COMPOSITES PART B-ENGINEERING
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2022
·
IF 11.322
Li Dong,Hongwei Chu,Ying Li,Shengzhi Zhao,Dechun Li
Transition metal oxides (TMOs) are drawing multitudinous interest due to their strong thermochemical stability. In the present work, we proposed a facile strategy to fabricate TiO 2 /CuO nanocomposites . By using the conventional open- and closed-aperture Z-scan technology, the eminent nonlinear optical (NLO) properties of the as-prepared TiO 2 /CuO nanocomposites were demonstrated. In order to deeply investigate the NLO enhancement mechanism, we established a theoretical model to study the photogenerated carriers transfer dynamics at the interface with rate equations and the fouth-order Runge-Kutta algorithm. The simulation results indicated that under pumping irradiation, the carriers transferring from CuO to TiO 2 promoted the nonlinear optical absorption of CuO nanosheets and increased the modulation depth. Experimentally, the transient absorption spectroscopy and broadband time-resolved pump-probe measurements were presented to study the role of the carrier dynamics in the broadband near-infrared region. To further confirm the enhanced NLO response in TiO 2 /CuO nanocomposites, a highly stable dissipative soliton mode-locked Yb-doped fiber laser with TiO 2 /CuO saturable absorber was constructed at 1 μm for the first time. Our work manifested the key effects of the interface in TiO 2 /CuO nanocomposites to boost the NLO features which can be applied in ultrafast photonics applications.
研究领域:
材料科学
·
光学
·
超快光子学
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高影响因子
CHEMICAL ENGINEERING COMMUNICATIONS
·
2023
·
IF 2.5
Junxiao Luo,Weidong Shi,Guofeng Fang,Liang Chen,Liang Zhang
Adding nanoparticles with high thermal conductivity into the work fluid is one of the most significant ways to enhance heat transfer. In this article, the influences of nanoparticle mass concentration (0.5–10.0 wt.%) and temperature (5–25 °C) were investigated on the viscosity of TiO2-propylene glycol nanofluid. At the same time, eight kinds of mass concentrations (0.5–10.0 wt.%) were used to investigate the changing regularity on the surface tension of nanofluid; Accordingly, the modified correlations including nanoparticle concentration were proposed respectively. The experimental results show that the viscosity of the nanofluid increases with the increase in particle concentration. Within the concentration of 10.0 wt.%, the viscosity increases by about 7.0% for every 1.0 wt.%. While the viscosity decreases with the increase in the temperature. The surface tension of the mixture increases slowly with the increase in particle concentration. Within 2.0 wt.%, the surface tension of nanofluid increases by less than 1.0% for every 0.5 wt.%, when the concentration of nanofluid exceeds 2.0 wt.%, surface tension raises less than 1.0% per 2.0 wt.%.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Xiaohui Sun,Xueying Zhao,Xuyang Zhang,Guohua Wu,Xianhui Rong,Xiangwei Wang
Ti3C2Tx MXene is a potential microwave absorption material due to its unique physical and chemical properties. However, the impedance mismatch of MXene results in low microwave absorption. In this work, 2D/2D MXene@TiO2 composites were synthesized via a simple hydrothermal oxidation method, TiO2 is derived in situ from MXene without adding any additional Ti precursors. TiO2 with low permittivity can effectively regulate the impedance matching and enhance loss mechanisms. The MXene@TiO2-6 h composite shows a reflection loss (RL) of −58.3 dB at 11.36 GHz with a thickness of 1.75 mm, and the maximum effective absorption bandwidth (EAB) is 4.08 GHz (13.92–18 GHz) at 1.26 mm. Furthermore, the 2D/2D composite can obtain efficient microwave absorption at different frequencies by adjusting the thickness; RL can reach −39.1 dB at 5.04 GHz with a thickness of 3.5 mm. The radar cross section (RCS) of MXene@TiO2-6 h is lower than −19 dB m2 at −60–60°, and the minimum RCS is −56 dB m2 at 15°. This work provides a valuable experience in developing microwave absorption materials.
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RARE METALS
·
2023
·
IF 8.8
Li Wu-Lin,Zhang Qing-Qing,Dong Lin,Zhang Wen-Jun,Lin Li-Li,Chen Zu-Peng
Photocatalytic reductive amination of biomass-derived aldehydes is a desirable way to selectively upgrade biomass into value-added nitrogen-containing chemicals under mild conditions. However, it is challenging to produce imines in high selectivity because of the undesirable side reactions caused by the activity of functional groups. Here, we demonstrate the highly reactive and selective production of imines from biomass derived aldehydes via the photocatalytic reductive amination, using a defective TiO 2 supported nickel catalyst. The employment of methanol as the hydrogen donor and ammonia solution as the nitrogen source avoids the use of high-pressure H 2 and expensive amines, rendering the current catalytic process safe, economical, and environmentally friendly. In depth investigations attribute the improved separation and transfer of photogenerated charge carriers to the presence of oxygen vacancies and decorated Ni nanoparticles, thereby accelerating the production of imines from benzaldehyde amination (conversion, 95.8%; selectivity, 95.2%). Furthermore, the developed system could be easily translated to the photocatalytic conversions of various biomass derived aldehydes, which provided an example of a cost-effective and sustainable approach for the valorization of biomass derived feedstocks. Graphic abstract
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PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 25
·期 35
·23761-23769
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IF 3.3
Juanqin Xue,Peng Wang,Wen Cheng,Long Shi,Qiang Bi
TiO2/BiOI/CA electrodes with improved conductivity, reduced photoelectron–hole recombination rates, and increased reaction sites based on p–n type heterojunctions were constructed on carbon aerogels (CA) as photoelectrode substrates. Characterization based on ultraviolet-visible diffuse reflectance spectroscopy, photocurrent measurements, and impedance analysis showed that the TiO2/BiOI/CA photoelectrode with a Ti/Bi mole ratio of 0.4 exhibited the best visible light absorption, lowest photogenerated electron–hole pair recombination rate, and strongest photocatalytic degradation, with 90.4% degradation of phenol under 120 min of light. Moreover, the stability of this electrode remained at a high level. This was mainly because the energy levels of TiO2 and BiOI matched each other and the p–n heterojunction formed adjusted the energy band structure of the composite material, widened the electron transfer path, formed an internal electric field between the phase interfaces, had a higher electron transfer rate, and reduced the photogenerated electron–hole recombination rate. Since ˙OH and ˙O2− are the main active substances in the degradation of phenol, the TiO2/BiOI/CA photoelectrodes had higher degradation efficiency than BiOI/CA electrodes. This study provides a unique concept for the treatment of organic pollutant wastewater and electrode design for photoelectrocatalysis.
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PubMed
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
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2023
·Vol. 38
·期 2
·286-291
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IF 1.6
Hu Mei,Xin Jin,Liu Zhenyu,Zeng Hui,Wang Yanze
We studied a method to prepare a novel titanium dioxide (TiO 2 ) composite photocatalyst, starting from improving the separation efficiency of photogenerated electrons and holes. Regular TiO 2 microspheres were prepared by sol-gel method and loaded onto Ti 3 C 2 T x (Mxene). The high electrical conductivity of Mxene was utilized to transfer photogenerated electrons quickly and effectively prevent their recombination. By adjusting the addition amount of Mxene, the hydrogen production efficiency of the sample was greatly improved, and the maximum efficiency reached 135.2 µmol·g −1 ·h −1 , which was twice that of pure TiO 2 . The nanocomposites were characterized by XRD, PL, TEM and SEM analysis and electrochemical methods, and the test proved that the improvement of hydrogen production efficiency was caused by the improvement of the separation efficiency of photogenerated electrons and holes. This work demonstrates the application of Mxene as a catalyst to improve efficiency and broadens the application prospects of Mxene.
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JOURNAL OF MATERIALS SCIENCE
·
2023
·Vol. 58
·期 18
·7571-7582
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IF 4.5
Yang Yang,Lu Jie,Ma Zhichun,Zhao Yi,Wang Shuang,Ge Kai,Yang Yongfang
Two dimensional (2D) CuTCPP/B–TiO 2 composites were successfully synthesized by addition of B–TiO 2 NPs into the system for preparation of 2D CuTCPP nanosheets under hydrothermal condition. 2D CuTCPP nanosheets with large specific surface area can not only act as supportor to decrease the aggregation of B–TiO 2 and improve the adsorption capacity of methylene blue (MB) but also provide more transfer pathway to effectively facilitate interfacial charge transfer and separation of photogenerated electrons and holes, thus leading to a superior efficiency for photodegradation of MB. The photocatalytic degradation rate constant of 2D CuTCPP/B–TiO 2 composites is 0.0486 min −1 , which is about 15.2, 5.92 and 4.23 times that of P25 (k = 0.0032 min −1 ), 2D CuTCPP nanosheets ((k = 0.0082 min −1 ) and B–TiO 2 NPs (k = 0.0115 min −1 ). This study demonstrates that the combination of B–TiO 2 NPs and 2D CuTCPP is a viable strategy to improve the photocatalytic efficiency for degradation of MB.
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APPLIED CLAY SCIENCE
·
2023
·
IF 5.6
Ao Jiang,Yuli Di,Shanhua Chen,Dafu Zhang,Xingyu Chen,Zhengdong Zhang,Xinyi Zhang,Qi Dong
The sol-gel method was used to prepare a series of muscovite/TiO 2 heterostructures for photocathodic protection of 304 stainless steels (304SS). The effects of different mass ratio of muscovite to TiO 2 (1:0.5, 1:1 and 1:1.5, denoted as MT-0.5, MT-1 and MT-1.5, respectively) on the crystal phase, grain size, light absorption properties and photoelectrochemical properties of TiO 2 and muscovite/TiO 2 heterostructures were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–visible diffuse reflection spectroscopy (UV–vis DRS). The corrosion resistances and photoelectrochemical properties of the 304SS coated with muscovite/TiO 2 heterostructures (304SS/MT) were studied through corrosion immersion test and electrochemical workstation in 3.5 wt% NaCl solution, respectively. In addition, Tafel curves and the electrochemical impedance spectroscopy (EIS) measurements were carried out to evaluate the photogenerated electron separation and transfer efficiency, and the interfacial charge transfer resistance of the 304SS and 304SS/MT electrodes, respectively. The time-dependent photocurrent responses of the MT-1 heterostructures demonstrated an enhanced photo-generated cathodic protection performance for 304SS substrates under visible light irradiation compared to TiO 2 . A photoinduced potential drop value for 304SS coated with MT-1 in 3.5 wt% NaCl solution was −0.54 V (vs. SCE). After immersion test, the corrosion image analyses of the 304SS, 304SS-MT, and 304SS coated with physically mixed muscovite/TiO 2 samples showed that the 304SS/MT-1 exhibits the best corrosion resistances . After connecting with 304SS/MT-1 in 3.5 wt% NaCl solution, the corrosion current densities ( i corr ) of 304SS increased significantly under the white light illumination, indicating more photoinduced electrons were migrated from the muscovite/TiO 2 heterostructures to the 304SS compared with that from pure TiO 2 . Furthermore, the simulated charge transfer resistance ( R ct ) of 304SS/MT-1 electrode is smaller than that of the 304SS electrode coated with TiO 2 , indicating that there exists an effective separation of the photogenerated electrons and holes, and a fast interfacial charge transfer after coating muscovite/TiO 2 heterostructures.
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MICROCHIMICA ACTA
·
2023
·Vol. 190
·期 6
·1-9
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IF 5.7
Zeng Yinan,Zhang Min,Peng Kefu,Man Zu,Guo Lu’an,Liu Wenping,Xie Shilei,Liu Peng,Xie Dong,Wang Shoushan,Cheng Faliang
A photoelectrochemical molecular imprinting sensor based on Au/TiO 2 nanocomposite was constructed for the detection of dibutyl phthalate. Firstly, TiO 2 nanorods were grown on fluorine-doped tin oxide substrate by hydrothermal method. Then, gold nanoparticles were electrodeposited on TiO 2 to fabricate Au/TiO 2 . Finally, molecular imprinted polymer was electropolymerized on the Au/TiO 2 surface to construct MIP/Au/TiO 2 PEC sensor for DBP. The conjugation effect of MIP accelerates the electron transfer between TiO 2 and MIP, which can greatly improve the photoelectric conversion efficiency and sensitivity of the sensor. In addition, MIP can also provide sites for highly selective recognition of dibutyl phthalate molecules. Under optimal experimental conditions, the prepared photoelectrochemical sensor was used for the quantitative determination of DBP and the results showed a wide linear range (50 to 500 nM), a low limit of detection (0.698 nM), and good selectivity. The sensor was used in a study of real water samples to show that it has promising applications in environmental analysis. Graphical Abstract
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Lin Dong,Jordi Morales-Vidal,Lili Mu,Licheng Li,Núria López,Javier Pérez-Ramírez,Zupeng Chen
5-Methylfurfural (MF) is a critical commodity chemical used as food additive and synthetic intermediate. Opening a sustainable route towards highly selective synthesis of MF from 5-hydroxymethylfurfural (HMF) is of great significance, but has demonstrated extremely challenging. Herein, we report an efficient process for the selective production of MF from HMF over an anatase-supported gold catalyst (Au/a-TiO 2 ). During the hydrogenolysis of HMF, the desired C O bond is maintained and MF can be obtained in a high yield of 83.1 %, exhibiting excellent stability both in batch and flow operation. A combination of experimental and theoretical analyses attribute the superior performance of Au/a-TiO 2 to the synergistic effect of limited H access, low adsorption of reactants, and avoiding condensation, driven by the high concentration of oxygen vacancies in the support. This study highlights a novel approach of tailoring the coverage of active species for the selective transformation of renewable compounds into high-value-added chemicals.
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CHEMICAL PHYSICS LETTERS
·
2023
·
IF 2.8
Chunzheng Wu,Ling Fang,Fangjie Ding,Genxiang Mao,Xiaogu Huang,Shun Lu
Ultra-small Pt nanoparticles loaded on TiO 2 through in-situ photo-deposition for H 2 production via photo reforming of wastepaper was prepared in this study. The effect of noble metal cocatalyst, Pt loading, content of paper (e.g., napkin), and concentration of NaOH was investigated. Consequently, a highest H 2 production rate of 614.7 µmol/g/h was achieved in the optimum condition. It was found that both the solid paper and the dissolved part in the NaOH solution could scavenge the photo-generated holes and contribute to H 2 production. Our research provides a potential route for the reuse of wastepaper to produce clean fuel.
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Coatings
·
2023
·Vol. 13
·期 7
·1162
·
IF 3.4
Yizhi Du,Lina Hu,Liting Dong,Shuming Du,Dong Xu
This study aims to solve the icing problem of wind turbine blades in low-temperature environments and to improve the power generation efficiency of wind turbines. In this study, modified TiO2particles (500 nm), butyl acetate solvent, polyaspartic acid ester polyurea (PAE polyurea), and Crestron N75 curing agent were mixed and sprayed on the epoxy resin board surface. Static icing test, dynamic icing test, wear resistance test, and icing adhesion strength test studies were carried out to evaluate the anti-icing performance of the coating as well as its mechanical stability. The results showed that the mechanical stability and anti-icing performance of the coating were relatively optimal when the ratio of modified TiO2particles to PAE polyurea was 1.5. Under this ratio, the static contact angle of the coating was 161.4°, and the rolling angle was 4.7°. The main reason for the superhydrophobic performance after 250 wear cycles was that the TiO2particles were encapsulated by PAE polyurea. The static contact angle of the coating was still greater than 150° after eight icing–de-icing cycles. This paper provides a simple method to prepare a robust superhydrophobic coating and promotes the application of superhydrophobic coatings in the field of passive anti-icing of wind turbine blades.
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