13 results on '"Yong Wang"'
Search Results
2. Electron penetration triggering interface activity of Pt-graphene for CO oxidation at room temperature
- Author
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Xinhe Bao, Yanping Zheng, Ye Wang, Yunchuan Tu, Liang Yu, Chao Ma, Dehui Deng, Jingting Hu, Zhongmiao Gong, Wujun Zhang, Yong Wang, Fan Yang, Mingshu Chen, Pengju Ren, and Yi Cui
- Subjects
inorganic chemicals ,Materials science ,Science ,Alloy ,Oxide ,General Physics and Astronomy ,Nanoparticle ,engineering.material ,Heterogeneous catalysis ,General Biochemistry, Genetics and Molecular Biology ,Article ,law.invention ,Catalysis ,chemistry.chemical_compound ,Adsorption ,Transition metal ,law ,Multidisciplinary ,Graphene ,General Chemistry ,Chemical engineering ,chemistry ,engineering ,Nanoparticles - Abstract
Achieving CO oxidation at room temperature is significant for gas purification but still challenging nowadays. Pt promoted by 3d transition metals (TMs) is a promising candidate for this reaction, but TMs are prone to be deeply oxidized in an oxygen-rich atmosphere, leading to low activity. Herein we report a unique structure design of graphene-isolated Pt from CoNi nanoparticles (PtǀCoNi) for efficiently catalytic CO oxidation in an oxygen-rich atmosphere. CoNi alloy is protected by ultrathin graphene shell from oxidation and therefore modulates the electronic property of Pt-graphene interface via electron penetration effect. This catalyst can achieve near 100% CO conversion at room temperature, while there are limited conversions over Pt/C and Pt/CoNiOx catalysts. Experiments and theoretical calculations indicate that CO will saturate Pt sites, but O2 can adsorb at the Pt-graphene interface without competing with CO, which facilitate the O2 activation and the subsequent surface reaction. This graphene-isolated system is distinct from the classical metal-metal oxide interface for catalysis, and it provides a new thought for the design of heterogeneous catalysts., Achieving CO oxidation at room temperature is significant for gas purification but remains challenging to perform. Here, the authors report design of graphene-isolated Pt from cobalt-nickel nanoparticles for efficiently catalytic CO oxidation in an oxygen-rich atmosphere.
- Published
- 2021
3. Modulating Self-Assembly of DNA Crystals with Rationally Designed Agents
- Author
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Jiemin Zhao, Yue Zhao, Chengde Mao, Nadrian C. Seeman, Yong Wang, Zhe Li, and Ruojie Sha
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Models, Molecular ,Materials science ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,law.invention ,Crystallization kinetics ,chemistry.chemical_compound ,Dna nanostructures ,law ,DNA nanotechnology ,Crystallization ,Base Sequence ,010405 organic chemistry ,General Chemistry ,DNA ,General Medicine ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Nanoparticles ,Nucleic Acid Conformation ,Slow Growth Rate ,Self-assembly ,0210 nano-technology - Abstract
This manuscript reports a strategy for controlling the crystallization kinetics and improving the quality of engineered self-assembled 3D DNA crystals. Growing large, high-quality biomacromolecule crystals is critically important for determining the 3D structures of biomacromolecules. It often presents a great challenge to structural biologists. Herein, we introduce a rationally designed agent to modulate the crystallization process. Under such conditions, fewer, but larger, crystals that yield diffraction patterns of modestly higher resolution are produced compared with the crystals from conditions without the modulating agent. We attribute the improvement to a smaller number of nuclei and slow growth rate of crystallization. This strategy is expected to be generally applicable for crystallization of other biomacromolecules.
- Published
- 2018
4. Functionalizing Single Crystals: Incorporation of Nanoparticles Inside Gel-Grown Calcite Crystals
- Author
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Hongzheng Chen, Yong Wang, Xiaoqiang Chen, Wentao Yuan, Hanying Li, Yujing Liu, and Ye Shi
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Calcite ,Materials science ,Nanoparticle ,Hydrogels ,General Chemistry ,Crystal structure ,General Medicine ,Catalysis ,Calcium Carbonate ,law.invention ,Paramagnetism ,chemistry.chemical_compound ,Crystallography ,chemistry ,Chemical engineering ,Homogeneous ,law ,Nanoparticles ,Diamagnetism ,Agarose ,Crystallization - Abstract
Synthetic single crystals are usually homogeneous solids. Biogenic single crystals, however, can incorporate biomacromolecules and become inhomogeneous solids so that their properties are also extrinsically regulated by the incorporated materials. The discrepancy between the properties of synthetic and biogenic single crystals leads to the idea to modify the internal structure of synthetic crystals to achieve nonintrinsic properties by incorporation of foreign material. Intrinsically colorless and diamagnetic calcite single crystals are turned into colored and paramagnetic solids, through incorporation of Au and Fe3O4 nanoparticles without significantly disrupting the crystalline lattice of calcite. The crystals incorporate the nanoparticles and gel fibers when grown in agarose gel media containing the nanoparticles, whereas the solution-grown crystals do not. As such, our work extends the long-history gel method for crystallization into a platform to functionalize single-crystalline materials.
- Published
- 2014
5. Synthesis of nano titania particles embedded in mesoporous SBA-15: Characterization and photocatalytic activity
- Author
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Jun Zhang, Yu Tang, Yong-Wang Li, Yuanming Zhang, Yulei Zhu, Jun Yang, Liwei Zhu, and Shaoyuan Chen
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Titanium ,Anatase ,Environmental Engineering ,Materials science ,Light ,Health, Toxicology and Mutagenesis ,Mineralogy ,Mesoporous silica ,Silicon Dioxide ,Pollution ,Catalysis ,law.invention ,Adsorption ,Chemical engineering ,law ,Photocatalysis ,Nanoparticles ,Nanotechnology ,Environmental Chemistry ,Calcination ,Fourier transform infrared spectroscopy ,Photodegradation ,Mesoporous material ,Waste Management and Disposal - Abstract
Supported nanocrystalline titanium dioxide (TiO2) has been prepared by a post-synthesis step via Ti-alkoxide hydrolysis through the use of mesoporous SBA-15 silica. TiO2/SBA-15 composites with various TiO2 loading have been prepared and characterized by X-ray diffraction, nitrogen adsorption, Fourier transform infrared spectroscopy and diffusive reflective UV-vis spectroscopy. The addition of mesoporous SBA-15 prevents the anatase to rutile phase transformation and the growth of crystal grain. TiO2 did not block the SBA-15 pores, and their surface was fully accessible for nitrogen adsorption. Calcination in air of the composites up to 800 degrees C did not change the nanocrystal phase and slightly increased the domain size from 5.0 to 7.5 nm, indicating that the anatase TiO2 grains in the mesostructures have a relatively high thermal stability and proper pore diameter allows controlling the size of obtained titania particles. The TiO2/SBA-15 composites prepared by this study showed much higher photodegradation ability for methylene blue (MB) than commercial pure TiO2 nanoparticles P-25. Experimental results indicate that the photocatalytic activity of titania/silica mixed materials depends on the adsorption ability of composite and the photocatalytic activity of the titania, and there is an optimal ratio of Ti:Si, too high or low Ti:Si ratio will lower the photodegradation ability of the composites.
- Published
- 2006
6. Spectrophotometric analysis of phenols, which involves a hemin-graphene hybrid nanoparticles with peroxidase-like activity
- Author
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Serge Kokot, Yong Wang, Ruiling Sun, and Yongnian Ni
- Subjects
Environmental Engineering ,Health, Toxicology and Mutagenesis ,Catechols ,Wastewater ,Catalysis ,Nanocomposites ,chemistry.chemical_compound ,Spectrophotometry ,Partial least squares regression ,medicine ,Environmental Chemistry ,Organic chemistry ,Phenol ,Phenols ,Waste Management and Disposal ,medicine.diagnostic_test ,Hydroquinone ,Drinking Water ,Substrate (chemistry) ,Resorcinols ,Pollution ,Hydroquinones ,Lakes ,chemistry ,Peroxidases ,Principal component regression ,Hemin ,Nanoparticles ,Graphite ,Water Pollutants, Chemical ,Nuclear chemistry - Abstract
Phenols are well known noxious compounds, which are often found in various water sources. A novel analytical method has been researched and developed based on the properties of hemin-graphene hybrid nanosheets (H-GNs). These nanosheets were synthesized using a wet-chemical method, and they have peroxidase-like activity. Also, in the presence of H2O2, the nanosheets are efficient catalysts for the oxidation of the substrate, 4-aminoantipine (4-AP), and the phenols. The products of such an oxidation reaction are the colored quinone-imines (benzodiazepines). Importantly, these products enabled the differentiation of the three common phenols - pyrocatechol, resorcin and hydroquinone, with the use of a novel, spectroscopic method, which was developed for the simultaneous determination of the above three analytes. This spectroscopic method produced linear calibrations for the pyrocatechol (0.4-4.0 mg L(-1)), resorcin (0.2-2.0 mg L(-1)) and hydroquinone (0.8-8.0 mg L(-1)) analytes. In addition, kinetic and spectral data, obtained from the formation of the colored benzodiazepines, were used to establish multi-variate calibrations for the prediction of the three phenol analytes found in various kinds of water; partial least squares (PLS), principal component regression (PCR) and artificial neural network (ANN) models were used and the PLS model performed best.
- Published
- 2013
7. Surface facet of palladium nanocrystals: a key parameter to the activation of molecular oxygen for organic catalysis and cancer treatment
- Author
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Yao Fu, Ran Long, Xi-Sheng Wang, Wensheng Yan, Keke Mao, Xiaodong Ye, Yaobing Huang, Xiaojun Wu, Yi Xie, Jian-Yong Wang, and Yujie Xiong
- Subjects
Surface Properties ,chemistry.chemical_element ,General Chemistry ,engineering.material ,Photochemistry ,Biochemistry ,Catalysis ,Oxygen ,Electron transfer ,Colloid and Surface Chemistry ,chemistry ,Microscopy, Electron, Transmission ,Chemisorption ,Excited state ,Neoplasms ,engineering ,Molecule ,Humans ,Nanoparticles ,Noble metal ,Singlet state ,Palladium ,HeLa Cells - Abstract
In many organic reactions, the O(2) activation process involves a key step where inert ground triplet O(2) is excited to produce highly reactive singlet O(2). It remains elusive what factor induces the change in the electron spin state of O(2) molecules, although it has been discovered that the presence of noble metal nanoparticles can promote the generation of singlet O(2). In this work, we first demonstrate that surface facet is a key parameter to modulate the O(2) activation process on metal nanocrystals, by employing single-facet Pd nanocrystals as a model system. The experimental measurements clearly show that singlet O(2) is preferentially formed on {100} facets. The simulations further elucidate that the chemisorption of O(2) to the {100} facets can induce a spin-flip process in the O(2) molecules, which is achieved via electron transfer from Pd surface to O(2). With the capability of tuning O(2) activation, we have been able to further implement the {100}-faceted nanocubes in glucose oxidation. It is anticipated that this study will open a door to designing noble metal nanocatalysts for O(2) activation and organic oxidation. Another perspective of this work would be the controllability in tailoring the cancer treatment materials for high (1)O(2) production efficiency, based on the facet control of metal nanocrystals. In the cases of both organic oxidation and cancer treatment, it has been exclusively proven that the efficiency of producing singlet O(2) holds the key to the performance of Pd nanocrystals in the applications.
- Published
- 2013
8. Unique size-dependent nanocatalysis revealed at the single atomically precise gold cluster level.
- Author
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Yuwei Zhang, Ping Song, Tiankai Chen, Xiaodong Liu, Tao Chen, Zhemin Wu, Yong Wang, Jianping Xie, and Weilin Xu
- Subjects
CATALYSIS ,GOLD clusters ,NANOPARTICLES ,DISSOCIATION (Chemistry) ,QUANTUM chemistry ,ELECTRONIC structure ,FLUORESCENCE microscopy - Abstract
Atomically precise metal clusters have attracted increasing interest owing to their unique size-dependent properties; however, little has been known about the effect of size on the catalytic properties of metal clusters at the single-cluster level. Here, by real-time monitoring with single-molecule fluorescence microscopy the size-dependent catalytic process of individual Au clusters at single-turnover resolution, we study the size-dependent catalytic behaviors of gold (Au) clusters at the single-cluster level, and then observe the strong size effect on the catalytic properties of individual Au clusters, in both catalytic product formation and dissociation processes. Surprisingly, indicated by both experiments and density functional theory (DFT) calculations, due to such a unique size effect, besides observing the different product dissociation behaviors on different-sized Au clusters, we also observe that small Au clusters [i.e., Au
15 (MPA)13 ; here, MPA denotes 3-mercaptopropionic acid] catalyze the product formation through a competitive Langmuir-Hinshelwood mechanism, while those relatively larger Au clusters [e.g., Au18 (MPA)14 and Au25 (MPA)18 ] or nanoparticles catalyze the same process through a noncompetitive Langmuir-Hinshelwood mechanism. Such a size effect on the nanocatalysis could be attributed intrinsically to the size-dependent electronic structure of Au clusters. Further analysis of dynamic activity fluctuation of Au clusters reveals more different catalytic properties between Au clusters and traditional Au nanoparticles due to their different size-dependent structures. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
9. Highly selective hydrogenation of phenol and derivatives over a Pd@carbon nitride catalyst in aqueous media
- Author
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Jia Yao, Dang Sheng Su, Haoran Li, Markus Antonietti, and Yong Wang
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Surface Properties ,Cyclohexanone ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Phenols ,Nitriles ,Phenol ,Organic chemistry ,Particle Size ,Carbon nitride ,Aqueous medium ,Molecular Structure ,Chemistry ,Cyclohexanones ,Temperature ,Water ,General Chemistry ,021001 nanoscience & nanotechnology ,Highly selective ,0104 chemical sciences ,Pd nanoparticles ,Polyamide ,Nanoparticles ,Hydrogenation ,0210 nano-technology ,Porosity ,Palladium ,Hydrogen - Abstract
Cyclohexanone is an important intermediate in the manufacture of polyamides in chemical industry, but direct selective hydrogenation of phenol to cyclohexanone under mild conditions is a challenge. We report here a catalyst made of Pd nanoparticles supported on a mesoporous graphitic carbon nitride, Pd@mpg-C(3)N(4), which was shown to be highly active and promoted the selective formation of cyclohexanone under atmospheric pressure of hydrogen in aqueous media without additives. Conversion of 99% and a selectivity higher than 99% were achieved within 2 h at 65 °C. The reaction can be accelerated at higher temperature, but even at room temperature, 99% conversion and 96% selectivity could still be obtained. The generality of the Pd@mpg-C(3)N(4) catalyst for this reaction was demonstrated by selective hydrogenation of other hydroxylated aromatic compounds with similar performance.
- Published
- 2011
10. High-purity separation of gold nanoparticle dimers and trimers
- Author
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Hongyu Chen, Yong Wang, Lee Siew Tan, Gang Chen, Miaoxin Yang, Li Huey Tan, and Yuan Chen
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Polymers ,Dimer ,High resolution ,Nanoparticle ,Cesium ,Metal Nanoparticles ,Trimer ,Centrifugation ,Photochemistry ,Ligands ,Biochemistry ,Catalysis ,law.invention ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Chlorides ,Microscopy, Electron, Transmission ,law ,Nanotechnology ,Colloids ,Crystallization ,Chemistry ,General Chemistry ,Physical chemistry ,Nanoparticles ,Polystyrenes ,Gold ,Dimerization - Abstract
An effective method was developed for separating gold-nanoparticle clusters in high resolution; dimer and trimer samples were obtained with 95% and 81% purity, respectively.
- Published
- 2009
11. PREPARATION OF VANADIUM CATALYST CONTAINING NANO-V2O5 PARTICLES.
- Author
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Wei Wang, Jiacheng Gao, Yong Wang, and Jian Zhou
- Subjects
VANADIUM ,CATALYSTS ,NANOPARTICLES ,NANOSTRUCTURES ,CHEMICAL inhibitors ,CATALYSIS - Abstract
A new preparation process of the vanadium catalyst with nano-V
2 O5 particles was introduced in this paper. The inorganic sol-gel method is used to prepare the sols and gels with p nano-V2 O5 particles. The morphology, size and distribution of the nano-V2 O5 particles in the sols-gels and vanadium catalyst had been studied by TEM, SEM, XRD and DSC. The results show that with the w/v (the ratio of water and vanadium) declining, the morphology of the nano-V2 O5 particles varies from needle to near-ball then to sphere; the better process parameter to prepare the sols and gels with nano-V2 O5 particles is 800~860°C×10~15min; the sols and gels and catalyst with 30~60nm V2 O5 particles had been obtained by this process. [ABSTRACT FROM AUTHOR]- Published
- 2005
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12. Theoretical study about adsorbed oxygen reduction over χ-Fe5C2: formation of H2O and CO2.
- Author
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Bai, Ya, Liu, Jinjia, Wang, Tao, Song, Yu-Fei, Yang, Yong, Li, Yong-Wang, and Wen, Xiaodong
- Subjects
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OXYGEN reduction , *CHEMICAL reduction , *NANOPARTICLES , *CATALYSIS , *PHYSICAL & theoretical chemistry - Abstract
• The mechanism for eliminating adsorbed oxygen by the reduction with H and CO on χ-Fe 5 C 2 surfaces was investigated. • The removal mechanism shows diversity over different facets. • Carbon-rich surface exhibits higher barriers to direct CO 2 formation, like (110) and (111). The removal of surface oxygen adsorbed on iron carbides is essential to protect the nanoparticle from oxidation in heterogeneous catalysis. Herein, we explored the removal of pre-adsorbed oxygen on seven facets of χ-Fe 5 C 2, and four pathways including both direct and indirect routes for generating H 2 O and CO 2 were investigated. The removal mechanism shows diversity over different facets. On (010), the formation of CO 2 through the reaction between surface oxygen and adsorbed CO is more favorable. While on (510), (001), (110), (11-1) and (-411), the elimination in the form of H 2 O through OH disproportionation dominates. In particular, surface oxygen can be removed facilely either in H 2 O or CO 2 on (111) surface. What's more, surface with more carbons exhibits higher barriers to direct CO 2 formation, like (110) and (111). Our work provides knowledge about mechanism of O removal and CO 2 formation, which may be helpful in protecting the nanoparticle from further oxidation. Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
13. Characterization of Dispersed Heteropoly Acid on Mesoporous Zeolite Using Solid-State 31P NMR Spin-Lattice Relaxation.
- Author
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Kake Zhu, Jianzhi Hu, Xiaoyan She, Jun Liu, Zimin Nie, Yong Wang, Peden, Charles H. F., and Ja Hun Kwak
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HETEROCHAIN polymers , *CATALYSTS , *CATALYSIS , *CHEMICAL inhibitors , *ZEOLITE absorption & adsorption , *NANOPARTICLES - Abstract
Dispersion and quantitative characterization of supported catalysts is a grand challenge in catalytic science. In this paper, heteropoly acid H3PW12O40 (HPA) is dispersed on mesoporous zeolite silicalite-1 derived from hydrothermal synthesis using carbon black nanoparticle templates, and the catalytic activity is studied for 1-butene isomerization. The HPAs supported on conventional zeolite and on mesoporous zeolite exhibit very different activities and thus provide good model systems to investigate the structure dependence of the catalytic properties. The HPA on mesoporous silicalite-1 shows enhanced catalytic activity for 1 -butene isomerization, while HPA on conventional silicalite-1 exhibits low activity. To elucidate the structural difference, supported HPA catalysts are characterized using a variety of techniques, including 31P magic angle spinning nuclear magnetic resonance, and are shown to contain a range of species on both mesoporous and conventional zeolites. However, contrary to studies reported in the literature, conventional NMR techniques and chemical shifts alone do not provide sufficient information to distinguish the dispersed and aggregated surface species. The dispersed phase and the nondispersed phase can only be unambiguously and quantitatively characterized using spin-lattice relaxation NMR techniques. The HPA supported on mesoporous zeolite contains a fast relaxation component related to the dispersed catalyst, giving a much higher activity, while the HPA supported on conventional zeolite has essentially only the slow relaxation component with very low activity. The results obtained from this work demonstrate that the combination of spinning sideband fitting and spin-lattice relaxation techniques can provide detailed structural information on not only the Keggin structure for HPA but also the degree of dispersion on the support. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
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