APPLIED CATALYSIS B-ENVIRONMENTAL
·
2014
·
IF 6.007
Peng Wang,Danzhen Li,Jing Chen,Xiaoyun Zhang,Jiangjun Xian,Xue Yang,Xiuzhen Zheng,Xiaofang Li,Yu Shao
In this paper, a facile and green method was employed to synthesize CdSe quantum dots (QDs)-modified TiO 2 . It exhibited much higher photocatalytic activities than both TiO 2 and bulk CdSe-modified TiO 2 on degrading malachite green (MG) aqueous solution under visible light irradiation. The vital role that quantum size effect of CdSe QDs plays in enhancing photocatalytic properties of CdSe QDs-modified TiO 2 is discussed in detail for the first time. Due to the more negative conduction band potentials of CdSe QDs than that of bulk CdSe, the electron transfer rate from CdSe QDs to TiO 2 is much faster than that from bulk CdSe to TiO 2 , which would be beneficial for an efficient charge carrier's separation. As a result, more quantities of active species (O 2 • − , H 2 O 2 , •OH) are generated during the photocataltytic reaction in CdSe QDs-modified TiO 2 system. This work could not only provide a facile and green strategy to fabricate semiconductor QDs-modified TiO 2 photocatalyst but also contribute to a deeper understanding of the specific role of semiconductor QDs during the photocatalytic reaction process.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Wei Wang,Jiaojiao Fang,Hu Chen
Mesoporous materials offer attractive routes for designing photocatalysts with nano-confined structures, high activities, and recyclability. Here we take the core-shell and mesoporous SiO 2 nanoparticles as the template for the in situ synthesis of nano-confined g-C 3 N 4 with controllable structures and quantum size effects by varying the precursor species and concentrations. Results indicate that decrease the cyanamide, the precursor, concentration will improve the specific surface area, adsorption ability, and quantum size effect of the final photocatalysts. Cyanamide aqueous solution with a weight ratio of 50.0 wt% results in the most active photocatalyst containing 31.17 wt% of the confined g-C 3 N 4 with a tetracycline degradation rate of 6.63 times higher than that of the cyanamide-derived bulk g-C 3 N 4 (C) under the xenon lamp irradiation. Replacing the cyanamide with urea can further improve the photocatalytic activity even the more active SiCN(U10) contains only 12.47 wt% of the confined g-C 3 N 4 . The improved photocatalytic activity is resulted from the synergistic effects of the high adsorption ability, low aggregation, enhanced quantum size effect, and more exposed active sites. The present study gives new sight on improving the aqueous phase recyclability of the few-layered and high-reactive g–C 3 N 4 –based photocatalysts, and may promote its industrial application process.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
·
IF 5.816
Qing Shi,Hantao Liu
The hydrogen evolution reaction (HER) is a key step for producing hydrogen by water electrolysis , and an economical, facile and environment friendly method of fabricating catalysts for HER is urgent and essential. In this work, we design a high efficient and stable HER catalyst though a simple adsorption and pyrolysis method. The fabricated catalyst presents ruthenium (Ru) quantum dots (QDs) uniformly distributes on the carbon nanofibers (CNF) with a three dimensional (3D) networks structure (Ru@CNF). By means of quantum size effect of Ru QDs and the 3D networks structure of the carbon nanofibers, the former is beneficial to provide more catalytic active sites and the latter is in favour of electron transport . The sample Ru@CNF exhibits a low overpotential of 20 mV at a current density of 10 mA cm −2 and Tafel slope of 31 mV dec −1 in 1 M KOH, which is better than that of Pt/C (28 mV and 36 mV dec −1 ), and most of reported Ru-based and transition metal catalysts . Furthermore, it exhibits robust stability when testing at an overpotential of 75 mV for 24 h. Therefore, this work provides a low-cost, simple and feasible method for fabricating HER catalyst, which possesses commercial application prospect in the field of producing hydrogen by water electrolysis.
研究领域:
材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2021
·Vol. 32
·期 2
·2113-2126
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IF 2.478
Li Xinxin,Xu Jinku
The widespread application of white light-emitting diodes makes us surrounding by plenty of blue-rich light, promoting the development of blue-light-blocking filters because blue light between 415 and 455 nm wavelength can cause light damage to the retina cells. While longer wavelength blue light is also essential to trigger physiological responses, which puts forward higher requirements for the precise blue-light-blocking ability of the filters. In this paper, CdS quantum dot (QD) with strong absorption in the blue region was synthesized and its size was regulated by extended reaction time. Polymerizable molecule was chemically grafted on CdS surface and then copolymerized with methyl methacrylate (MMA) monomer for transparent films with a narrow absorption transition band (wavelength span from 0.05 to 0.8 T max ) about 20 nm and tunable cut-off wavelength at 0.05 T max from 436.9 to 447.8 nm due to quantum size effect of CdS QD. This provides a possibility for more accurate adjustment of the blue-light-blocking performance, minimizing the harmful visual damage of short-wave blue light and preserving the beneficial physiological effects of long-wave blue light.
研究领域:
材料科学
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光学
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生物医学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2025
·
IF 5.1
Yichi Zhong,Jian Huang,Hongyu Yang,Zhanpeng Wang,Kun Qian,Jingzhou Li,Hongxing Dong,Long Zhang
All-inorganic cesium lead bromide zero-dimensional perovskite Cs4PbBr6 is highly valued for its excellent photoelectric conversion efficiency and exceptional stability. However, its application value in the visible light optical field is limited due to large bandgap and strong ionic and covalent bonds in the crystal structure, which inhibit photon emission in the visible light spectrum. Nonetheless the easily convertible properties among perovskite derivatives bring new opportunities. This study is the first to report the transformation of Cs4PbBr6 nanocrystals into CsPbBr3 nanocrystals, which then grow into nanowires and eventually form micrometer-scale optical microcavities. This innovative approach provides a novel strategy for the fabrication of perovskite micro-nano lasers and strengthens the connections among various perovskite derivatives. The nanowires exhibit excellent quantum size effects and are microdevices with polarized photoluminescence emission capability. Meanwhile, the large-sized microrods exhibit perfect lasing performance with low threshold ~34 μJ cm-2 and high Q-factor ~1229. These high-quality performances make Cs4PbBr6 nanocrystals have significant potential in diverse fields such as optical communication, biomedical applications, photonics and optoelectronics.
研究领域:
材料科学
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光学工程
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光电子学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2019
·
IF 4.309
Lina Lin,Yanling Ma,Jianbo Wu,Fei Pang,Jianping Ge,Song Sui,Yefeng Yao,Ruijuan Qi,Yan Cheng,Chun-gang Duan,Junhao Chu,Rong Huang
Colored titanium dioxide (TiO2) nanocrystals have been studied intensively in recent years due to their substantial solar-driven photocatalytic activities. Because of the scarcity of information correlated among atomic structure, electronic structure, and photocatalytic property from isolated nanoparticles, the origin of photocatalytic activity of colored TiO2 from microscopic and electronic level remains intensely debated. Here we demonstrated the origin of photocatalytic activity in Ti4+/Ti3+ core–shell TiO2 nanocrystals mainly by a combination of high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), and photo-Kelvin probe force microscopy (KPFM). The thickness of the Ti3+ shell layer increases with the annealing temperature, meanwhile the O/Ti atomic ratio of the outermost layer decrease. The differences in interplanar spacing between the surface and the subsurface generate strain effect, which increase carrier mobility and ultimately improve catalytic performance. Quantum size effect and specific surface area also have a big impact on catalytic performance. A prerequisite is to keep a good balance between the Ti4+/Ti3+ core–shell structure and the particle size to optimize its photocatalytic properties. By employing Au as a reference, we were able to estimate the Fermi levels of TiO2 before and after illumination. The amplitude of the Fermi level upshift unambiguously relates with the photocatalytic activity. The largest Fermi level upshift under illumination means generating the most efficient photoinduced carries to perform a highly catalytic reaction, carried out by optimizing the electronic structure with appropriate oxygen vacancies. But too many oxygen vacancies increase the recombination center and reduce the concentration of photoinduced electrons, which can also be observed from the photo-KPFM result.
研究领域:
材料科学
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纳米技术
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表面科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Dian Wang,Tongtong Yin,Yanhua Zhang,Fazhi Xie,Xianhuai Huang,Weihua Li,Wenshou Zou,Qishu Qu
The TiO 2 nanoclusters were modified into the pores of silica core-shell particles (SiO 2 @ d SiO 2 ) by the sol-gel method, and the loading amount reached 47%. Based on the Ostwald ripening theory, by simply extending the reaction time, a part of the TiO 2 in the pores of the shell was dissolved and then re-deposited on the outer surface of the shell to form a TiO 2 layer. Using this method, TiO 2 crystalline grains of different sizes were obtained simultaneously inside and outside the shell of silica core-shell spheres. Small-sized crystalline grains were located in the pores of the shell, and they had a strong quantum size effect. The large crystalline grains were located in the TiO 2 layer on the outer surface of the shell of SiO 2 @ d SiO 2 . Due to the formation of larger-sized crystalline grains, the recombination probability of photogenerated electron-hole pairs was reduced. When used as photocatalysts for the degradation of Rhodamine B under UV irradiation, the catalytic activity of SiO 2 @ d SiO 2 @TiO 2 was 5.4 times higher than that of the commercial P25 TiO 2 photocatalyst.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2020
·
IF 3.557
Yue Liu,Song Wei,Gang Wang,Junye Tong,Jing Li,Daocheng Pan
In previous reports of the literature, ZnO nanoparticles were unexceptionally used as the electron transportation material in highly efficient CdSe-based quantum dot light-emitting diodes (QD-LEDs). However, as an amphoteric oxide, ZnO nanoparticles are chemically unstable in air. Here, we utilize quantum-sized SnO2 nanoparticles as the electron transportation layer (ETL) of CdSe-based QD-LEDs. Decreasing the size of SnO2 nanoparticles will upshift the conduction band from −4.50 to −3.84 eV based on the quantum size effect, which is beneficial to facilitate electron injection into the QD emitting layer. Our investigations show that QD-LEDs based on quantum-sized SnO2 nanoparticles exhibit comparable electroluminescence properties and higher stability in contrast to ZnO nanoparticle-based QD-LEDs, demonstrating that small-sized SnO2 nanoparticles have a bright prospect due to the ETL in QD-LEDs.
研究领域:
材料科学
·
光电学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SYNTHETIC METALS
·
2014
·
IF 2.222
Shuai Yan,Siwei Yang,Lin He,Caichao Ye,Xun Song,Fang Liao
In this paper, poly( o -phenylenediamine) quantum dots (PoQDs) with amorphous structures were synthesized via a simple hydrothermal treatment. The size of PoQDs can be easily controlled by changing the reaction time. All these quantum dots show excellent photoluminescent (PL) performance. The p– π * transition between N and conjugated system in PoQDs increased the quantum yield significantly. Further experiments suggested the existence of quantum size effect in amorphous structures for the first time. The controllable PL performance were closely related to the significant quantum size effect. What’s more, these PoQDs were low cost and have high anti-jamming performance, good stability and application perspective of fluorescent bio-imaging.
研究领域:
材料科学
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光学
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2017
·
IF 4.233
Fangyan Liu,Hai Su,Long Jin,Haitao Zhang,Xiang Chu,Weiqing Yang
The ultrafine Co 3 O 4 nanoparticles are successfully prepared by a novel solvothermal–precipitation approach which exploits the supernatant liquid of Co 3 O 4 nanoflake micropheres synthesized by solvothermal method before. Interestingly, the water is only employed to obtain the ultrafine nanoparticles in supernatant liquid which was usually thrown away before. The microstructure measurement results of the as-grown samples present the homogeneous disperse ultrafine Co 3 O 4 nanoparticles with the size of around 5–10 nm. The corresponding synthesis mechanism of the ultrafine Co 3 O 4 nanoparticles is proposed. More importantly, these ultrafine Co 3 O 4 nanoparticles obtained at 250 °C show the highest specific capacitance of 523.0 F g −1 at 0.5 A g −1 , 2.6 times that of Co 3 O 4 nanoflake micropheres due to the quantum size effect . Meanwhile, the sample annealed under 350 °C possesses the best cycling stability with capacitance retention of 104.9% after 1500 cycles. These results unambiguously demonstrate that this work not only provides a novel, facile, and eco-friendly approach to prepare high-performance Co 3 O 4 nanoparticles electrode materials for supercapacitors but also develops a widely used method for the preparation of other materials on a large scale.
研究领域:
材料科学
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能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 21
·12446-12454
·
IF 3.108
Hui Zhang,Rong Wu,Hong Xu,Fan Li,Shuo Wang,Jinshu Wang,Tingting Zhang
This paper reports first on the novel synthesis of hierarchical tin dioxide (SnO2) porous microspheres in the absence of a template using a simple spray reaction technique and annealing at 500–800 °C. The SnO2 microspheres obtained are tetragonal phase and approximately 2.2–2.7 μm in diameter, and they consist of 6.7–23.1 nm crystallites and possess hierarchical pores and Brunauer–Emmett–Teller (BET) surface areas of up to 55 m2 g−1. Using ultraviolet-visible absorption spectra analysis, it is found that SnO2 crystallites demonstrate a quantum size effect, resulting in a widening of the band gap of the SnO2 spheres. This band gap can be tuned from 3.99 eV (800 °C) to 4.26 eV (600 °C) by varying the annealing temperature. Using separated SnO2 porous spheres as the scattering layer of the photoanode for dye sensitized solar cells (DSSCs), the solar light-electricity conversion efficiency (maximum: 6.0%) is increased by up to 31.9% and 28.2% compared to cells using a commercial SnO2 powder and P25 nanopowder as the scattering layers, respectively, under the same conditions.
研究领域:
材料科学
·
能源技术
·
纳米科技
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2013
·Vol. 5
·期 24
·12335-12341
·
IF 6.233
Songping Wu,Zhuolin Wang,Xin Ouyang,Zhiqun Lin
Size-tunable crystalline core–crystalline shell Zn2GeO4 nanorods were synthesized via a facile hydrothermal reaction. High purity Zn2GeO4 nanorods were obtained at pH = 7. The length of Zn2GeO4 nanorods (L = 50–100 nm) can be controlled through a one-step process, while micro-sized nanorods with an aspect ratio of the length to the diameter of 10 were yielded in a two-step process. The single crystalline nature of Zn2GeO4 nanorods with a core–shell structure was verified by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) measurements. The Raman study revealed that there is no oxygen defect in Zn2GeO4 nanocrystals, suggesting that photoluminescence emission of Zn2GeO4 can be attributed to the presence of the interstitial Zn defect in Zn2GeO4 nanocrystals. As the diameter of nanorods decreased, the excitation and emission peaks appeared to be redshifted due to the quantum size effect.
研究领域:
材料科学
·
纳米技术
·
材料的光学性质
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）