Journal of the American Chemical Society
·
2014
·
IF 11.444
Xibin Pang,Wei Chang,Chuncheng Chen,Hongwei Ji,Wanhong Ma,Jincai Zhao
The molecules O2 and H2O dominate the cleavage of aromatic sp2 C–C bonds, a crucial step in the degradation of aromatic pollutants in aqueous TiO2 photocatalysis, but their precise roles in this process have remained elusive. This can be attributed to the complex oxidative species involved and to a lack of available models for reactions with a high yield of direct products. Here, we used oxygen-18 isotope labeled O2 and H2O to observe the aromatic ring-opening reaction of the model compound 3,5-di-tert-butylcatechol (DTBC), which was mediated by TiO2 photocatalysis in an aqueous acetonitrile solution. By analyzing the primary intermediate products (∼75% yield), especially the seven-membered ring anhydrides that were formed, we obtained direct evidence for the oxygen atom of dioxygen insertion into a C–C bond of the aromatic ring. This indicates that molecular oxygen is the ultimate ring-opening agent in TiO2 photocatalysis and that it undergoes single O atom incorporation rather than the previously proposed molecular oxygen 1,2-addition processes. The ratio of intradiol to extradiol products depends on the particle size of TiO2 catalysts used, which suggests that the O2 activation is correlated with the available coordination sites on the TiO2 surface in the photocatalytic cleavage of the aromatic ring.
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DOI
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Jie Yang,Ling Zhou,Xin-Yue Wang,Gao Song,Li-Jun You,Ju-Mei Li
Herein, the robust core-satellite Ag/TiO 2 /Ag composite nanospheres were successfully developed. We firstly fabricated large silver nanoparticles with sufficient plasmonic activity as cores and then encapsulated uniform titanium dioxide interlayer shell around Ag cores, which serves as the highly functionalized substrates to achieve uniform and plentiful surface chemical properties. Next, the outer shell of small silver satellites was formed in-situ via controllable reduction of AgNO 3 by n -butylamine, which acts as the remarkable enhancer for surface enhanced Raman scattering (SERS). The Ag/TiO 2 /Ag composite nanospheres with exceptional SERS sensitivity were easily prepared via facilely tuning the coverage and grain sizes of silver satellites. Then the optimized Ag/TiO 2 /Ag composite nanospheres were employed to quantitatively detect methylene blue (MB) in solution. The results showed good linear relationship between SERS intensities and logarithm concentrations of MB and the limit of detection is low to 10 −10 M. Moreover, the highly uniform and robust Ag/TiO 2 /Ag composite nanospheres display outstanding reproducibility (RSD = 4.02%) and highly storage stability. Owing to the intrinsic catalytic activity of small Ag satellites, Ag/TiO 2 /Ag nanospheres were further applied to effectively follow the degradation reaction process of crystal violet by SERS. Altogether, the core-satellite Ag/TiO 2 /Ag nanospheres present multiple SERS application potential in various fields, such as quantitative chemical analysis, trace detection of pollutants and in-situ reaction monitoring.
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Journal of Materials Chemistry C
·
2020
·Vol. 9
·期 5
·1593-1603
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IF 7.059
Guoming Gao,Ximeng Wang,Qifeng Chen,Caibo Xie,Jie Zheng,Huailin Fan,Lulu Ma,Ruifang Guan,Yanfen Fang,Xun Hu
Surface fluorinated TiO2 has received extensive attention in recent years due to the improved photocatalytic reactivity compared with that of pure TiO2. However, the synergy of surface fluorine (FS) and oxygen vacancy (VO) is not clear and needs further study. Here we systematically studied the effect of FS, VO and acidic sites of TiO2 nanosheets on the selective photocatalytic oxidation of benzylamine to imine. The photocatalytic activity first increased and then decreased as the content of FS decreased and VO increased. The photocatalytic activity reached a summit with the imine yield of 92.1% over TiO2-B-6 h, which is mainly due to the synergy between FS and adjacent VO, forming the frustrated Lewis pair that boosts the activation of O2. The varied contents of FS and VO not only cause an evident change in the amount of acidic sites, but also affect the band structure and separation efficiency of charge carriers. The experimental and calculation results demonstrate that the coexistence of FS and VO boosted the separation efficiency, density and mobility of photogenerated charge carriers, resulting in the improved photocatalytic activity. The improved photocatalytic activity can be attributed to the combined effects of FS, VO and acidic sites. This work provides a strategy for the explicit regulation of surface species on TiO2 nanosheets for improved photocatalytic activity.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 14
·12045-12054
·
IF 2.324
Huang Zhaohui,Chen Hui,Zhao Lei,He Xuan,Fang Wei,Du Yingying,Li Weixin,Wang Guanghui,Zhang Fuqing
With increasing concern about the problems of environmental pollution and energy, the visible light photocatalytic for dye degradation is receiving considerable attention. CdSe quantum dot (CdSe QDs) sensitized MIL-125/TiO 2 @SiO 2 biogenic hierarchical materials (CMTS) has been fabricated through dual modification of CdSe with TiO 2 and MIL-125, that is the metal–organic framework (MOF) with Ti ions as metal centers and terephthalic acid as the organic ligand. The hierarchical porous heterostructured MIL-125/TiO 2 @SiO 2 composites are firstly obtained by a biogenic-templated method using rice husk as biomorphic. CdSe QDs as sensitizer is further deposited on MIL-125/TiO 2 @SiO 2 via a dipping method. This strategy applies CdSe, MIL-125, and TiO 2 undergo a two-level heterostructure, setting a stage for efficient charge separation. In addition, CMTS possesses a hierarchical porous structure in scale from micrometer to nanometer with high BET surface area. As a result, the CMTS can efficiently adsorption target, improving light harvesting and promoting degradation of organic waste from water. Meanwhile, Rhodamine B aqueous solution can be degraded more than 98% by CMTS in 100 min under visible light irradiation.
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SENSORS AND ACTUATORS B-CHEMICAL
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2019
·
IF 6.393
Xiao Wang,Yang Li,Zhiying Li,Shouwei Zhang,Xiaolong Deng,Gang Zhao,Xijin Xu
Considering the poor sensing abilities and high working temperatures for trace triethylamine (TEA) detection, design and fabrication of TEA gas sensors with high sensitivity and low power consumption are still desired. Decorating p-type substrate with n-type semiconductor to form p-n junction is considered to be an effective approach to enhance their sensing abilities. Herein, regular "droplets on salix leaf" like CuO/TiO 2 nanocomposites were designed and successfully synthesized using a two-step method including a water bath treatment and a TiF 4 solution etching process. Surface characterizations indicated that the CuO substrate exhibited a salix leaf like nanosheets structure with massive TiO 2 nanoparticles (about 11 nm) decorated on its surface. Excitingly, gas sensing results showed that the CuO/TiO 2 sensors exhibited a high sensing response of 12.7–5 ppm TEA at a low working temperature (160 °C) and possessed a low detection limit (0.5 ppm). The sensing mechanism was also proposed and attributed to the massive highly dispersed p-n junctions between CuO and TiO 2 nanoparticles, which could significantly change the electrical conductivity and oxygen adsorption abilities. In addition, X-ray photoelectron spectroscopy and Electron paramagnetic resonance measurements confirmed the existence of large amounts of surface oxygen vacancy regions and chemisorbed and dissociated oxygen species, which were beneficial to their gas sensing abilities. This work provides a new strategy to fabricate highly sensitive trace TEA gas sensing materials with low working temperatures, which will also promote the application of p-type gas sensors.
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ENVIRONMENTAL RESEARCH
·
2022
·
IF 8.431
Ying Liang,Guohe Huang,Yongping Li,Yao Yao,Xiaying Xin,Xiang Li,Jianan Yin,Sichen Gao,Yuwei Wu,Xiujuan Chen,Renfei Feng
The challenge from pathogenic infections still threatens the health and life of people in developing areas. An efficient, low-cost, and abundant-resource disinfection method is desired for supplying safe drinking water . This study aims to develop a novel Ti 3+ doping TiO 2 nanoparticle decorated ceramic disk filter (Ti 3+ /TiO 2 @CDF) for point-of-use (POU) disinfection of drinking water. The production of Ti 3+ /TiO 2 @CDF was optimized to maximize disinfection efficiency and flow rate. Under optimal conditions, the log reduction value (LRV) could reach up to 7.18 and the flaw rate was 108 mL/h. The influences of environmental factors were also investigated. Natural or slightly alkaline conditions, low turbidity , and low concentration of humic acid were favorable for the disinfection of Ti 3+ /TiO 2 @CDF, while co-existing HCO 3 − ions and diatomic cations (Ca 2+ and Mg 2+ ) exhibited the opposite effect. Furthermore, the practicability and stability of Ti 3+ /TiO 2 @CDF was demonstrated. Ti 3+ /TiO 2 @CDF showed high disinfection efficiency for E. coli and S. aureus under a range of concentrations. Long-term experiment indicated that Ti 3+ /TiO 2 @CDF was stable. The underlying disinfection mechanisms were investigated and concluded as the combination of retention, adsorption, and photocatalytic disinfection. The developed Ti 3+ /TiO 2 @CDF can provide an effective and reliable disinfection tool for POU water treatment in remote area.
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PubMed
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.
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DOI
PubMed
高影响因子
Environmental Chemistry Letters
·
2022
·Vol. 20
·期 2
·999-1007
·
IF 13.615
Chu Mingna,Li Yang,Cui Kai,Jian Jiahuang,Lu Songtao,Gao Peng,Wu Xiaohong
Carbon dioxide (CO 2 ) emissions and rising fossil fuel consumption have already resulted in global warming and energy crisis. Therefore, conversion of CO 2 into fuels and chemicals is regarded as sustainable solution. Recent research has shown that applying an external electric or optical field promotes CO 2 polarization and, in turn, favors catalytic conversion into organic molecules. Here, a titanium dioxide (TiO 2 ) homojunction was formed on graphitic carbon nitride (g-C 3 N 4 ). Then, massive oxygen defective TiO 2 was obtained by dihydrogen reduction, resulting in a strong built-in electric field, of about 0.19 V, between perfect TiO 2 and defective TiO 2 . The catalyst was analyzed by Kelvin probe force microscopy, time-resolved photoluminescence, wavelength-dependent fluorescence and electron paramagnetic resonance. Results show that the catalyst promotes carbon dioxide polarization and separation of photogenerated charges. The catalyst increased carbon dioxide conversion into carbon monoxide (CO) about sevenfold compared to pristine g-C 3 N 4 , and about sixfold compared to the 20TiO 2 /g-C 3 N 4 precursor, under UV–visible light. This exceptional photocatalytic activity is explained by the formation of a built-in electric field by the defective TiO 2 .
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CHEMICAL ENGINEERING SCIENCE
·
2019
·
IF 3.372
Hamidreza Abadikhah,Ehsan Naderi Kalali,Shabnam Behzadi,Sayed Ali Khan,Xin Xu,Marjan E. Shabestari,Simeon Agathopoulos
In this paper, graphene oxide based nanohybrids decorated with TiO 2 nanoparticles (TiO 2 @rGO) were synthesized and incorporated into the thin film nanocomposite (TFN) membrane for efficient organic solvent nanofiltration (OSN) with antifouling properties. In order to improve the compatibility of TiO 2 @rGO in the polyamide active layer, the nanohybrids were amino-functionalized before their incorporation in the interfacial polymerization process. TiO 2 @rGO incorporated TFN membranes showed intense permeability increment and antifouling characteristics in comparison with the controlled composite membrane and graphene oxide (GO) incorporated TFN membrane. The GO nanosheets structure favors solvent channeling and TiO 2 provides super hydrophilic characteristics, both resulted in a super permeable-hydrophilic OSN membrane with high structural stability and premium antifouling properties.
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RSC Advances
·
2019
·Vol. 9
·期 31
·17941-17949
·
IF 3.049
Xinxin Li,Hebang Shi,Bo Wang,Na Li,Liqiang Zhang,Pengpeng Lv
Surface coating of metal oxides is an effective approach for enhancing the capacity retention of a nickel-rich layered cathode. Current conventional coating techniques including wet chemistry methods and atomic layer deposition are restricted by the difficulty in perfectly balancing the coating quality and scale-up production. Herein, a highly efficient TiO2 coating route through fluidized bed chemical vapor deposition (FBCVD) was proposed to enable scalable and high yield synthesis of a TiO2 coated nickel-rich cathode. The technological parameters including coating time and TiCl4 supply rate were systematically studied, and thus a utility TiO2 deposition rate model was deduced, promoting the controllable TiO2 coating. The FBCVD TiO2 deposition mechanism was fundamentally analyzed based on the TiCl4 hydrolysis principle. The amorphous and uniform TiO2 coating layer is compactly attached on the particle surface, forming a classical core–shell structure. Electrochemical evaluations reveal that the TiO2 coating by FBCVD route indeed improves the capacity retention from 89.08% to 95.89% after 50 cycles.
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高影响因子
Journal of Nanomaterials
·
2020
·
IF 1.98
Yan Zhang,Jiarong Li,Hongyuan Liu
The batch experiments of photocatalytic oxidation-reduction of bromate and ibuprofen (IBP) by graphene oxide (GO) and TiO2 heterostructure doped with F (FGT) particles were conducted. The performance and mechanism of synergistic removal of bromate and IBP by FGT were discussed. The results show that a demonstrable synergistic effect and excellent removal rate of bromate and IBP by FGT were exhibited. When pH is 5.2 and the dosage of FGT is 0.1 g/L, the reaction rate constants of bromate and IBP increased from 0.0584 min-1 and 0.4188 min-1 to 0.1353 min-1 and 0.4504 min-1, respectively, compared with the degradation of bromate or IBP alone. The reaction of photocatalytic synergistic degradation is appropriately fitted through Langmuir-Hinshelwood first-order kinetics. The mechanism of synergistic removal of bromate and IBP by FGT was discussed. And electrons (e-), hydroxyl radical (⋅OH), and superoxide radical (⋅O2-) are the main active species. The electrons play a main role in the bromate reduction, and bromine is the only reduction product, while the oxidation of IBP is the result of ⋅OH and ⋅O2-, and ⋅OH plays a key role. The recombination of electrons and holes is inhibited by simultaneous consumption of bromate and IBP, which makes full use of the redox properties of FGT and plays a synergistic role in the removal of pollutants. The results indicate that photocatalytic oxidation-reduction by FGT is a promising, efficient, and environmental-friendly method for synchronous removal of combined pollution in water.
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ACS Applied Polymer Materials
·
2025
·
IF 4.7
Yuechang Lian,Xiaojing Wang,Shuaiyu Chen,Siyuan Xiang,Yuchao Wang,Shengyang Tao,Wendong Liu
Superhydrophobic fabrics exhibit exceptional potential for oil–water separation, providing effective solutions to environmental challenges such as industrial wastewater and marine oil spills. To streamline the fabrication process and mitigate oily contamination, we developed an in situ growth approach to coat polyester fabric with superhydrophobic TiO2-doped silicone nanofilaments. The coated fabric facilitates highly efficient oil–water separation and exhibits light-driven self-cleaning properties. By precisely controlling the synergistic hydrolysis conditions of methyl trichlorosilane (MTCS) and tetrabutyl titanate (TBT), TiO2-doped silicone nanofilaments were successfully grown on the fabric surface, resulting in a highly porous coating. Integrating this porous structure with the residual methyl groups from MTCS made the fabric superhydrophobic, allowing it to separate various oil–water mixtures efficiently with excellent reusability and high-pressure resistance (2950 Pa). Incorporating TiO2 further endowed the superhydrophobic fabric with light-driven self-cleaning capabilities, enabling the degradation of organic contaminants without compromising its liquid repellency. This simple, cost-effective, and productive fabrication method is highly adaptable, making it valuable for researchers aiming to introduce superhydrophobicity to diverse substrates and surfaces. With its high oil–water separation efficiency and light-driven self-cleaning properties, the superhydrophobic TiO2-doped silicone nanofilament-coated fabric holds significant potential for applications in oil pollution remediation, self-cleaning surfaces, and desalination.
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