38 results on '"Qiao Zhang"'
Search Results
2. Integrating a Nanowire Laser in an on-Chip Photonic Waveguide
- Author
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Ruixuan Yi, Xutao Zhang, Fanlu Zhang, Linpeng Gu, Qiao Zhang, Liang Fang, Jianlin Zhao, Lan Fu, Hark Hoe Tan, Chennupati Jagadish, and Xuetao Gan
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Mechanical Engineering ,General Materials Science ,Bioengineering ,General Chemistry ,Condensed Matter Physics - Abstract
We report a simple and facile integration strategy of a laser source in passive photonic integrated circuits (PICs) by deterministically embedding semiconductor nanowires (NWs) in waveguides. InP NWs laid on a SiN slab are buried by a polymer layer which also acts as an electron-beam resist. With electron-beam lithography, hybrid polymer-SiN waveguides are formed with precisely embedded NWs. The lasing behavior of the waveguide-embedded NWs is confirmed, and more importantly, the NW lasing mode couples into the hybrid waveguide and forms an in-plane guiding mode. Multiple waveguide-embedded NW lasers are further integrated in complex photonic structures to illustrate that the waveguiding mode supplied by the NW lasers could be manipulated for on-chip signal processing, including power splitting and wavelength-division multiplexing. This integration strategy of an on-chip laser is applicable to other PIC platforms, such as silicon and lithium niobate, and the top cladding layer could be changed by depositing SiN or SiO
- Published
- 2022
3. The Role of Bismuth in Suppressing the CO Poisoning in Alkaline Methanol Electrooxidation: Switching the Reaction from the CO to Formate Pathway
- Author
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Xuchun Wang, Yu Liu, Xing-Yu Ma, Lo-Yueh Chang, Qixuan Zhong, Qi Pan, Zhiqiang Wang, Xiaolei Yuan, Muhan Cao, Fenglei Lyu, Yaoyue Yang, Jinxing Chen, Tsun-Kong Sham, and Qiao Zhang
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Mechanical Engineering ,General Materials Science ,Bioengineering ,General Chemistry ,Condensed Matter Physics - Abstract
While tuning the electronic structure of Pt can thermodynamically alleviate CO poisoning in direct methanol fuel cells, the impact of interactions between intermediates on the reaction pathway is seldom studied. Herein, we contrive a PtBi model catalyst and realize a complete inhibition of the CO pathway and concurrent enhancement of the formate pathway in the alkaline methanol electrooxidation. The key role of Bi is enriching OH adsorbates (OH
- Published
- 2023
4. Fabricating MAPbI3/MoS2 Composites for Improved Photocatalytic Performance
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Huicheng Hu, Qiao Zhang, Wenhao Guan, Zhenhui Kang, Jianian Chen, Yi Li, Muhan Cao, Haiyu Liu, Qixuan Zhong, Jin Gong, Kangxiao Lv, and Yong Xu
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Materials science ,Charge separation ,Mechanical Engineering ,Halide ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Hydrogen halide ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Photocatalysis ,General Materials Science ,Hydrogen evolution ,0210 nano-technology - Abstract
Although lead halide perovskites are demonstrated to be promising photocatalysts for hydrogen evolution from hydrogen halide splitting, it still remains challenging to fabricate efficient and stabl...
- Published
- 2020
5. Ultrafast Microwave Activating Polarized Electron for Scalable Porous Al toward High-Energy-Density Batteries
- Author
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Kun Rui, Wei Huang, Jixin Zhu, Ying Ding, Hai Li, Huijuan Lin, Qiao Zhang, Feng Xu, and Yan Yan
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business.industry ,Mechanical Engineering ,Bioengineering ,General Chemistry ,Electron ,Surface engineering ,Condensed Matter Physics ,Isotropic etching ,Surface energy ,Corrosion ,Optoelectronics ,General Materials Science ,business ,Polarization (electrochemistry) ,Porosity ,Microwave - Abstract
Chemical etching of metals generally brings about undesirable surface damage accompanied by deteriorated performance. However, new possibilities in view of structured interfaces and functional surfaces can be explored by wisely incorporating corrosion chemistry. Here, an ultrafast route to scalable Al foils with desired porous structures originating from Fe(III)-induced oxidation etching was presented. Coupling with efficient electron polarization involving microwave interaction, straightforward surface engineering is well established on various commercial Al foils within minutes, which can be successfully extended to bulk Al alloys. As a proof-of-concept demonstration, the well-defined porous Al foils featuring regulated surface energy, demonstrate great potential as current collectors in promoting cycling stability, for example, 85.2% reversible capacity sustained after 550 cycles (comparable to commercial Al/C foils), and energy density, that is, approximately 3 times of that by using pristine Al foils for LiFePO4-Li half cells.
- Published
- 2020
6. Revealing the Correlation between Catalytic Selectivity and the Local Coordination Environment of Pt Single Atom
- Author
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Muhan Cao, Yu Liu, Qiao Zhang, Jun Luo, Youyong Li, Mingyu Chu, Yong Xu, Xuchun Wang, Jin Gong, Haiping Lin, and Fangfang Liu
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Chemistry ,Mechanical Engineering ,Coordination number ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Propyne ,Heterogeneous catalysis ,Catalysis ,chemistry.chemical_compound ,Chemical physics ,Atom ,General Materials Science ,0210 nano-technology ,Selectivity - Abstract
Single atom catalysts (SACs) have recently attracted great attention in heterogeneous catalysis and have been regarded as ideal models for investigating the strong interaction between metal and support. Despite the huge progress over the past decade, the deep understanding on the structure-performance correlation of SACs at a single atom level still remains to be a great challenge. In this study, we demonstrate that the variation in the coordination number of the Pt single atom can significantly promote the propylene selectivity during propyne semihydrogenation (PSH) for the first time. Specifically, the propylene selectivity greatly increases from 65.4% to 94.1% as the coordination number of Pt-O increases from ∼3.4 to ∼5, whereas the variation in the coordination number of Pt-O slightly influences the turnover frequency values of SACs. We anticipate that the present work may deepen the understanding on the structure-performance of SACs and also promote the fundamental research in single atom catalysis.
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- 2020
7. Integrated Evaporator for Efficient Solar-Driven Interfacial Steam Generation
- Author
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Shan Lei, Dilong Liu, Bo Li, Fang Qian, Jinxing Chen, Fan Yang, Qiao Zhang, Fenglei Lyu, Rashed Aleisa, Guoxiang Hu, Xuewu Ge, Mozhen Wang, and Yadong Yin
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Materials science ,business.industry ,Mechanical Engineering ,Clean water ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Desalination ,Steam generation ,Water production ,Condensed Matter::Soft Condensed Matter ,Physics::Space Physics ,Thermal ,Astrophysics::Solar and Stellar Astrophysics ,General Materials Science ,Liquid interface ,Astrophysics::Earth and Planetary Astrophysics ,0210 nano-technology ,Process engineering ,business ,Physics::Atmospheric and Oceanic Physics ,Evaporator - Abstract
Solar-driven interfacial steam generation is a promising technique for clean water production because it can minimize thermal loss by localizing solar-to-heat conversion at the air/liquid interface. Here we report an integrated solar evaporator by partially growing 2D polypyrrole microsheets within a melamine foam through chemical vapor polymerization. These microsheets can induce multiple light reflections within the foam, enable omnidirectional light absorption, provide abundant surfaces to promote heat transfer, and achieve spatially defined hydrophobicity to facilitate vapor escape. Meanwhile, the inherent hydrophilicity of the bottom part of the foam promotes spontaneous upward water transport and suppresses heat loss. The composite foam exhibits an excellent apparent evaporation rate of ∼2 kg/(m
- Published
- 2020
8. Ultraminiaturized Stretchable Strain Sensors Based on Single Silicon Nanowires for Imperceptible Electronic Skins
- Author
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Zhibin Shao, Si-Yi Huang, Le He, Jiansheng Jie, Qiao Zhang, Bingchang Zhang, and Xiaohong Zhang
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Silicon ,Materials science ,Strain (chemistry) ,Nanowires ,business.industry ,Mechanical Engineering ,Bioengineering ,Biosensing Techniques ,Equipment Design ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Wearable Electronic Devices ,Humans ,Nanotechnology ,Optoelectronics ,General Materials Science ,0210 nano-technology ,Silicon nanowires ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Miniaturized stretchable strain sensors are key components in E-skins for applications such as personalized health-monitoring, body motion perception, and human-machine interfaces. However, it remains a big challenge to fabricate miniaturized stretchable strain sensors with high imperceptibility. Here, we reported for the first time novel ultraminiaturized stretchable strain sensors based on single centimeter-long silicon nanowires (cm-SiNWs). With the diameter of the active materials even smaller than that of spider silks, these sensors are highly imperceptible. They exhibit a large strain sensing range (45%) and a high durability (10 000 cycles). Their optimum strain sensing ranges could be modulated by controlling the prestrains of the stretchable cm-SiNWs. On the basis of this capability, sensors with appropriate sensing ranges were chosen to respectively monitor large and subtle human motions including joint motion, swallow, and touch. The strategy of applying single cm-SiNWs in stretchable sensors would open new doors to fabricate ultraminiaturized stretchable devices.
- Published
- 2020
9. Bi(OH)3/PdBi Composite Nanochains as Highly Active and Durable Electrocatalysts for Ethanol Oxidation
- Author
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Yong Xu, Tong Zhou, Xiaolei Yuan, Yong Zhang, Fenglei Lyu, Muhan Cao, Yadong Yin, Xiaojing Jiang, Qiao Zhang, Jun Luo, and Jinxing Chen
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Ethanol ,Materials science ,Mechanical Engineering ,Composite number ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Bismuth hydroxide ,General Materials Science ,Ethanol fuel ,0210 nano-technology ,Ethanol oxidation reaction - Abstract
Developing high-performance electrocatalysts for the ethanol oxidation reaction (EOR) is critical to the commercialization of direct ethanol fuel cells. However, current EOR catalysts suffer from h...
- Published
- 2019
10. L-Type Ligand-Assisted Acid-Free Synthesis of CsPbBr3 Nanocrystals with Near-Unity Photoluminescence Quantum Yield and High Stability
- Author
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Muhan Cao, Lu Wang, Youyong Li, Qiao Zhang, Yong Zhang, Di Yang, Qixuan Zhong, Xiaohong Zhang, Yong Xu, Yafeng Xu, Huicheng Hu, and Pengli Li
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Materials science ,Photoluminescence ,Proton ,Ligand ,Mechanical Engineering ,Quantum yield ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Photochemistry ,Oleic acid ,chemistry.chemical_compound ,chemistry ,Nanocrystal ,Oleylamine ,General Materials Science ,0210 nano-technology - Abstract
X-type ligands, for example, the pair of oleylamine (OAm) and oleic acid (OA), have been widely used to prepare CsPbX3 nanocrystals (NCs). However, the proton exchange between coordinated OAm and O...
- Published
- 2019
11. Fabricating MAPbI
- Author
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Wenhao, Guan, Yi, Li, Qixuan, Zhong, Haiyu, Liu, Jianian, Chen, Huicheng, Hu, Kangxiao, Lv, Jin, Gong, Yong, Xu, Zhenhui, Kang, Muhan, Cao, and Qiao, Zhang
- Abstract
Although lead halide perovskites are demonstrated to be promising photocatalysts for hydrogen evolution from hydrogen halide splitting, it still remains challenging to fabricate efficient and stable catalysts. Here MoS
- Published
- 2020
12. Bismuth Oxyhydroxide-Pt Inverse Interface for Enhanced Methanol Electrooxidation Performance
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Mingyu Chu, Yujian Xia, Y. M. Yiu, Fenglei Lyu, Qiao Zhang, Jiatang Chen, Tsun-Kong Sham, Zhiqiang Wang, Miao Xie, Hao Yang, Xuchun Wang, Qixuan Zhong, Lo-Yueh Chang, and Tao Cheng
- Subjects
X-ray absorption spectroscopy ,Materials science ,Absorption spectroscopy ,Mechanical Engineering ,chemistry.chemical_element ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electrochemistry ,Bismuth ,chemistry.chemical_compound ,Adsorption ,chemistry ,X-ray photoelectron spectroscopy ,Chemical engineering ,General Materials Science ,Methanol ,0210 nano-technology ,Methanol fuel - Abstract
Developing efficient Pt-based electrocatalysts for the methanol oxidation reaction (MOR) is of pivotal importance for large-scale application of direct methanol fuel cells (DMFCs), but Pt suffers from severe deactivation brought by the carbonaceous intermediates such as CO. Here, we demonstrate the formation of a bismuth oxyhydroxide (BiOx(OH)y)-Pt inverse interface via electrochemical reconstruction for enhanced methanol oxidation. By combining density functional theory calculations, X-ray absorption spectroscopy, ambient pressure X-ray photoelectron spectroscopy, and electrochemical characterizations, we reveal that the BiOx(OH)y-Pt inverse interface can induce the electron deficiency of neighboring Pt; this would result in weakened CO adsorption and strengthened OH adsorption, thereby facilitating the removal of the poisonous intermediates and ensuring the high activity and good stability of Pt2Bi sample. This work provides a comprehensive understanding of the inverse interface structure and deep insight into the active sites for MOR, offering great opportunities for rational fabrication of efficient electrocatalysts for DMFCs.
- Published
- 2020
13. Giant and Multistage Nonlinear Optical Response in Porphyrin-Based Surface-Supported Metal-Organic Framework Nanofilms
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Qiang Shen, Qiao Zhang, Pengxian You, Jianbo Hu, Hang Zhang, Chun Gu, Zhengbang Wang, and Guoqiang Luo
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Materials science ,business.industry ,Mechanical Engineering ,Bioengineering ,Saturable absorption ,02 engineering and technology ,General Chemistry ,Crystal structure ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Porphyrin ,Optical switch ,chemistry.chemical_compound ,chemistry ,Attenuation coefficient ,Optoelectronics ,Molecule ,General Materials Science ,0210 nano-technology ,Absorption (electromagnetic radiation) ,business ,Excitation - Abstract
Benefitting from the strong intrinsic nonlinear optical (NLO) property of the individual porphyrin molecule, the integration of porphyrin molecules into tightly aligned arrays may lead to intuitively promising high-performance materials of tailorable NLO effect. In order to verify this speculation, we prepare crystalline and highly oriented porphyrin-based surface-supported metal-organic framework nanofilms (SURMOFs) and then characterize their NLO performance. Results reveal that porphyrin-based SURMOFs exhibit the highest saturable absorption (SA) yet recorded with a third-order NLO absorption coefficient up to -10-3 cm/W, about 7 orders stronger than porphyrin solvents in which the porphyrin molecules are disordered, under a certain excitation strength. Further increasing the excitation strength shows that the NLO absorption property of the porphyrin-based SURMOFs can be effectively modulated from SA to reverse saturable absorption, followed by a reemerging SA. The multiple-stage NLO switching is assigned to the interplay of simultaneous one-photon SA, two-photon absorption, and two-photon SA effects. The superior and modulatable NLO property as well as the designable and ordered crystalline structure suggest that porphyrin-based SURMOFs might be employed as a new class of high-performance NLO materials with potential applications in novel optical switches or logic gates to realize the all-optical information process.
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- 2019
14. From Nonluminescent Cs4PbX6 (X = Cl, Br, I) Nanocrystals to Highly Luminescent CsPbX3 Nanocrystals: Water-Triggered Transformation through a CsX-Stripping Mechanism
- Author
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Qixuan Zhong, Qiao Zhang, Linzhong Wu, Yadong Yin, Di Yang, Xu Yong, Huicheng Hu, Shu Jiang, Baoquan Sun, Qipeng Liu, Yun Zhao, and Min Chen
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Photoluminescence ,Stripping (chemistry) ,Chemistry ,Mechanical Engineering ,Quantum yield ,Ionic bonding ,Halide ,Bioengineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Nanocrystal ,Phase (matter) ,General Materials Science ,0210 nano-technology ,Luminescence - Abstract
We report a novel CsX-stripping mechanism that enables the efficient chemical transformation of nonluminescent Cs4PbX6 (X = Cl, Br, I) nanocrystals (NCs) to highly luminescent CsPbX3 NCs. During the transformation, Cs4PbX6 NCs dispersed in a nonpolar solvent are converted into CsPbX3 NCs by stripping CsX through an interfacial reaction with water in a different phase. This process takes advantage of the high solubility of CsX in water as well as the ionic nature and high ion diffusion property of Cs4PbX6 NCs, and produces monodisperse and air-stable CsPbX3 NCs with controllable halide composition, tunable emission wavelength covering the full visible range, narrow emission width, and high photoluminescent quantum yield (up to 75%). An additional advantage is that this is a clean synthesis as Cs4PbX6 NCs are converted into CsPbX3 NCs in the nonpolar phase while the byproduct of CsX is formed in water that could be easily separated from the organic phase. The as-prepared CsPbX3 NCs show enhanced stability a...
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- 2017
15. Bi(OH)
- Author
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Xiaolei, Yuan, Yong, Zhang, Muhan, Cao, Tong, Zhou, Xiaojing, Jiang, Jinxing, Chen, Fenglei, Lyu, Yong, Xu, Jun, Luo, Qiao, Zhang, and Yadong, Yin
- Abstract
Developing high-performance electrocatalysts for the ethanol oxidation reaction (EOR) is critical to the commercialization of direct ethanol fuel cells. However, current EOR catalysts suffer from high cost, low activity, and poor durability. Here we report the preparation of PdBi-Bi(OH)
- Published
- 2019
16. L-Type Ligand-Assisted Acid-Free Synthesis of CsPbBr
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Qixuan, Zhong, Muhan, Cao, Yafeng, Xu, Pengli, Li, Yong, Zhang, Huicheng, Hu, Di, Yang, Yong, Xu, Lu, Wang, Youyong, Li, Xiaohong, Zhang, and Qiao, Zhang
- Abstract
X-type ligands, for example, the pair of oleylamine (OAm) and oleic acid (OA), have been widely used to prepare CsPbX
- Published
- 2019
17. The Synergy between Metal Facet and Oxide Support Facet for Enhanced Catalytic Performance: The Case of Pd–TiO2
- Author
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Youyong Li, Haiping Lin, Yong Xu, Elad Gross, Qipeng Liu, Min Chen, Qiao Zhang, Muhan Cao, and Zeyuan Tang
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Nanostructure ,Materials science ,Oxide ,chemistry.chemical_element ,Bioengineering ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,Metal ,chemistry.chemical_compound ,General Materials Science ,Facet ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,chemistry ,Nanocrystal ,visual_art ,visual_art.visual_art_medium ,0210 nano-technology ,Selectivity ,Palladium - Abstract
The demand for catalyst with higher activity and higher selectivity is still a central issue in current material science community. On the basis of first-principles calculations, we demonstrate that the catalytic performance of the Pd-TiO2 hybrid nanostructures can be selectively promoted or depressed by choosing the suitable shaped Pd and TiO2 nanocrystals. To be more specific, the catalytic activities of Pd nanoparticles enclosed by (100) or (111) facets can be promoted more significantly when dosed on the TiO2(001) than on TiO2(101) under irradiation. Such theoretical prediction has then been further verified by the experimental observations in which the Pd(100)-TiO2(001) composites exhibit the highest catalytic performance toward the activation of oxygen among all the other shaped hybrid nanostructures. As a result, the selection of facets of support materials can provide an extra tuning parameter to control the catalytic activities of metal nanoparticles. This research opened up a new direction for designing and preparing catalysts with enhanced catalytic performance.
- Published
- 2016
18. Hydrogenation Driven Conductive Na2Ti3O7 Nanoarrays as Robust Binder-Free Anodes for Sodium-Ion Batteries
- Author
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Qiao Zhang, Yong Xu, Liang Li, Shidong Fu, and Jiangfeng Ni
- Subjects
Battery (electricity) ,Materials science ,Mechanical Engineering ,Sodium ,chemistry.chemical_element ,Sodium-ion battery ,Bioengineering ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Thermal diffusivity ,01 natural sciences ,0104 chemical sciences ,Ion ,Anode ,chemistry ,Electrical resistivity and conductivity ,General Materials Science ,0210 nano-technology ,Electrical conductor - Abstract
We present a general and rational approach to fabricate highly accessible and affordable sodium-ion battery anodes by engineering three-dimensional hydrogenated Na2Ti3O7 nanoarrays supported on flexible Ti substrates. The hydrogenated Na2Ti3O7 nanoarrays exhibit desirable properties for sodium storage, such as high surface area, high electrical conductivity, and Na(+) diffusivity. The as-obtained nanoarrays demonstrate remarkably stable and robust Na-storage performance when tested as binder-free anodes for sodium-ion battery. They can afford a high reversible (desodiation) capacity of 227 mAh g(-1) and retain a capacity of 65 mAh g(-1) over 10,000 continuous cycles at a high rate of 35 C. Therefore, through this synergy of array architecture and hydrogenation, it is possible to engineer numerous anodes that can reversibly store Na(+) ions in a fast and stable manner.
- Published
- 2016
19. Encapsulated Silver Nanoparticles Can Be Directly Converted to Silver Nanoshell in the Gas Phase
- Author
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Yong Xu, Sui-Dong Wang, Qiao Zhang, Feng Bao, Peipei Yang, Zhongzhi Xie, Baohua Mao, Lei Chen, and Xuchun Wang
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Aqueous solution ,Materials science ,Nanostructure ,Mechanical Engineering ,Nanoparticle ,Bioengineering ,Nanotechnology ,General Chemistry ,Condensed Matter Physics ,Tollens' reagent ,Silver nanoparticle ,Nanoshell ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Reagent ,General Materials Science ,Surface plasmon resonance - Abstract
We report, for the first time, that an encapsulated silver nanoparticle can be directly converted to a silver nanoshell through a nanoscale localized oxidation and reduction process in the gas phase. Silver can be etched when exposed to a mixture of NH3/O2 gases through a mechanism analogous to the formation of aqueous Tollens' reagent, in which a soluble silver-ammonia complex was formed. Starting with Ag@resorcinol-formaldehyde (RF) resin core-shell nanoparticles, we demonstrate that RF-core@Ag-shell nanoparticles can be prepared successfully when the etching rate and RF thickness were well controlled. Due to the strong surface plasmon resonance (SPR) coupling effect among neighboring silver nanoparticles, the RF@Ag nanoparticle showed great SPR and SERS performance. This process provides a general route to the conversion of Ag-core to Ag-shell nanostructures and might be extended to other systems.
- Published
- 2015
20. From Nonluminescent Cs
- Author
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Linzhong, Wu, Huicheng, Hu, Yong, Xu, Shu, Jiang, Min, Chen, Qixuan, Zhong, Di, Yang, Qipeng, Liu, Yun, Zhao, Baoquan, Sun, Qiao, Zhang, and Yadong, Yin
- Abstract
We report a novel CsX-stripping mechanism that enables the efficient chemical transformation of nonluminescent Cs
- Published
- 2017
21. Polymorphic Assembly from Beveled Gold Triangular Nanoprisms
- Author
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Qipeng Liu, Fei Ji, Xiaohui Song, Juyeong Kim, Binbin Luo, Qiao Zhang, Nicole F. Ice, and Qian Chen
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Materials science ,Mechanical Engineering ,Nanoparticle ,Bioengineering ,Geometry ,Nanotechnology ,02 engineering and technology ,General Chemistry ,Geometric shape ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electrostatics ,01 natural sciences ,Bevel ,0104 chemical sciences ,Planar ,General Materials Science ,Triangular prism ,0210 nano-technology ,Anisotropy ,Nanoscopic scale - Abstract
The shape anisotropy of nanoparticle building blocks is of critical importance in determining their packing symmetry and assembly directionality. While there has been extensive research on the effect of their overall geometric shapes, the importance of nanometer morphology details is not well-recognized or understood. Here we draw on shape-anisotropic gold triangular nanoprism building blocks synthesized based on a method we recently developed; besides the "large-scale" triangular prism shape (79.8 nm in side length and 22.0 nm in thickness), the prisms are beveled with their sides convexly enclosed by two flat {100} facets. We engineer the balance between electrostatic repulsion and entropically driven depletion attraction in the system to generate self-assemblies without or with the effect of the nanoscale beveling detail. A conventional, planar honeycomb (p-honeycomb) lattice forms with the triangular basal planes packed on the same plane at low depletion attraction, whereas an unexpected interlocking honeycomb (i-honeycomb) lattice and its "supracrystal" forms are assembled with additional close-paralleling of side facets at high depletion attraction. The i-honeycomb lattice renders all the metallic surfaces in close proximity and leads to a surface-enhanced Raman scattering signal nearly 5-fold higher than that in the p-honeycomb lattice and high sensitivity for detecting the model molecule Rhodamine 6G at a concentration as low as 10
- Published
- 2017
22. High-Temperature Catalytic Reforming of n-Hexane over Supported and Core–Shell Pt Nanoparticle Catalysts: Role of Oxide–Metal Interface and Thermal Stability
- Author
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Selim Alayoglu, Gabor A. Somorjai, Kwangjin An, Nathan Musselwhite, Jae-Youn Shin, and Qiao Zhang
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Materials science ,Mechanical Engineering ,Sintering ,Nanoparticle ,Bioengineering ,General Chemistry ,Condensed Matter Physics ,Catalysis ,Reaction rate ,Catalytic reforming ,Chemical engineering ,Organic chemistry ,General Materials Science ,Thermal stability ,Mesoporous material ,Isomerization - Abstract
Designing catalysts with high thermal stability and resistance to deactivation while simultaneously maintaining their catalytic activity and selectivity is of key importance in high-temperature reforming reactions. We prepared Pt nanoparticle catalysts supported on either mesoporous SiO2 or TiO2. Sandwich-type Pt core@shell catalysts (SiO2@Pt@SiO2 and SiO2@Pt@TiO2) were also synthesized from Pt nanoparticles deposited on SiO2 spheres, which were encapsulated by either mesoporous SiO2 or TiO2 shells. n-Hexane reforming was carried out over these four catalysts at 240-500 °C with a hexane/H2 ratio of 1:5 to investigate thermal stability and the role of the support. For the production of high-octane gasoline, branched C6 isomers are more highly desired than other cyclic, aromatic, and cracking products. Over Pt/TiO2 catalyst, production of 2-methylpentane and 3-methylpentane via isomerization was increased selectively up to 420 °C by charge transfer at Pt-TiO2 interfaces, as compared to Pt/SiO2. When thermal stability was compared between supported catalysts and sandwich-type core@shell catalysts, the Pt/SiO2 catalyst suffered sintering above 400 °C, whereas the SiO2@Pt@SiO2 catalyst preserved the Pt nanoparticle size and shape up to 500 °C. The SiO2@Pt@TiO2 catalyst led to Pt nanoparticle sintering due to incomplete protection of the TiO2 shells during the reaction at 500 °C. Interestingly, over the Pt/TiO2 catalyst, the average size of Pt nanoparticles was maintained even after 500 °C without sintering. In situ ambient pressure X-ray photoelectron spectroscopy demonstrated that the Pt/TiO2 catalyst did not exhibit TiO2 overgrowth on the Pt surface or deactivation by Pt sintering up to 600 °C. The extraordinarily high stability of the Pt/TiO2 catalyst promoted high reaction rates (2.0 μmol · g(-1) · s(-1)), which was 8 times greater than other catalysts and high isomer selectivity (53.0% of C6 isomers at 440 °C). By the strong metal-support interaction, the Pt/TiO2 was turned out as the best catalyst with great thermal stability as well as high reaction rate and product selectivity in high-temperature reforming reaction.
- Published
- 2014
23. Inorganic Micelles as Efficient and Recyclable Micellar Catalysts
- Author
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F. Dean Toste, A. Paul Alivisatos, Gabor A. Somorjai, Xing-Zhong Shu, J. Matthew Lucas, and Qiao Zhang
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Nanostructure ,Materials science ,Chemical engineering ,Mechanical Engineering ,Organic chemistry ,Halogenation ,General Materials Science ,Bioengineering ,General Chemistry ,Catalytic efficiency ,Condensed Matter Physics ,Micelle ,Catalysis - Abstract
An "inorganic micelle" structure that has a hydrophilic cavity and hydrophobic surface has been synthesized. The inorganic micelles possess large surface area and controllable hydrophobic/hydrophilic interface. It shows high catalytic efficiency and great recyclability in the bromination of alcohols. This work suggests that inorganic micelles may be suitable for selective organic syntheses as well as industrial applications and demonstrates the value of translating nanostructure design from organic to inorganic.
- Published
- 2013
24. Permeable Silica Shell through Surface-Protected Etching
- Author
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Qiao Zhang, Yadong Yin, Jianping Ge, and Tierui Zhang
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Materials science ,Silica gel ,Mechanical Engineering ,technology, industry, and agriculture ,Bioengineering ,Core (manufacturing) ,Nanotechnology ,General Chemistry ,Condensed Matter Physics ,Nanomaterials ,chemistry.chemical_compound ,Chemical species ,chemistry ,Chemical engineering ,Etching (microfabrication) ,General Materials Science ,Porosity ,Porous medium ,Sol-gel - Abstract
We describe a "surface-protected etching" strategy that allows convenient conversion of sol-gel derived silica into porous structures. Poly(vinyl pyrrolidone) is used to protect the near surface layer, and NaOH is used to selectively etch the interior of the silica spheres. Etching initially yields porous structures and eventually removes the core to leave behind hollow silica spheres with porous shells. This strategy is useful for constructing core-shell systems where active nanomaterials are embedded in silica shell for enhanced stability against aggregation. We experimentally demonstrate use of the surface-protected etching approach to create openings on silica shells; these openings allow dissolved chemical species to reach embedded catalytic particles to be chemically transformed while the porous shells continue to act as effective barriers against aggregation and loss of activity of the core particles. We also show that, by controlling the extent of etching, it is possible to control the permeation rate of the chemical species through the shells.
- Published
- 2008
25. Scalable Production of Si Nanoparticles Directly from Low Grade Sources for Lithium-Ion Battery Anode
- Author
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Lei Chen, Yue Hu, Jia Zhu, Yan Jin, Qiao Zhang, Bin Zhu, Yanbin Chen, Linqi Zong, and Yingling Tan
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Battery (electricity) ,Materials science ,Nanostructure ,Silicon ,Mechanical Engineering ,Metallurgy ,chemistry.chemical_element ,Nanoparticle ,Bioengineering ,General Chemistry ,Condensed Matter Physics ,Lithium-ion battery ,Anode ,Ferrosilicon ,chemistry ,Chemical engineering ,General Materials Science ,Layer (electronics) - Abstract
Silicon, one of the most promising candidates as lithium-ion battery anode, has attracted much attention due to its high theoretical capacity, abundant existence, and mature infrastructure. Recently, Si nanostructures-based lithium-ion battery anode, with sophisticated structure designs and process development, has made significant progress. However, low cost and scalable processes to produce these Si nanostructures remained as a challenge, which limits the widespread applications. Herein, we demonstrate that Si nanoparticles with controlled size can be massively produced directly from low grade Si sources through a scalable high energy mechanical milling process. In addition, we systematically studied Si nanoparticles produced from two major low grade Si sources, metallurgical silicon (∼99 wt % Si, $1/kg) and ferrosilicon (∼83 wt % Si, $0.6/kg). It is found that nanoparticles produced from ferrosilicon sources contain FeSi2, which can serve as a buffer layer to alleviate the mechanical fractures of volume expansion, whereas nanoparticles from metallurgical Si sources have higher capacity and better kinetic properties because of higher purity and better electronic transport properties. Ferrosilicon nanoparticles and metallurgical Si nanoparticles demonstrate over 100 stable deep cycling after carbon coating with the reversible capacities of 1360 mAh g(-1) and 1205 mAh g(-1), respectively. Therefore, our approach provides a new strategy for cost-effective, energy-efficient, large scale synthesis of functional Si electrode materials.
- Published
- 2015
26. High-yield seedless synthesis of triangular gold nanoplates through oxidative etching
- Author
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Fei Ji, Qiao Zhang, Lei Chen, Yong Xu, Xiaohong Zhang, Feng Bao, Yifan Mi, Liu He, and Baoquan Sun
- Subjects
chemistry.chemical_classification ,Materials science ,Nanostructure ,Mechanical Engineering ,fungi ,Iodide ,Bioengineering ,Nanotechnology ,General Chemistry ,engineering.material ,Condensed Matter Physics ,Ion ,chemistry ,Chemical engineering ,Impurity ,Etching (microfabrication) ,Yield (chemistry) ,engineering ,General Materials Science ,Noble metal ,Surface plasmon resonance - Abstract
We demonstrate that monodispersed triangular gold nanoplates with high morphological yield (>90%) can be synthesized through a rapid one-pot seedless growth process. The edge length of triangular Au nanoplates can be readily tuned between 40 and 120 nm by varying the reaction parameters. Systematic studies reveal that distinct from previous hypothesis that the formation of nanoplates is mainly determined by the selective binding of iodide ions, our results show that iodide ions could have dual functions: it can selectively bind to the Au {111} facets and also selectively remove other less stable shape impurities through oxidative etching by forming tri-iodide ions (I(3)(-)), thus facilitating the formation of nuclei with dominant planar structure. This new synthetic route will not only help to better understand the growth mechanism of triangular gold nanoplates but also promote the research in anisotropic noble metal nanostructures.
- Published
- 2014
27. Photonic labyrinths: two-dimensional dynamic magnetic assembly and in situ solidification
- Author
-
Yadong Yin, Yu Lu, Qiao Zhang, Yongxing Hu, Michael Janner, Mingsheng Wang, and Le He
- Subjects
In situ ,Photons ,Fabrication ,Materials science ,business.industry ,Mechanical Engineering ,Bioengineering ,Nanotechnology ,General Chemistry ,Condensed Matter Physics ,Silicon Dioxide ,Ferric Compounds ,Nanostructures ,Magnetic Fields ,General Materials Science ,Colloids ,Photonics ,business ,Photonic crystal ,Sol-gel - Abstract
Creating novel structures by self-assembly processes and fixing the resultant assemblies are both critical to the design and fabrication of functional materials through bottom-up approaches. We demonstrate magnetically induced self-assembly of 2D photonic labyrinth structures and their solidification through a sol–gel method. The photonic labyrinth structures can be patterned into more regular arrangements using nonmagnetic substrates. This work may provide a platform for fabricating novel materials and devices with complex morphologies and spatial configurations.
- Published
- 2013
28. Magnetic assembly and patterning of general nanoscale materials through nonmagnetic templates
- Author
-
Le He, Yu Lu, Yadong Yin, Qiao Zhang, and Mingsheng Wang
- Subjects
chemistry.chemical_classification ,Ferrofluid ,Materials science ,Mechanical Engineering ,Bioengineering ,Nanotechnology ,General Chemistry ,Polymer ,Condensed Matter Physics ,Magnetic field ,law.invention ,Template ,chemistry ,law ,High spatial resolution ,General Materials Science ,Photolithography ,Nanoscopic scale ,Microfabrication - Abstract
Applied magnetic field represents an effective tool to rapidly assemble micro- and nanoscale magnetic objects into defined structures. Ordered assembly is typically achieved by using magnetic micropatterns, for which the downside is that they require advanced microfabrication techniques to produce. In addition, most conventional magnetic assembly strategies are restricted to target objects that possess magnetic properties. Herein we present a general strategy that allows convenient magnetically driven assembly of nonmagnetic objects in defined locations with high spatial resolution. The process involves immersing a polymer relief pattern in a uniformly magnetized ferrofluid, which modulates the local magnetic fields around the pattern. Nonmagnetic target objects dispersed in the same ferrofluid can then be magnetically assembled at positions defined by the polymer pattern. As the nonmagnetic polymer patterns can be conveniently fabricated at low cost through photolithography and soft-lithography processes, our method provides a general yet very effective means to assemble a wide range of nonmagnetic objects with controlled spatial distribution, paving the way toward patterning functional microstructures.
- Published
- 2012
29. Direct assembly of hydrophobic nanoparticles to multifunctional structures
- Author
-
Zhenda Lu, Chuanbo Gao, Qiao Zhang, Miaofang Chi, Jane Y. Howe, and Yadong Yin
- Subjects
Materials science ,Nanostructure ,Mechanical Engineering ,Composite number ,Nanoparticle ,Bioengineering ,Nanotechnology ,General Chemistry ,engineering.material ,Condensed Matter Physics ,Coating ,engineering ,Surface modification ,General Materials Science ,Self-assembly ,Luminescence ,Layer (electronics) - Abstract
We present a general process that allows convenient production of multifunctional composite particles by direct self-assembly of hydrophobic nanoparticles on host nanostructures containing high-density surface thiol groups. Hydrophobic nanoparticles of various compositions and combinations can be directly assembled onto the host surface through the strong coordination interactions between metal cations and thiol groups. The resulting structures can be further conveniently overcoated with a layer of normal silica to stabilize the assemblies and render them highly dispersible in water for biomedical applications. As the entire fabrication process does not involve complicated surface modification procedures, the hydrophobic ligands on the nanoparticles are not disturbed significantly so that they retain their original properties such as highly efficient luminescence. Many complex composite nanostructures with tailored functions can be efficiently produced by using this versatile approach. For example, multifunctional nonspherical nanostructures can be efficiently produced by using mercapto-silica coated nano-objects of arbitrary shapes as hosts for immobilizing functional nanoparticles. Multilayer structures can also be achieved by repeating the mercapto-silica coating and nanoparticle immobilization processes. Such assembly approach will provide the research community a highly versatile, configurable, scalable, and reproducible process for the preparation of various multifunctional structures.
- Published
- 2011
30. Seeded growth of uniform Ag nanoplates with high aspect ratio and widely tunable surface plasmon bands
- Author
-
Shirui Guo, Yadong Yin, James Goebl, Yongxing Hu, and Qiao Zhang
- Subjects
Range (particle radiation) ,Materials science ,Ligand ,Mechanical Engineering ,Surface plasmon ,Bioengineering ,Nanotechnology ,General Chemistry ,Adhesion ,Condensed Matter Physics ,Reaction rate ,Pulmonary surfactant ,General Materials Science ,Seeding ,Surface plasmon resonance - Abstract
Silver nanoplates with an extremely high aspect ratio (up to over 400) and a widely tunable surface plasmon resonance (SPR) band have been successfully synthesized by combining the concepts of selective ligand adhesion and seeded growth. Citrate ligands are used as the sole surfactant to effectively block overgrowth on the basal {111} facets and only allow growth in the lateral direction. By slowing down the reaction rate using Ag-citrate complex as precursor, the thin nature of Ag nanoplates is maintained with the edge length grown up to 4 μm, which ensures the high aspect ratio and the widely tunable SPR band. We also observe a size distribution focusing effect that helps to produce uniform nanoplates as well as narrow SPR bands over a wide range, which is important in many practical applications.
- Published
- 2010
31. From Nonluminescent Cs4PbX6 (X = Cl, Br, I) Nanocrystals to Highly Luminescent CsPbX3 Nanocrystals: Water-Triggered Transformation through a CsX-Stripping Mechanism.
- Author
-
Linzhong Wu, Huicheng Hu, Yong Xu, Shu Jiang, Min Chen, Qixuan Zhong, Di Yang, Qipeng Liu, Yun Zhao, Baoquan Sun, Qiao Zhang, and Yadong Yin
- Published
- 2017
- Full Text
- View/download PDF
32. Polymorphic Assembly from Beveled Gold Triangular Nanoprisms.
- Author
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Juyeong Kim, Xiaohui Song, Fei Ji, Binbin Luo, Ice, Nicole F., Qipeng Liu, Qiao Zhang, and Qian Chen
- Published
- 2017
- Full Text
- View/download PDF
33. The Synergy between Metal Facet and Oxide Support Facet for Enhanced Catalytic Performance: The Case of Pd-TiO2.
- Author
-
Muhan Cao, Zeyuan Tang, Qipeng Liu, Yong Xu, Min Chen, Haiping Lin, Youyong Li, Gross, Elad, and Qiao Zhang
- Published
- 2016
- Full Text
- View/download PDF
34. Hydrogenation Driven Conductive Na2Ti3O7 Nanoarrays as Robust Binder-Free Anodes for Sodium-Ion Batteries.
- Author
-
Shidong Fu, Jiangfeng Ni, Yong Xu, Qiao Zhang, and Liang Li
- Published
- 2016
- Full Text
- View/download PDF
35. Encapsulated Silver Nanoparticles Can Be Directly Converted to Silver Nanoshell in the Gas Phase.
- Author
-
Peipei Yang, Yong Xu, Lei Chen, Xuchun Wang, Baohua Mao, Zhongzhi Xie, Sui-Dong Wang, Feng Bao, and Qiao Zhang
- Published
- 2015
- Full Text
- View/download PDF
36. Scalable Production of Si Nanoparticles Directly fromLow Grade Sources for Lithium-Ion Battery Anode.
- Author
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Bin Zhu, Yan Jin, Yingling Tan, Linqi Zong, Yue Hu, Lei Chen, Yanbin Chen, Qiao Zhang, and Jia Zhu
- Published
- 2015
- Full Text
- View/download PDF
37. Seeded Growth of Uniform Ag Nanoplates with High Aspect Ratio and Widely Tunable Surface Plasmon Bands.
- Author
-
Qiao Zhang, Yongxing Hu, Shirui Guo, James Goebl, and Yadong Yin
- Subjects
- *
INORGANIC synthesis , *SILVER , *SURFACE plasmon resonance , *CHEMICAL kinetics , *SURFACE active agents , *CITRATES , *ADHESION - Abstract
Silver nanoplates with an extremely high aspect ratio (up to over 400) and a widely tunable surface plasmon resonance (SPR) band have been successfully synthesized by combining the concepts of selective ligand adhesion and seeded growth. Citrate ligands are used as the sole surfactant to effectively block overgrowth on the basal {111} facets and only allow growth in the lateral direction. By slowing down the reaction rate using Agâcitrate complex as precursor, the thin nature of Ag nanoplates is maintained with the edge length grown up to 4 μm, which ensures the high aspect ratio and the widely tunable SPR band. We also observe a size distribution focusing effect that helps to produce uniform nanoplates as well as narrow SPR bands over a wide range, which is important in many practical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
38. The Synergy between Metal Facet and Oxide Support Facet for Enhanced Catalytic Performance: The Case of Pd-TiO2.
- Author
-
Muhan Cao, Zeyuan Tang, Qipeng Liu, Yong Xu, Min Chen, Haiping Lin, Youyong Li, Gross, Elad, and Qiao Zhang
- Subjects
- *
PALLADIUM , *TITANIUM oxides , *NANOSTRUCTURES , *CATALYTIC activity , *MATERIALS science - Abstract
The demand for catalyst with higher activity and higher selectivity is still a central issue in current material science community. On the basis of first-principles calculations, we demonstrate that the catalytic performance of the Pd-TiO2 hybrid nanostructures can be selectively promoted or depressed by choosing the suitable shaped Pd and TiO2 nanocrystals. To be more specific, the catalytic activities of Pd nanoparticles enclosed by (100) or (111) facets can be promoted more significantly when dosed on the TiO2(001) than on TiO2(101) under irradiation. Such theoretical prediction has then been further verified by the experimental observations in which the Pd(100)-TiO2(001) composites exhibit the highest catalytic performance toward the activation of oxygen among all the other shaped hybrid nanostructures. As a result, the selection of facets of support materials can provide an extra tuning parameter to control the catalytic activities of metal nanoparticles. This research opened up a new direction for designing and preparing catalysts with enhanced catalytic performance. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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