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Search Publications by: Renu Sharma (Assoc)

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Displaying 1 - 25 of 51

Atomic Origin of the Autocatalytic Reduction of Monoclinic CuO in a Hydrogen Atmosphere

September 27, 2021
Author(s)
Xianhu Sun, Dongxiang Wu, Wenhui Zhu, Xiaobo Chen, Renu Sharma, Judith Yang, Guangwen Zhou
Reducibility is a prerequisite for the use of bulk metal oxides in chemical transformation 17 involving redox reactions but probing microscopic processes of oxide reduction is challenging as 18 the insulating nature of bulk oxides restricts ion and

Endothermic reaction at room temperature enabled by deep-ultraviolet plasmons

November 2, 2020
Author(s)
Canhui Wang, Wei-Chang Yang, David Raciti, Alina Bruma, Ronald Marx, Amit Agrawal, Renu Sharma
Sequestration and conversion of CO2 is a promising method for remedying climate change. However, current technologies remain limited due to infeasible system demands and outputs, such as high-temperature/pressure conditions, use of precious metals, or low

Towards data-driven next-generation transmission electron microscopy

October 26, 2020
Author(s)
Steven R. Spurgeon, Colin Ophus, Lewys Jones, Amanda K. Petford-Long, Sergei Kalinin, Matthew J. Olszta, Rafal Dunin-Borkowski, Norman Salmon, Khalid Hattar, Wei-Chang Yang, Renu Sharma, Yingge Du, Ann Chiaramonti Debay, Haimei Zheng, Edgar C. Buck, Libor Kovarik, R. Lee Penn, Dongsheng Li, Xin Zhang, Mitsuhiro Murayama, Mitra D. Taheri
The rapidly evolving field of electron microscopy touches nearly every aspect of modern life, underpinning impactful materials discoveries in applications such as quantum information science, energy, and medicine. As the field enters a new decade, a

A structure and activity relationship for single-walled carbon nanotube growth confirmed by in situ observations and modeling

October 5, 2020
Author(s)
Chao (. Hsin-Yun, Jiang Hua, Acevedo O. Francisco, Perla Balbuena, Esko Kauppinen, John Cumings, Renu Sharma
The structure and phase transformation of cobalt (Co) catalyst, during single walled carbon nanotube (SWCNT) growth, is elucidated for inactive, active and deactivated nanoparticles by in-situ imaging using an environmental transmission electron microscope

Modeling the Electromagnetic Scattering Characteristics of Carbon Nanotube Composites Characterized by 3D Tomographic Transmission Electron Microscopy

May 7, 2020
Author(s)
Ahmed M. Hassan, Md Khadimul Islam, Spencer On, Bharath Natarajan, Itai Stein, Noa Lachman, Estelle Cohen, Brian L. Wardle, Renu Sharma, James Alexander Liddle, Edward Garboczi
In nearly all prior modeling studies of the electromagnetic properties of carbon nanotube (CNT) composites, the three-dimensional (3D) shape and spatial distribution of the CNTs in the composite were unknown. Therefore, simplifying assumptions had to be

Surface-reaction induced structural oscillations in the subsurface

January 16, 2020
Author(s)
Xianhu Sun, Wenhui Zhu, Dongxiang WU, Chaoran Li, Jianyu Wang, Yaguang Zhu, Xiaobo Chen, Jorge A. Boscoboinik, Renu Sharma, Guangwen Zhou
Surface and subsurface are commonly considered as separate entities because of the difference in the bonding environment and are often investigated separately due to the experimental challenges in differentiating the surface and subsurface effects. Using

Can single-walled carbon nanotube diameter be defined by catalyst particle diameter?

December 2, 2019
Author(s)
Mauricio C. Diaz, Jiang Hua, Esko Kauppinen, Renu Sharma, Perla Balbuena
The need of designing and controlling single-walled carbon nanotube (SWCNT) properties is a challenge in a growing nanomaterials-related industry. Recently, great progress has been made experimentally to selectively control SWCNT diameter and chirality

Unveiling defect-mediated charge-carrier recombination at the nanometer scale in polycrystalline solar cells

November 20, 2019
Author(s)
Yohan Yoon, Wei-Chang Yang, Dongheon Ha, Paul M. Haney, Daniel Hirsch, Heayoung Yoon, Renu Sharma, Nikolai Zhitenev
In this work, we employ two techniques, near-field scanning photocurrent microscopy (NSPM) and transmission electron microscope based cathodoluminescence spectroscopy (TEM-CL), to analyze the nanoscale electrical and optical properties of CdTe solar cells

Atomic-scale mechanism of unidirectional oxide growth

November 14, 2019
Author(s)
Xianhu Sun, Wenhui Zhu, Dongxiang WU, Zhenyu Liu, Xiaobo Chen, Lu Yuan, Guofeng Wang, Renu Sharma, Guangwen Zhou
A fundamental knowledge of the unidirectional growth mechanisms is required for precise control on size, shape, and thereby functionalities of nanostructures. Using transmission electron microscopy that spatially and temporally resolves CuO nanowire growth

Low-temperature growth of carbon nanotubes catalyzed by sodium-based ingredients

May 27, 2019
Author(s)
Renu Sharma, Richard Li, Erica F. Antunes, Estekke Cohen, Akira Kudo, Luiz Acauan, Wei-Chang D. Yang, Chih-Ming Wang, Kehang Cui, Andrew Liotta, Ananth G. Rajan, Jules Gardner, David C. Bell, Michael S. Strano, James A. Liddle, Brian L. Wardle
Nanoparticle-catalytic synthesis of carbon nanostructures is an attractive route for producing 1-dimensional carbon nanomaterials, such as carbon nanotubes1 (CNTs), in large enough quantities for their multifunctional capabilities to be applied in

Metastable morphological states of catalytic nanoparticles

March 1, 2018
Author(s)
Pin A. Lin, Bharath N. Natarajan, Michael P. Zwolak, Renu Sharma
During the catalytic synthesis of graphene, nanotubes, fibers, and other nanostructures, many intriguing phenomena occur, such as phase separation, precipitation, and processes similar to capillary action. The underlying mechanism of these processes and

Direct evidence of atomic-scale structural fluctuations in catalyst nanoparticles

May 1, 2017
Author(s)
Pin Ann Lin, Jose Gomez-Ballesteros, Juan Burgos, Perla Balbuena, Bharath N. Natarajan, Renu Sharma
A heterogeneous catalyst usually works by letting the reactant adsorb onto its surface where the energies for specific bonds to dissociate and/or combine with other species (to form desired intermediate or final products) are lower. Rational catalyst

In situ Atomic-Scale Probing of Reduction Dynamics of 2-Dimensional Fe2O3 Nanostructures

December 13, 2016
Author(s)
Wenhui Zhu, Jonathan P. Winterstein, Wei-Chang Yang, Lu Yuan, Renu Sharma, Guangwen Zhou
Atomic-scale structure dynamics and phase transformation pathway was probed, in situ, during the reduction of bi-crystalline Fe2O3 nanostructures in H2 by using an environmental transmission electron microscope. It was found that the reduction commenced

Current status and future directions for in situ transmission electron microscopy

August 6, 2016
Author(s)
M. L. Taheri, Eric Stach, Ilke Arslan, Peter A. Crozier, Kabius Bernd, Thomas LaGrange, Andrew Minor, Seiji Takeda, Mihaela M. Tanase, Jakob B. Wagner, Renu Sharma
This review article discusses the current and future possibilities for the application of in situ transmission electron microscopy to reveal synthesis pathways and functional mechanisms in complex and nanoscale materials. The findings of a group of

Multiscale Metrologies for Process Optimization of Carbon Nanotube Polymer Composites

July 18, 2016
Author(s)
Bharath N. Natarajan, Nate Orloff, Rana N. Ashkar, Sagar Doshi, Kevin A. Twedt, Ajay Krishnamurthy, Chelsea S. Davis, Aaron M. Forster, Erik Thostenson, Jan Obrzut, Renu Sharma, James Alexander Liddle
Carbon nanotube (CNT) polymer composites are materials with attractive multifunctional properties that are becoming used in a growing range of commercial applications. With the increasing demand for these materials, it is imperative to develop methods for

Atomic structural evolution during the reduction of a-Fe2O3 nanowires

June 20, 2016
Author(s)
Wenhui Zhu, Jonathan P. Winterstein, Itai Maimon, Qiyue Yin, Lu Yuan, Aleksey N. Kolmogorov, Renu Sharma, Guangwen Zhou
The atomic-scale reduction mechanism of α-Fe2O3 nanowires by H2 was followed using transmission electron microscopy to reveal the evolution of atomic structures and the associated transformation pathways for different iron oxides. The reduction commences

Growth of one-dimensional nanomaterials in the ETEM

January 1, 2016
Author(s)
Jonathan P. Winterstein, Renu Sharma
One-dimensional nanomaterials (nanowires and nanotubes) have a number of unique and interesting properties that have made them the subject of significant research for a wide range of applications. Electron microscopy is generally necessary for their

Charge transfer stabilization of late transition metal oxide nano-particles on a layered niobate support

December 10, 2015
Author(s)
Megan E. Strayer, Thomas Senftle, Jonathan P. Winterstein, Nella M. Vargas-Barbosa, Renu Sharma, Robert M. Rioux, Michael J. Janik, Thomas Mallouk
The interfacial interactions between late transition metal/metal oxide nanoparticles and oxide supports impact catalysts' activity and stability. Here, we report the use of isothermal titration calorimetry (ITC), electron microscopy and density functional

High-Resolution Imaging and Spectroscopy at High Pressure: A Novel Liquid Cell for the Transmission Electron Microscope

December 9, 2015
Author(s)
Mihaela M. Tanase, Jonathan P. Winterstein, Renu Sharma, Vladimir A. Aksyuk, Glenn E. Holland, James A. Liddle
We demonstrate quantitative core-loss electron energy-loss spectroscopy of iron oxide nanoparticles and imaging resolution of Ag nanoparticles in liquid down to 0.24 nm, in both transmission and scanning-transmission modes, in a novel, monolithic liquid