhao,Dingrong Ou,Baofeng Tu,Daan Cui,Xuming Wei,Mojie Cheng
Ag/TiO 2 nanocomposites comprising of Ag clusters on TiO 2 nanocrystal surfaces are of great significance in catalysts and advanced functional materials. Herein a novel method to synthesize Ag/TiO 2 nanocomposites with Ag clusters under 2 nm on TiO 2 nanocrystal surfaces have been developed. The success of this method relies on a silver mirror reaction in toluene, which refers to the reduction of silver-dodecylamine complexes by acetaldehyde in the presence of mono-dispersed TiO 2 nanocrystals. The prepared Ag/TiO 2 nanocomposites have been characterized by FT-IR spectra, UV–vis absorption spectra, X-ray diffraction (XRD) analysis, ultra high resolution scanning electron microscope (Ultra-HRSEM), high resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectra (XPS). Catalytic activity of Ag/TiO 2 nanocomposites is evaluated for the reduction of p -nitrophenol (4-NP) into p -aminophenol (4-AP) by NaBH 4 . Results demonstrate that Ag/TiO 2 nanocomposites have shown an outstanding catalytic activity as well as a good stability in successive reduction of 4-NP. Noticeably, TOF of Ag/TiO 2 -0.75 nanocomposites obtained in this work is the highest among Ag based catalysts previously reported.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2023
·
IF 8.4
Changlin Xiao,Zihuan Tang,Zhuangzhuang Ma,Xiaotong Gao,Hongqiang Wang,Lichao Jia
Metal oxides based semiconductors promise high performance gas sensing owing to their robustness and low cost, but are limited by their unsatisfied adsorption ability and intrinsic low carriers' mobility. We herein demonstrate an efficient strategy of reducing the adsorption energy and improving the carrier mobility via bulk implanted TiO 2 nanocrystals (NCs) in LaFeO 3 porous structure . By implanting laser generated sub-3 nm TiO 2 NCs in LaFeO 3 samples, the response value (221.8 for 100 ppm formaldehyde) increases about 4 times comparing with that of pristine. Additionally, the sample exhibits high sensitivity and fast response/recovery speed toward formaldehyde steam. The detailed analyses and theoretical calculation proves that the TiO 2 NCs could cause the increase of adsorbed oxygen levels as well as the carrier mobility through forming the heterojunction with LaFeO 3 . This work verifies that TiO 2 NCs implanted LaFeO 3 is a promising formaldehyde sensing material, which provides a new approach to improve sensing ability of metal oxide semiconductor (MOS) based gas sensors.
研究领域:
材料科学
·
传感器技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2024
·
IF 11.2
Wenhao Yang,Dan You,Bingnan Deng,Zhicong Ni,Chunman Yang,Fei Wang,Yingjie Zhang,Xue Li,Yiyong Zhan,Yunxiao Wang
Lithium–sulfur (Li–S) batteries represent a promising energy storage system with the potential to replace traditional lithium-ion batteries. Recent research has explored the practical applications of Li–S batteries. However, due to the insulation properties of the sulfur components and the shuttle effect of polysulfides, the practical application of Li–S batteries is hindered by poor cycle stability and short life. In this study, we developed a controllable three-dimensional Ti 3 C 2 structure design process, and through in situ growth of TiO 2 nanocrystals, we prepared three-dimensional porous materials with TiO 2 @Ti 3 C 2 heterostructures. These materials constructed using two-dimensional lamellar Ti 3 C 2 function as a conductive skeleton to improve the conductivity of the sulfur cathodes, and through the in-situ growth of nano-TiO 2 to introduce more binding sites and provide more chemisorption sites to limit the dissolution and shuttle of polysulfides. In addition, the TiO 2 @Ti 3 C 2 heterointerface generated in situ on the surface of the lamellar structure can induce an internal electric field and increase active reaction sites, which promotes reaction kinetics, accelerates charge diffusion/transport, and promotes LiPS transformation. The materials designed in this study can effectively restrain the shuttle effect by realising the association process of adsorption, capture, and transformation of polysulfides. Thus, when applied as the sulfur cathode frame, it shows a high specific capacity of 1261.41 mAh g −1 at a rate of 0.1 C. In addition, a specific capacity of 66.5% is maintained over 500 cycles at a rate of 1 C. This strategy supports the development of Li–S batteries with extraordinary performance and opens up a promising way to design next-generation electrochemical energy storage devices.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Li Zhang,Xueming Dang,Huimin Zhao
Chemical oxygen demand (COD) is a critical criterion for the analytical assessment of the degree of organic contaminants in an aqueous system. Typically, toxic and expensive reagents are employed in standardized COD analysis methods, leading to secondary pollution. In this work, we developed a rapid electrochemical method for COD detection based on the oxidation of hydroxyl radicals for organics in water by using oxygen vacancy doped anatase/rutile-TiO2 nanoparticles as electrooxidation catalysts. Homojunction interface generated increasing oxygen vacancies for enhancing electron-transfer rate and accelerating H2O oxidation to substantially improve ·OH yield. Oxygen vacancy further increased the oxygen evolution potential of the material. Initially, glucose was chosen as a standard analyte to evaluate electrochemical responses, and water from urban wastewater treatment plants was assessed as real samples subsequently. Excellent analytical characteristics were achieved with the A/R-TiO2 sensor under the optimal conditions, exhibiting a linear range from 1 to 300 mg L–1 and detection limit of 0.1 mg L–1 COD. The estimated COD values obtained from the samples were highly consistent with those determined using the conventional standard dichromate method. We have presented a fast, cost-effective, and ecologically sustainable method that outperforms the standard COD analysis method and holds great potential for the accurate determination of COD and boasts high detection sensitivity and a broad linear range.
研究领域:
环境科学
·
材料科学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 82
·66934-66939
·
IF 3.84
Yong Zhang,Fa-Min Liu
Bone-cuboid, spindle and rhombic TiO2 nanocrystals have been achieved by a simple solvothermal method with the oleic acid and oleylamine volume ratio at 5/5, 4/6 and 3/7, respectively. X-ray diffraction (XRD) and selected area electron diffraction (SAED) results show that all of the three shapes of TiO2 nanocrystals are highly crystallized anatase. Furthermore, for the first time, horizontal and vertical two-dimensional superlattices have been self-assembled with all three shapes of TiO2 nanocrystals by controlling the amount of TiO2 nanocrystals solution and oleic acid. The self-assembly process is primarily driven by maximization of the packing density and tuning entropic depletion attraction forces. In addition, the nanodots, nanorods and nanospheres of TiO2 nanocrystals have been obtained with various amounts of H2O2 (0 ml, 0.05 ml, and 0.25 ml). These ordered two-dimensional superlattices may be suitable for the fabrication of functional ultrathin films which take full advantage of the directional and shape-dependent properties for wide ranging devices.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 15
·6878-6884
·
IF 3.925
Yunfei Ma,Wenhui Yue,Ziwei Ye,Jinglong Zhang
Doping of TiO2 with metals and/or non-metals is an effective strategy for increasing its inherently low photocatalytic activity. In this work, TiO2 nanocrystals co-doped with nitrogen (N) and terbium (Tb) were prepared using a controlled hydrolysis method with water generated in situ via esterification of acetic acid and n-butanol. Compared with undoped TiO2 nanocrystals, co-doped TiO2 nanocrystals exhibited enhanced visible-light absorption and improved charge-carrier separation efficiency due to the synergy between N and Tb. In addition, they also had larger surface area and stronger interaction with the azo-dye acid orange 7 (AO7) compared with undoped TiO2 nanocrystals, giving rise to catalytic activity which was ca. 2× better than undoped TiO2 nanocrystals for photocatalytic degradation of AO7 under visible-light irradiation. For the given N loading, the optimal Tb doping for co-doped TiO2 nanocrystals to achieve the maximum activity was 1%, at which complete decolorization of AO7 was achieved after 5 hours of visible-light irradiation.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2019
·
IF 2.584
Xiaogang Liu,Guiru Du,Meng Li
Combining the advantages of reactive crystal facets and engineering defects is an encouraging way to address the inherent disadvantages of titanium dioxide (TiO2) nanocrystals. However, revealing the true photoreactivity origin for defective TiO2 with coexposed or predominant exposed anisotropic facets is still highly challenging. Here, the photoreactivity of TiO2 nanocrystals with respectively predominant exposed {001}, {101}, and {100} facets before and after Ti3+ doping under both ultraviolet and visible light was compared systematically. In detail, the photocatalytic H2 production for R-TiO2-001, R-TiO2-101, and R-TiO2-100 increased by a factor of 1.34, 2.65, and 3.39 under UV light and a factor of 8.90, 13.47, and 8.72 under visible light. By contrast, the photocatalytic degradation of methyl orange for R-TiO2-001, R-TiO2-101, and R-TiO2-100 increased by a factor of 3.18, 1.42, and 2.17 under UV light and a factor of 4.03, 2.85, and 1.58 under visible light, respectively. The true photocatalytic activity origin for the obtained photoreduction and photo-oxidation ability is attributed to the exposure of more active sites (under-coordinated 5-fold Ti atoms), the facilitated charge transfer among {001}, {101}, and {100} facets, and the Ti3+ energy state with variable doping levels to extend the visible light response. This work hopefully provides significant insights into the photoreactivity origin of defective TiO2 nanocrystals with anisotropic exposed facets.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 17
·12225-12234
·
IF 3.9
Zhixuan Wu,Zhengai Chen,Zhixiang Deng,Ning Dai,Yan Sun,Meiying Ge
In this work, a high-performance room-temperature ammonia (NH3) gas sensor based on Pt-modified WO3–TiO2 nanocrystals was synthesized via a two-step hydrothermal method. The structural properties were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The 10 at% Pt@WO3–TiO2 nanocrystals present the highest NH3 sensing performance at room temperature. Compared with the nanocrystals without Pt modification, the sensitivity of the Pt@WO3–TiO2 sensor is tenfold higher, with the lowest concentration threshold reaching the 75 ppb level. The response is approximately 92.28 to 50 ppm, and response and recovery times are 23 s and 8 s, respectively. The improved sensing was attributed to a synergetic mechanism involving the space charge layer effect and Pt metal sensitization, enhancing the electron transfer efficiency, oxygen vacancy and specific surface area. This study is expected to guide the development of high-performance room-temperature ammonia sensors for clinical breath testing.
研究领域:
材料科学
·
传感器技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ORGANIC ELECTRONICS
·
2018
·
IF 3.68
Yue Wang,Lijie Zhu,Tiening Wang,Yufeng Hu,Zhenbo Deng,Qiuhong Cui,Zhidong Lou,Yanbing Hou,Feng Teng
In this work, we synthesized ligand-free anatase TiO 2 nanocrystals with clean surface and excellent electron extraction. By introducing the trap states between the TiO 2 nanocrystals and the photoactive layer of poly (3-hexylthiophene) (P3HT): (phenyl-C61-butyric-acid-methyl-ester) (PC 61 BM) bulk heterojunction (BHJ), a high performance solution-processed broadband OPD in the visible wavelength is realized and characterized. The OPD shows near spectrally flat response from 350 to 650 nm with high EQE (113%), high responsivity (0.5 A/W) and high detectivity (1.9 × 10 12 Jones) at −1 V. The device also exhibits a high −3 dB bandwidth of 902 kHz and a respectable response speed with a rise time and fall time of 34 μs and 26 μs, respectively. The photocurrent retention measurement at a bias voltage of −1 V implies that the device photoresponse is significantly stable. These OPD performance parameters are sufficient for use in the machine vision or imaging systems. With the help of the J-V curves and light assisted C-V measurements, the underlying working mechanism is proposed as well.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 78
·74376-74383
·
IF 3.289
Maoqin Qiu,Yuan Tian,Zhangxian Chen,Zeheng Yang,Wenming Li,Kai Wang,Lei Wang,Kun Wang,Weixin Zhang
Self-doping by Ti3+ and introducing oxygen vacancies in TiO2 is an important and effective strategy to extend its optical absorption from the UV into the visible region. In this paper, we report the synthesis of a series of Ti3+ self-doped TiO2 nanocrystals via a hydrothermal method using TiCl3 and (NH4)2TiF6 as the source of Ti3+ and Ti4+, respectively. The oxidation of Ti3+ can be inhibited by (NH4)2TiF6 based on Le Chatelier's principle. The samples are characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance, field-emission scanning electron microscopy and transmission electron microcopy, respectively. The results indicate that Ti3+ is localized in the bulk of the as-prepared TiO2 nanocrystals, rather than on the surface. In comparison with pristine TiO2, the Ti3+ self-doped TiO2 nanocrystals exhibit an enhanced photocatalytic activity of 86.3% towards the photodegradation of methylene blue solution under simulated solar light irradiation and 99% under natural solar irradiation. It is found that the molar ratio of Ti4+/Ti3+ used during the synthesis has significant effects on the photocatalytic activity of Ti3+ self-doped TiO2 photocatalysts, since the electronic structures of the resulting Ti3+ self-doped TiO2 nanocrystals can be finely tuned by changing the ratios. The significantly enhanced photocatalytic activity should be due to the self-doping of Ti3+ in TiO2 nanocrystals, which not only increases the optical absorption in the visible light region, but also helps to spatially separate the photogenerated charge carriers.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Qihui Huang,Hui Zheng,Xia Wang,Qi Fu,Tao Gong,Chang Liu,Huijuan Ma,Linmin Ye,Xinping Duan,Youzhu Yuan
Hexamethylene diamine, an important chemical intermediate for polyamides, can be synthesized through the two-step route of caprolactam (CPL) ammonolysis to 6-aminocapronitrile (ACN), followed by hydrogenation. This method has received increasing attention from academia and industry. However, studies on the catalyst structure–performance correlation in CPL ammonolysis are still sporadic. In this work, a series of anatase TiO2 with different oxygen vacancy concentrations was prepared by chemical reduction using NaBH4. The oxygen vacancy on TiO2 surface, presented as Ti3+ sites, substantially enhances the adsorption and activation of NH3, which are demonstrated as the key steps in ammonolysis. Owing to the synergistic effect of Ti3+ and Ti4+ species, the CPL conversion rate and ACN selectivity of 85 and 97%, respectively, are achieved within 250 h. Density functional theory calculations showed that the intermediates on oxygen vacancy-rich TiO2 had a more favorable adsorption energy compared to those on intact TiO2, which is in good agreement with the experimental results.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Energy Technology
·
2019
·Vol. 7
·期 9
·1900247
·
IF 3.163
Pengyuan Gao,Yun Lu,Shuyi Deng,Xun Cui,Qing Zhang,Yingkui Yang
Homogeneous confinement of metal oxide nanoparticles into the heteroatom-doped carbon matrix is highly desirable but remains challenging to develop high-performance anode materials. Herein, a facile simultaneous polymerization of 2-thiophenemethanol (ThM) and titanium ethoxide (TTEO) is proposed to incorporate ultrafine anatase TiO 2 nanocrystals into the continuous S-doped carbon framework by carbonizing the as-produced TiO 2 /poly(2-thiophenemethanol) composites. This in situ crafting process spatially suppresses the growth of TiO 2 by the polymerization of ThM, thus producing size-adjustable TiO 2 nanocrystals (5–50 nm) by tailoring the ratio of TTEO to ThM. It is found that smaller TiO 2 nanocrystals are generated using the lower TTEO-to-ThM ratio. When used as lithium-ion batteries (LIBs) anode, TiO 2 /S-doped carbon (TSC) shows larger reversible capacity, superior rate capability, and better cycling stability compared to pure TiO 2 . A typical TSC with the smallest TiO 2 nanocrystals (8 nm) shows the reversible capacity as high as 386 mAh g −1 at 50 mA g −1 , and retains 55% of initial capacity at 500 mA g −1 , and 96.8% capacity after 500 cycles at 1000 mA g −1 . The excellent electrochemical performance is attributed to the shortened ion diffusion path of ultrafine TiO 2 and the improved electronic conductivity, structural stability, and surface/interface nature by the S-doped carbon matrix.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）