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1,304 results on '"Qian, Guodong"'

359. An Ideal Molecular Sieve for Acetylene Removal from Ethylene with Record Selectivity and Productivity

Author

Li, Bin, primary, Cui, Xili, additional, O'Nolan, Daniel, additional, Wen, Hui‐Min, additional, Jiang, Mengdie, additional, Krishna, Rajamani, additional, Wu, Hui, additional, Lin, Rui‐Biao, additional, Chen, Yu‐Sheng, additional, Yuan, Daqiang, additional, Xing, Huabin, additional, Zhou, Wei, additional, Ren, Qilong, additional, Qian, Guodong, additional, Zaworotko, Michael J., additional, and Chen, Banglin, additional

Published
2017
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371. Nano Anatase TiO2Quasi-Core–Shell Homophase Junction Induced by a Ti3+Concentration Difference for Highly Efficient Hydrogen Evolution

Author

Yu, Siqi, Han, Bing, Lou, Yunchao, Qian, Guodong, and Wang, Zhiyu

Abstract

The fabrication of heterojunctions or homojunctions between semiconductors is a controllable strategy to facilitate charge separation in photocatalysis. The homophase junctions exhibit atomic-level contact for the fast-speed charge transfer via inducing the built-in electric fields. Herein, a new concept of TiO2quasi-core–shell homophase junction induced by a Ti3+concentration difference for remarkably enhancing photocatalytic activity is proposed. Nano anatase TiO2quasi-core–shell homophase junctions are constructed between the interior with high Ti3+concentration (quasi-core) and the surface with no detected Ti3+(quasi-shell). Diverse Ti3+concentration differences are obtained via regulating the mass ratio of the Ti source. The nano anatase TiO2quasi-core–shell homophase junctions exhibit improved photocatalytic hydrogen evolution compared with commercial anatase nanoparticles. To be specific, the maximum hydrogen evolution rate of 50.02 mmol/h/g is 25.4 times superior to that of commercial anatase nanoparticles under solar illumination. Besides, the photocatalytic activity remains stable (H2evolution rate of 49.21 mmol/h/g, activity loss of <2%) after five cycles of catalytic test. The promoted photocatalytic activities are ascribed to the constitution of a built-in electrical field between the quasi-shell and quasi-core induced by the band bending, which accelerates the spatial charge separation and suppresses the recombination of carriers. Moreover, the atomic-level contact at the homophase junction interface provides smooth channels for carrier transfer, resulting in more effective separation and transfer of photogenerated electrons and holes. The synthesis of nano anatase TiO2quasi-core–shell homophase junctions provides new insights into the efficient separation and transfer of photogenerated carriers for photocatalytic applications.

Published
2020
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372. High‐Efficiency Photocatalysis of Self‐Hydroxylated TiO2 Nanocrystals for Water Splitting.

Author

Yu, Siqi, Fan, Chenyao, Han, Bing, Qian, Guodong, and Wang, Zhiyu

Subjects
PHOTOCATALYSIS, NANOCRYSTALS, HYDROGEN as fuel, ACTIVATION energy, LIGHT absorption, HYDROGEN evolution reactions, TRANSPORTATION rates, PHOTOELECTROCHEMISTRY
Abstract

Herein, a facile and controllable strategy to synthesize self‐hydroxylated TiO2 nanocrystals with promoted photocatalytic activity in hydrogen evolution is demonstrated. Various colors (yellow, light yellow, blueish gray and gray) in appearance are induced by controlling the molar ratio of titanium source to oxidant during the hydrothermal treatment. Compared with commercial P25 TiO2 nanoparticles, the as‐obtained self‐hydroxylated TiO2 nanocrystals exhibit better photocatalytic performance in H2 evolution. Specifically, the maximum hydrogen evolution rate under solar light illumination (10.0 mmol/h/g) is 4.6 times superior to that of P25. The characterization results confirm the presence of abundant hydroxyls resulting from the hydrothermal treatment, which decreases the recombination rate of carriers and the energy barrier of hydrogen formation while facilitates light absorption for promoting photocatalytic performance. [ABSTRACT FROM AUTHOR]

Published
2019
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373. Phase and morphology evolution of luminescent NaLnF4 (Ln = La to Yb) micro-crystals: understanding the ionic radii and surface energy-dependent solution growth mechanism.

Author

Sun, Xinwen, Wang, Xinwei, Chen, Bing, Zhao, Feiyu, Xu, Xiuxia, Ren, Kai, Lu, Yunhao, Qiao, Xvsheng, Qian, Guodong, and Fan, Xianping

Subjects
YTTERBIUM, RARE earth metals, LUMINESCENCE, MORPHOLOGY, SURFACE energy, RADIUS (Geometry), BIOLOGICAL evolution
Abstract

Lanthanide (Ln)-based NaLnF4 micro-crystals (MCs) exhibit great advantages and strong feasibility for integration into micron-sized photonic devices. However, there is still a lack of thermodynamic understanding of the solution growth mechanisms of NaLnF4 MCs. Herein, we report the preparation of hexagonal NaLnF4 MCs with various morphologies (rod-, disk- and flake-like) and crystal sizes (100 nm to 10 μm) via a hydrothermal route. The morphologies and sizes of NaLnF4 MCs were revealed to be highly dependent on the ionic radius of different Ln3+ ions. We have proposed a ligand-adsorption-driven oriented growth model and a surface energy dominant nucleation model to interpret the above phenomena. First, the citrate (Cit3−) adsorption on the {101¯0} lattice plane primarily leads to different morphologies of NaLnF4 MCs. Second, different surface energies are required for nucleation and are responsible for crystal size evolution from NaYbF4 to LaF3. Third, alternative phase types from NaLnF4 to LnF3 are related to the Ln–F bond energy and Goldschmidt's law of crystal chemistry. In addition, the surface ligand removal is beneficial for the luminescence enhancement of NaLnF4 MCs. These results provide a thermodynamic understanding for researchers to develop NaLnF4 MCs with targeted morphology and size. [ABSTRACT FROM AUTHOR]

Published
2019
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375. Photo-induced electron transfer in a metal–organic framework: a new approach towards a highly sensitive luminescent probe for Fe3+.

Author

Cui, Yuanjing, Yue, Dan, Huang, Yike, Zhang, Jun, Wang, Zhiyu, Yang, Deren, and Qian, Guodong

Subjects
LUMINESCENT probes, METAL-organic frameworks, CHARGE exchange, DETECTION limit
Abstract

A Co-based mixed-ligand metal–organic framework (MOF), ZJU-109, is reported by utilizing 6-(4-pyridyl)-terephthalic acid (H2pta) and 4,4′-bis(imidazolyl)biphenyl (4,4′-bimbp) as double linkers. By tuning the d-PET process between ligands 4,4′-bimbp and H2pta, a fluorescent turn-on sensor for Fe3+ with a detection limit as low as 0.053 μM has been demonstrated. [ABSTRACT FROM AUTHOR]

Published
2019
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376. Near-infrared-emissive metal–organic frameworks.

Author

Zou, Danna, Zhang, Jun, Cui, Yuanjing, and Qian, Guodong

Subjects
METAL-organic frameworks, ATTENTION
Abstract

Emerging as a promising novel material, near-infrared-emissive metal–organic frameworks (NIR-emissive MOFs) have drawn much attention for their unique properties. Here, we demonstrate recent advancements in enhancing the NIR emission performance of MOFs as well as their appealing applications in bio-imaging, sensing and barcoding. The present challenges are briefly concluded and the possible future prospects are discussed. [ABSTRACT FROM AUTHOR]

Published
2019
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377. Multi‐phase glass‐ceramics containing CaF2: Er3+ and ZnAl2O4:Cr3+ nanocrystals for optical temperature sensing.

Author

Wadhwa, Abhishek, Wang, Changjian, Wang, Chenhao, Ma, Ronghua, Qiao, Xvsheng, Fan, Xianping, and Qian, Guodong

Subjects
NANOCRYSTALS, GLASS-ceramics, QUENCHING (Chemistry), PHOTON upconversion, OXYFLUORIDES, RARE earth metals
Abstract

Oxyfluoride transparent glass‐ceramics (GC) containing CaF2 and ZnAl2O4 nanocrystals have been fabricated with melt‐quenching method. By carrying out the heat treatment of the precursor glass (PG), Er3+ and Cr3+ were selectively partitioned into CaF2 and ZnAl2O4 nanocrystals, respectively. The obtained multi‐phase GC exhibited strong upconversion (UC) fluorescence of Er3+ as well as intense down‐conversion (DC) fluorescence of Cr3+. Under 980 nm excitation, the green UC fluorescence of Er3+ due to 2H11/2,4S3/2 → 4I15/2 transition and the red DC fluorescence lifetime of Cr3+ due to 2E, 4T2 → 4A2 transition were found to be highly dependent on the temperature and makes them possibly suitable for Optical Thermometry. With least‐square fitting methods, the FIR of Er3+ from thermally coupled energy states (2H11/2 and 4S3/2) produced maximum temperature sensing sensitivity values of 0.33% K−1 at 437 K and 0.36% K−1 at 267 K, respectively. Similarly, fluorescence lifetime of Cr3+ attributed to the parity forbidden (2E → 4A2) and spin allowed (4T2 → 4A2) produced the maximum temperature sensor sensitivity value equal to 0.67% K−1 at 535 K. [ABSTRACT FROM AUTHOR]

Published
2019
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388. A series of multifunctional coordination polymers based on terpyridine and zinc halide: second-harmonic generation and two-photon absorption properties and intracellular imaging

Author

Su, Jian, primary, Zhang, Jun, additional, Tian, Xiaohe, additional, Zhao, Meng, additional, Song, Tao, additional, Yu, Jiancan, additional, Cui, Yuanjing, additional, Qian, Guodong, additional, Zhong, Hong, additional, Luo, Lei, additional, Zhang, Yujin, additional, Wang, Chuankui, additional, Li, Shengli, additional, Yang, Jiaxiang, additional, Zhou, Hongping, additional, Wu, Jieying, additional, and Tian, Yupeng, additional

Published
2017
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