Biosketch

Dr. Ni’s general research interest centers on the characterization of novel structures and composites utilizing transmission electron microscopy (TEM), scanning electron microscopy (SEM) and other cutting-edge equipment. Expertise includes electron crystallography and e-beam associated spectroscopy. Active efforts are on the process-structure-property relationships of advanced composites, mesoporous crystals, functionalized nanostructures and assemblies, thin films and interfaces.

Research Interests

IN-SITU & LOW-DOSE ELECTRON MICROSCOPY

Due to increasing needs for probing dynamic properties of multifunctional responsive materials or investigating polymeric/bio-materials of high electron-beam sensitivity, a broad range of ancillary equipment has been acquired and/or customized in the past few years for in-situ or low-dose electron microscopy. Specifically, electrochemical analysis, cryo-microscopy, and mechanical or mechanoelectrical testing in both TEM and SEM for nano- to micro-scale materials or structures are being explored. Active research focuses on the phase transformation, interactions, and assembling of materials and structures within a designed environment simulating applications for electronics, photonics, electrochemistry and biochemistry.

NANOSTRUCTURES FOR DESIRED FUNCTIONS AND ENVIRONMENTAL/ENERGY APPLICATIONS

Nanostructures and assemblies demonstrate unprecedented potentials for novel phenomena, properties and applications that were not accessible before. A major component of Dr. Ni’s research focuses on the fabrication and/or the characterization of designed novel nanostructures and assemblies. In one effort, Ag nano-crystals were grown via a method with structural characteristics as mediated by the surfactant molecules in an aqueous solution. Using transmission electron microscopy, this special nanorod was characterized and was found to be a truncated decahedral structure consisting of five crystal units packing along {111} twining planes with five {111} planes on each end and five circumferential {001} side surfaces parallel to a longitudinal direction so as to allow most active crystal planes exposed.

In another effort, by constructing active nanocomponents, in-situ TEM is used to probe and discover new phenomena for potential applications in advanced technologies.

PROCESS-STRUCTURE-PROPERTY OF MULTIFUNCTIONAL COMPOSITES

Multifunctional composites including polymer matrix composites (PMC), metal matrix composites (MMC) and ceramic matrix composites (CMC) remain to be one of the major research interests. Special interest centers on interfaces, reactive-diffusion, phase formation and local properties and functions that usually need to be resolved by electron microscopy and/or in-situ testing. Currently, on-going projects include diamond/SiC thin films and their properties including interfacial properties and interfacial transport behaviors.

PHARMACEUTICAL MATERIALS AND POLYMORPHISM

In the development of new medicines, desired properties of active pharmaceutical ingredients (API) are not only due to their chemicals but also very much dependent on the crystal structures. Understanding the crystal polymorphism is therefore essential for the screening of APIs and the efficacy of drugs. Low-dose imaging and nano-diffraction can play an essential role.

For example, a palladium catalyst supported by Si-thiol, a commercially available mercaptopropyl-modified and TMS-passivated amorphous silica, was synthesized and characterized by aberration-corrected STEM-HAADF and other cutting-edge equipment. Statistical analysis revealed that the catalytic Pd species can exist as a mixture of isolated atoms (ca. 0.1 nm) and atomic clusters (<2 nm) in addition to relatively larger nanoparticles (<5 nm). The nanoscale atomic clusters dominate the reactivity and serve as the key active sites for Suzuki coupling. The Pd/Si-thiol was demonstrated to be reusable for more than three times without a noticeable loss of catalytic activity.

Representative Publications

1. Chun-yen Hsu, Yuying Zhang, Prashant Karandikar, Fei Deng, Chaoying Ni, Mechanical Properties of α-SiC and Correlation to SiC/Si Interface at Nanoscale from Reaction Bonded SiC/Si Composites (RBSC), Applied Composite Materials, 27, 2020, 433-445, https://doi.org/10.1007/s10443-020-09825-3

2. Xiazhang Li, Hui-Yin H Li, David Charles Martin, Chaoying Ni, Si-thiol Supported Atomic-scale Palladium as Efficient and Recyclable Catalyst for Suzuki Coupling Reaction, Nanotechnology, 31, 2020, 355704, https://doi.org/10.1088/1361-6528/ab9473

3. Theresa P. Ginley, Yuying Zhang, Chaoying Ni, and Stephanie Law, Epitaxial growth of Bi₂Se₃ in the (0015) Orientation on GaAs (001), Vac. Sci. Technol. A, 38(2), 023404.1-7 https://doi.org/10.1116/1.5139905

4. Xiazhang Li, Zhendong Wang, Haiyang Shi, Da Dai, Shixiang Zuo, Chao Yao, Chaoying Ni, Full spectrum driven SCR removal of NO over hierarchical CeVO₄/attapulgite nanocomposite with high resistance to SO₂ and H₂O, Journal of Hazardous Materials, 386, 2020, 121977 https://doi.org/10.1016/j.jhazmat.2019.121977

5. Qiong Xu, Aibin Ma, Yuhua Li, Jiapeng Sun, Yuchun Yuan, Jinghua Jiang, Chaoying Ni, Microstructure evolution of AZ91 alloy processed by a combination method of equal channel angular pressing and rolling, Journal of Magnesium and Alloys, 8(1), March 2020, 192-198 https://doi.org/10.1016/j.jma.2019.05.012

6. Qiong Xu, Aibin Ma, Bassiouny Saleh, Yuhua Li, Yuchun Yuan, Jinghua Jiang, Chaoying Ni, Enhancement of strength and ductility of SiCp/AZ91 composites by RD-ECAP processing, Materials Science and Engineering: A, 771, 2020, 138579 https://doi.org/10.1016/j.msea.2019.138579

7. Bo E. Tew, Yuying Zhang, Areej Shahid, Matthew R. Lewis, Chaoying Ni, Joshua M. O. Zide, Growth and Thermal Characterization of TbAs Nanoparticles Grown by Inert Gas Condensation, Journal of Electronic Materials, 2020, 1-6, http://doi.org/10.1007/s11664-019-07737-y

8. Xinxin Wang, Hongxia Yin, Yuxia Guan, Yuxiang Yang, Yan Huang, Hongming Yuan, Xiangnong Liu, Chaoying Ni, Graphene Oxide Covalently Grafted Fe₂B@ SiO₂ Nanoparticles for Epirubicin Loading and Releasing, Journal of nanoscience and nanotechnology, 20(4), 2020, 2104-2113(10), https://doi.org/10.1166/jnn.2020.17360

9. Carly Byron, Shi Bai, Gokhan Celik, Magali S. Ferrandon, Cong Liu, Chaoying Ni, Ali Mehdad, Massimiliano Delferro, Raul Lobo, and Andrew V. Teplyakov, Role of Boron in Enhancing the Catalytic Performance of Supported Platinum Catalysts for the Nonoxidative Dehydrogenation of n-Butane, ACS Catalysis, 2020, 10, 2, 1500-1510. https://doi.org/10.1021/acscatal.9b04689

10. Zhengxin Li, Meng Jia, Samantha Doble, Emily Hockey, Han Yan, Joseph Avenoso, Daniel Bodine, Yuying Zhang, Chaoying Ni, John T Newberg, Lars Gundlach, Energy Band Architecture of a Hierarchical ZnO/Au/Cu_xO Nanoforest by Mimicking Natural Superhydrophobic Surfaces, ACS Appl. Mater. Interfaces, 2019 https://doi.org/10.1021/acsami.9b13610

11. Changhao Liu, Isao Noda, D. Bruce Chase, Yuying Zhang, Jing Qu, Meng Jia, Chaoying Ni, John F. Rabolt, Crystallization Retardation of Ultrathin Films of Poly [(R)-3-hydroxybutyrate] and a Random Copolymer Poly [(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] on an Aluminum Oxide Surface, Macromolecules, 52(19), 2019, 7343-7352 https://doi.org/10.1021/acs.macromol.9b01214

12. Chun-yen Hsu, Yuying Zhang, Yunsong Xie, Fei Deng, Prashant Karandikar, John Q Xiao, Chaoying Ni, In-situ measurement of SiC/Si interfacial tensile strength of reaction bonded SiC/Si composite, Composites Part B: Engineering, 175, 2019, 107116 https://doi.org/10.1016/j.compositesb.2019.107116

13. Yuying Zhang, Chun-Yen Hsu, Prashant Karandikar, Chaoying Ni, Interfacial zone surrounding the diamond in reaction bonded diamond/SiC composites: interphase structure and formation mechanism, Journal of the European Ceramic Society, 39(16), 2019, 5190-5196. https://doi.org/10.1016/j.jeurceramsoc.2019.08.019

14. Yan Huang, Jie Li, Yuxiang Yang, Hongming Yuan, Qinmei Wei, Xiangnong Liu, Yi Zhao, Chaoying Ni, Characterization of enzyme-immobilized catalytic support and its exploitation for the degradation of methoxychlor in simulated polluted soils, Environmental Science and Pollution Research, 2019, 1-13 https://doi.org/10.1007/s11356-019-05937-x

15. Jie Zhang, Peng Cui, Guangyang Lin, Yuying Zhang, Maria Gabriela Sales, Meng Jia, Zhengxin Li, Christopher Goodwin, Thomas Beebe, Lars Gundlach, Chaoying Ni, Stephen McDonnell, Yuping Zeng, High performance anatase-TiO₂ thin film transistors with two-step oxidized TiO₂ channel and plasma enhanced atomic layer-deposited ZrO₂ gate dielectric, Applied Physics Express, 12(9), 2019, 096502, https://doi.org/10.7567/1882-0786/ab3690

16. Bo E. Tew, Matthew R. Lewis, Chun-Yen Hsu, Chaoying Ni, Joshua M.O. Zide, Growth of ErAs: GaAs nanocomposite by liquid phase epitaxy, Journal of Crystal Growth, 518, 2019, 34-38, https://doi.org/10.1016/j.jcrysgro.2019.04.025

17. Chun‐Yen Hsu, Kathryn Scrafford, Chaoying Ni, Fei Deng, Study of tensile properties of multiwalled carbon nanotube/polyether ether ketone polymer composites at the nanoscale, Polymer Engineering & Science, 59(6), 2019, 1209-1214 https://doi.org/10.1002/pen.25103

18. Juan Xu, Huada Cao, Chaoying Ni, Yan Wang, Jianyu Cao, Zhidong Chen, Design and synthesis of sandwich-like CoNi₂S₄@C@NiCo-LDH microspheres for supercapacitors, J Solid State Electrochem, (2019), 1-10 https://doi.org/10.1007/s10008-019-04246-0

19. Shawn P. Sullivan, Timothy R. Leftwich, Christopher M. Goodwin, Chaoying Ni, Andrew V. Teplyakov, Thomas P. Beebe, Growth and Chemical Modification of Silicon Nanostructures Templated in Molecule Corrals: Parallels with the Surface Chemistry of Single Crystalline Silicon, Surface Science, 683, 2019, 38-45 https://doi.org/10.1016/j.susc.2019.01.010

20. Xiazhang Li, Haiyang Shi, Xiangyu Yan, Shixiang Zuo, Yuying Zhang, Qun Chen, Chao Yao, Chaoying Ni, Rational construction of direct Z-scheme doped perovskite/palygorskite nanocatalyst for photo-SCR removal of NO: Insight into the effect of Ce incorporation, Journal of Catalysis, 369 (2019), 190-200, https://doi.org/10.1016/j.jcat.2018.11.009