MOLECULES
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2017
·Vol. 22
·期 11
·1943
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IF 2.861
Xiaojia Li,Mingming Zou,Yang Wang
Highly crystalline mesoporous anatase TiO2nanospheres with high surface area (higher than P25 and anatase TiO2) are prepared by a soft-template method. Despite the high specific surface area, these samples have three times lower equilibrium adsorption (<2%) than Degussa P25. The rate constant of the mesoporous anatase TiO2(0.024 min−1) reported here is 364% higher than that of P25 (0.0066 min−1), for the same catalytic loading. The results of oxidation-extraction photometry using several reactive oxygen species (ROS) scavengers indicated that mesoporous anatase TiO2generates more ROS than P25 under UV-light irradiation. This significant improvement in the photocatalytic performance of mesoporous spherical TiO2arises from the following synergistic effects in the reported sample: (i) high surface area; (ii) improved crystallinity; (iii) narrow pore wall thicknesses (ensuring the rapid migration of photogenerated carriers to the surface of the material); and (iv) greater ROS generation under UV-light.Keywords:mesoporous anatase TiO2;high surface area;photocatalytic
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2022
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IF 6.371
Kangning Liu,Jiliang Ma,Xiaopan Yang,Dongnv Jin,Yancong Li,Gaojie Jiao,Shuangquan Yao,Shaolong Sun,Runcang Sun
Photocatalytic biorefinery catches an ocean of attention because of its environmental friendliness. It is widely known that photocatalytic performance of TiO 2 is poor due to the wide bandgap and sluggish electron kinetics. Herein, biochar nanosheet and anatase TiO 2 (denoted as a- TiO 2 @MC) were combined to accelerate the charge separation/transfer and narrow the bandgap of TiO 2 , which is proved by UPS and Mott-Schottky plot analysis. With improved electron kinetics, comes excellent photocatalytic performance, which gave great yield of xylonic acid (52.26%) and lactic acid (49.22%). Furthermore, h + ,·OH, and 1 O 2 exerted positive effects on the synthesis of biomass-derived organic acids, in which the h + plays the major role in the biorefinery over a- TiO 2 @MC, whereas the·O 2 - is not. 1000-fold scale-up experiment indicated that 69.1% of the photocatalytic performance was achieved when compared with the similar conditions irradiated by visible light. This work provides an efficient photocatalytic biorefinery via a facile and low-cost way.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
ChemCatChem
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2018
·Vol. 11
·期 3
·1057-1063
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IF 4.674
Gan Wang,Lijuan Zhang,Baolin Yan,Jianmin Luo,Xintai Su,Fan Yue
Graphical It's a vacancy-rich world ! During the liquid-nitrogen quenching process, the isolated O atoms on the TiO 2 surface are partially frozen and lose the opportunity to return the crystallographic sites, leaving abundant oxygen vacancy on the surface. The oxygen vacancy-rich TiO 2 prepared via liquid-nitrogen quenching exhibited outstanding advantages on photocatalytic H 2 evolution. Development of novel methods to obtain highly active catalysts for photocatalytic hydrogen evolution is desired. This work reports a facile preannealing-quenching strategy to synthesize oxygen vacancy-rich anatase TiO 2 hollow spheres. TiO 2 hollow spheres are first synthesized via a versatile kinetics-controlled coating method and then subjected to high temperature preannealing followed by rapid quenching in liquid-nitrogen (−196 °C). The as-quenched samples appear light grey suggesting the presence of abundant surface oxygen vacancies, which are subsequently confirmed by the comprehensive analyses of XRD, XPS and EPR spectra. The oxygen vacancies induced by quenching process are proved to have promoted the light adsorption and inhibited the recombination of photo-induced charges for TiO 2 hollow spheres, which obviously improve the photocatalytic performance of those samples. The results showed that the TiO 2 hollow spheres quenched at 500 °C exhibited a robust stability and the most excellent photocatalytic performance for hydrogen evolution (413.5 μmol h −1 ) over other quenched samples and it displayed 1.51 times higher performance than that of samples normally cooled at 500 °C (273.7 μmol h −1 ). Herein, this liquid-nitrogen quenching strategy presented here provides an effective route for the synthesis of high-performance TiO 2 for water splitting and have a promising prospect in the other application.
研究领域:
材料科学
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催化
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纳米技术
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能源转换
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DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
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IF 9.446
Jun Xiao,Weiyi Yang,Qi Li
Bi quantum dots were deposited onto rutile TiO 2 nanoparticles by a one-pot, solvent-thermal process to create the Bi/TiO 2 (rutile) heterojunction photocatalyst. Due to the specific semimetal property of Bi, a metal to semiconductor transition occurred for Bi quantum dots, which endowed them with the hole trapping capability to enhance the charge carrier separation in rutile TiO 2 and eliminate the need of sacrificial agents for the consumption of photogenerated holes in photocatalytic reduction process. The Bi/TiO 2 (rutile) heterojunction photocatalyst demonstrated an efficient photocatalytic bromate reduction under visible light illumination without the addition of sacrificial agents in the reaction solution, and it could be easily regenerated for reuse. Different with previously reported noble/transition metal modifications as the electron trapping center, this study demonstrated a novel material design strategy of the introduction of hole trapping centers to create photocatalysts with strong photocatalytic reduction capabilities, which could be readily adopted for a broad range of technical applications.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
Nanoscale
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2015
·Vol. 7
·期 33
·13888-13897
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IF 7.394
Jingling Yang,Qili Wu,Shiman He,Jing Yan,Jianying Shi,Jian Chen,Mingmei Wu,Xianfeng Yang
A TiO2 film has been facilely grown on a Ti foil via a general and simple acid vapor oxidation (AVO) strategy. Based on detailed characterization by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we found that the TiO2 film was composed of anatase nanoarrays highly oriented along their <001> direction, resulting in a large exposed {001} top surface on the film. The growth mechanism based on a topotactic transformation was proposed according to a careful study of time-dependent experimental results. Resulting from the evaluation of photocatalytic performance compared with a commercial TiO2 photocatalyst (Degussa P25), the as-prepared oriented anatase TiO2 film showed higher efficiency for degradation of atrazine and acid orange II (AOII). The performance of photocatalysis is highly relevant to the preferential orientation. The efficient photocatalysis could be attributed to the highly reactive {001} facets on the anatase nanoarrays with super-hydrophilicity.
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2020
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IF 6.551
Caifeng Zhao,Yahui Yang,Lin Luo,Sai Shao,Yiji Zhou,Ying Shao,Faqi Zhan,Jian Yang,Yaoyu Zhou
Oxygen vacancies and Ti 3+ defects in anatase TiO 2 have attracted great attention to address the insufficient optical absorption and photoinduced charge-carrier separation in photocatalysis . In this study, we demonstrate a superficial and innovative approach for synthesizing anatase TiO 2 nanoparticles with abundant oxygen vacancies via γ-ray irradiation reduction at room temperature. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) confirm that oxygen vacancies and Ti 3+ defects can be quantitatively and extensively obtained by merely regulating the irradiation dosage. Photoelectrochemical measurements suggest that oxygen vacancies and Ti 3+ defects promoted the separation of electron-hole pairs and then enhanced the photocatalytic degradation performance for organic pollutant. In comparison with TiO 2 (no irradiation), the sample (49.5 kGy irradiation) exhibited a 20.0-fold enhancement in visible-light decomposition of phenol. In addition, the results of scavenge experiments and mechanism analysis revealed that O 2 − are the dominant active species. The excited electrons generated at the conduction band and oxygen vacancy level of TiO 2−x -49.5 conspicuously contributes to generate much more ·O 2 − species. This novel study shows at room temperature, the γ-ray approach of irradiation leads to faster formation and quantification of oxygen vacancies in the semiconductor materials .
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
Materials
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2021
·Vol. 14
·期 11
·2870
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IF 3.623
Jian Di,Haibo Yan,Zhuoyu Liu,Xing Ding
In this paper, we report a novel and simple method for synthesizing the microspheres self-assembled from ultrathin anatase TiO2nanosheets with a high percentage of (001) facets via the hydrolysis process of the single-reagent (potassium fluorotitanate). We then used optical microscopy, scanning electron microscopy, and high-resolution confocal laser Raman spectroscopy to characterize the microspheres generated under different conditions. The study found that the size of the anatase TiO2microspheres synthesized was 0.5–3 μm. As the synthesis time increased, the corroded surface of the microspheres gradually increased, resulting in the gradual disappearance of the edges and corners of the anatase nanosheets. The exposure percentage of the (001) facets of ultrathin anatase nanosheets synthesized for 2 h at 180–200 °C are close to 100%. The microsphere whose surface is completely covered by these anatase nanosheets also has nearly 100% exposed (001) facets. This new anatase nanosheet-based self-assembled microsphere will have great application potential in pollution prevention, environmental protection, and energy fields.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
ACS Applied Nano Materials
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2024
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IF 5.3
Wenlong Mei,Hanhan Lu,Ru Dong,ShanShan Tang,Jinlei Xu
Tetracycline (TC) is one of the most produced and used antibiotics in the world. The accumulation and migration of TC in water bodies cause serious environmental pollution and biological health problems. In this study, three kinds of brookite TiO2 (Ce/BTN) nanophotocatalysts with different Ce doping amounts were synthesized by a one-pot hydrothermal method, which provided an effective way to solve this problem. The chemical and photoelectric properties of nanomaterials were measured by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HRTEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and photoelectrochemical techniques. The results show that after Ce doping, the sample still maintains the brookite crystal form with high crystallinity, and the morphology does not change significantly. However, the impurity energy level can be formed after Ce doping in the brookite TiO2, which reduces the band gap and extends the range of spectral response. The photocatalytic activity of different catalysts was evaluated by degrading TC solutions under simulated visible light. Based on the free radical capture experiment, the effective active species of the catalyst to degrade tetracycline was determined, and the mechanism of photocatalyst degradation was proposed.
研究领域:
环境科学
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材料科学
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光催化技术
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DOI
高影响因子
Environmental Science-Nano
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2019
·Vol. 6
·期 6
·1740-1753
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IF 7.704
Tong Li,Zelin Shen,Yiling Shu,Xuguang Li,Chuanjia Jiang,Wei Chen
Thermal treatment is one of the most common and facile approaches for defect engineering of semiconductor nanomaterials for enhanced photocatalytic activities. Thus far, little is known about how exposed facets, an intrinsic nanomaterial property, may affect defect generation of widely used semiconductor nanomaterials, e.g., titanium dioxide (TiO2). Here, we synthesized two anatase TiO2 materials with different predominantly exposed facets (i.e., {101} and {010} facets, respectively), and manipulated the defects by calcination at 500 °C under an air or argon atmosphere. Through Raman, electron paramagnetic resonance, UV-vis, and X-ray photoelectron spectroscopy analyses, we demonstrated that the change of surface defect content was facet-dependent. Calcination in argon consistently increased the surface defect content for both materials, arising from the dissociation of surface oxygen atoms and removal of surface hydroxyl groups. In comparison, calcination in air decreased the surface defect content of the {101}-faceted material but increased that of the {010}-faceted material. This discrepancy was likely because, compared with the {101} facets, the {010} facets can lose surface oxygen more easily and contain a greater amount of surface hydroxyl groups. Accordingly, for the {010} facets the formation of surface defects can outcompete the annealing of defects, which occurs during thermal treatment in air. Photoluminescence analysis, electrochemical impedance spectroscopy and photocatalytic activities towards bisphenol A, Rhodamine B and hexavalent chromium degradation were consistent with the changes of defect content of the TiO2 materials, corroborating that the altered defect properties were mainly associated with surface rather than bulk defects. The findings of this work may have important implications for photocatalyst design via defect engineering.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
APPLIED SURFACE SCIENCE
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2015
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IF 2.711
Liang Chu,Zhengfei Qin,Qiaoxia Zhang,Wei Chen,Jian Yang,Jianping Yang,Xing⿿ao Li
Mesoporous anatase TiO 2 microspheres with interconnected nanostructures meet both large surface area and connected-structure for electron transfer as ideal nano/micromaterials for application in solar cells, energy storage, catalysis, water splitting and gas sensing. In this work, mesoporous anatase TiO 2 microspheres consisting of interconnected nanoparticles were synthesized by template-free, one-step fast solvothermal process, where urea was used as capping agent to control phase and promote oriented growth. The morphology was assembled by nucleation-growth-assembly-mechanism. The mesoporous anatase TiO 2 microspheres with interconnected nanoparticles were further utilized as efficient photoelectrodes of dye-sensitized solar cells (DSSCs), which were beneficial to capacity of dye loading and charge transfer. The power conversion efficiency (PCE) based on the optimized thickness of TiO 2 photoelectrodes was up to 7.13% under standard AM 1.5 G illumination (100 mW/cm 2 ).
研究领域:
材料科学
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能源科学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2017
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IF 3.582
Zuohua Liu,Yujie Zheng,Tingting Gao,Jing Zhang,Xuefeng Sun,Guowei Zhou
In this study, anatase TiO 2 nanorods with exposed high-energy {100} and {001} facets and low-energy {101} facets were fabricated in the presence of surfactants cetyltrimethylammonium bromide , didecyldimethylammonium bromide, and ammonia via a facile hydrothermal method without the erosive reagent hydrofluoric acid . The particle size and morphology were mainly tuned by regulating the hydrothermal temperature. When the temperature was increased from 150 °C to 180 °C and 200 °C, the length of the nanorods decreased from 700-1000 nm to 400–500 nm and 100–200 nm, respectively. Concurrently, the edges and tops of the truncated tetragonal pyramid of the TiO 2 nanorods became blurry and flattened. The synthesized typical TiO 2 nanorods were then used as photocatalysts , and their performance during the direct generation of H 2 from water was evaluated. The TiO 2 nanorods obtained at 150 °C successfully produced high amounts of H 2 evolution (281.36 μmol) in the presence of methanol as a sacrificial agent under ultraviolet light irradiation for 4 h. The outstanding photocatalytic activity of the nanorods was mainly ascribed to the formation of surface heterojunctions in the edges and corners between adjacent high-energy {001} or {100} facets and low-energy {101} facets. The formed heterojunctions could facilitate charge separation through preferential carrier flow toward the specific facets.
研究领域:
材料科学
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能源科学
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DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 7
·1122
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IF 5.719
Yong Li,Ming-Qing Zhang,Yan-Fang Liu,Ya-Xun Sun,Qing-Hua Zhao,Tian-Lu Chen,Yuan-Fu Chen,Shi-Feng Wang
Photocatalytic degradation is one of the most promising emerging technologies for environmental pollution control. However, the preparation of efficient, low-cost photocatalysts still faces many challenges. TiO2is a widely available and inexpensive photocatalyst material, but improving its catalytic degradation performance has posed a significant challenge due to its shortcomings, such as the easy recombination of its photogenerated electron–hole pairs and its difficulty in absorbing visible light. The construction of homogeneous heterojunctions is an effective means to enhance the photocatalytic performances of photocatalysts. In this study, a TiO2(B)/TiO2(A) homogeneous heterojunction composite photocatalyst (with B and A denoting bronze and anatase phases, respectively) was successfully constructed in situ. Although the construction of homogeneous heterojunctions did not improve the light absorption performance of the material, its photocatalytic degradation performance was substantially enhanced. This was due to the suppression of the recombination of photogenerated electron–hole pairs and the enhancement of the carrier mobility. The photocatalytic ability of the TiO2(B)/TiO2(A) homogeneous heterojunction composite photocatalyst was up to three times higher than that of raw TiO2(pure anatase TiO2).Keywords:homogeneous heterojunctions;photocatalyst;bronze TiO2;anatase TiO2;photocatalytic degradation
研究领域:
材料科学
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环境科学
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化学
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PubMed
高影响因子
危险品化学品经营许可证（带存储）