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Park J, Cho I, Jeon H, Lee Y, Zhang J, Lee D, Cho MK, Preston DJ, Shong B, Kim IS, Lee WK. Conversion of Layered WS 2 Crystals into Mixed-Domain Electrochemical Catalysts by Plasma-Assisted Surface Reconstruction. Adv Mater 2024:e2314031. [PMID: 38509794 DOI: 10.1002/adma.202314031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/11/2024] [Indexed: 03/22/2024]
Abstract
Electrocatalytic water splitting is crucial to generate clean hydrogen fuel, but implementation at an industrial scale remains limited due to dependence on expensive platinum (Pt)-based electrocatalysts. Here, an all-dry process to transform electrochemically inert bulk WS2 into a multidomain electrochemical catalyst that enables scalable and cost-effective implementation of the hydrogen evolution reaction (HER) in water electrolysis is reported. Direct dry transfer of WS2 flakes to a gold thin film deposited on a silicon substrate provides a general platform to produce the working electrodes for HER with tunable charge transfer resistance. By treating the mechanically exfoliated WS2 with sequential Ar-O2 plasma, mixed domains of WS2, WO3, and tungsten oxysulfide form on the surfaces of the flakes, which gives rise to a superior HER with much greater long-term stability and steady-state activity compared to Pt. Using density functional theory, ultraefficient atomic sites formed on the constituent nanodomains are identified, and the quantification of atomic-scale reactivities and resulting HER activities fully support the experimental observations.
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Affiliation(s)
- Jiheon Park
- Department of Materials Science and Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - Iaan Cho
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - Hotae Jeon
- Department of Materials Science and Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - Youjin Lee
- Department of Materials Science and Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - Jian Zhang
- International Research Center for EM Metamaterials and Institute of Advanced Magnetic Materials, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018, China
| | - Dongwook Lee
- Department of Materials Science and Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - Min Kyung Cho
- Advanced Analysis and Data Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Daniel J Preston
- Department of Mechanical Engineering, Rice University, Houston, TX, 77005, USA
| | - Bonggeun Shong
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - In Soo Kim
- Nanophotonics Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- KIST-SKKU Carbon-Neutral Research Center, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Won-Kyu Lee
- Department of Materials Science and Engineering, Hongik University, Seoul, 04066, Republic of Korea
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Chen X, van Huis MA. Formation Pathways of Lath-Shaped WO 3 Nanosheets and Elemental W Nanoparticles from Heating of WO 3 Nanocrystals Studied via In Situ TEM. Materials (Basel) 2023; 16:1291. [PMID: 36770297 PMCID: PMC9920553 DOI: 10.3390/ma16031291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 01/28/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
WO3 is a versatile material occurring in many polymorphs, and is used in nanostructured form in many applications, including photocatalysis, gas sensing, and energy storage. We investigated the thermal evolution of cubic-phase nanocrystals with a size range of 5-25 nm by means of in situ heating in the transmission electron microscope (TEM), and found distinct pathways for the formation of either 2D WO3 nanosheets or elemental W nanoparticles, depending on the initial concentration of deposited WO3 nanoparticles. These pristine particles were stable up to 600 °C, after which coalescence and fusion of the nanocrystals were observed. Typically, the nanocrystals transformed into faceted nanocrystals of elemental body-centered-cubic W after annealing to 900 °C. However, in areas where the concentration of dropcast WO3 nanoparticles was high, at a temperature of 900 °C, considerably larger lath-shaped nanosheets (extending for hundreds of nanometers in length and up to 100 nm in width) were formed that are concluded to be in monoclinic WO3 or WO2.7 phases. These lath-shaped 2D particles, which often curled up from their sides into folded 2D nanosheets, are most likely formed from the smaller nanoparticles through a solid-vapor-solid growth mechanism. The findings of the in situ experiments were confirmed by ex situ experiments performed in a high-vacuum chamber.
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Affiliation(s)
- Xiaodan Chen
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
- Electron Microscopy Center, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Marijn A. van Huis
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
- Electron Microscopy Center, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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Dong Z, Zhang N, Wang S, Liu Y, Zhang L, Chen X, Luo L. In Situ Structural Dynamics of Atomic Defects in Tungsten Oxide. J Phys Chem Lett 2022; 13:7170-7176. [PMID: 35904340 DOI: 10.1021/acs.jpclett.2c01942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Atomic defects are critical to tuning the physical and chemical properties of functional materials such as catalysts, semiconductors, and 2D materials. However, direct structural characterization of atomic defects, especially their formation and annihilation under practical conditions, is challenging yet crucial to understanding the underlying mechanisms driving defect dynamics, which remain mostly elusive. Here, through in situ atomic imaging by an aberration-corrected environmental transmission electron microscope (AC-ETEM), we directly visualize the formation and annihilation mechanism of planar defects in monoclinic WO3 on the atomic scale in real time. We captured the atomistic process of the nucleation dynamics of the dislocation core in the [010] direction, followed by its propagation to form a planar defect. Corroborated by density functional theory-based calculations, we rationalize the formation of dislocation through O extraction from bridge sites followed by an atomic channeling process. These in situ observations shed light on the defect dynamics in oxides and provide atomic insights into forming and manipulating defects in functional materials.
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Affiliation(s)
- Zejian Dong
- Institute of Molecular Plus, Department of Chemistry, Tianjin University, Tianjin 300072, P. R. China
| | - Na Zhang
- Institute of Molecular Plus, Department of Chemistry, Tianjin University, Tianjin 300072, P. R. China
| | - Shuangbao Wang
- Key Laboratory of LCR Materials and Devices of Yunnan Province, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650091, P. R. China
| | - Yuying Liu
- School of Physical Science and Technology, Guangxi University, Nanning 530004, P. R. China
| | - Lifeng Zhang
- Institute of Molecular Plus, Department of Chemistry, Tianjin University, Tianjin 300072, P. R. China
| | - Xing Chen
- Institute of Molecular Plus, Department of Chemistry, Tianjin University, Tianjin 300072, P. R. China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, P. R. China
| | - Langli Luo
- Institute of Molecular Plus, Department of Chemistry, Tianjin University, Tianjin 300072, P. R. China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, P. R. China
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Cui Y, Wang Q, Yang G, Gao Y. Electronic properties, optical properties and diffusion behavior of WO3 with H+, Li+ and Na+ intercalated ions: A first-principles study. J SOLID STATE CHEM 2021. [DOI: 10.1016/j.jssc.2021.122082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Thwala MM, Dlamini LN. Photocatalytic reduction of Cr(VI) using Mg-doped WO 3 nanoparticles. Environ Technol 2020; 41:2277-2292. [PMID: 31181985 DOI: 10.1080/09593330.2019.1629635] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/05/2019] [Indexed: 06/09/2023]
Abstract
The hydrothermal synthesis method was employed for the fabrication of pristine tungsten trioxide (WO3) and that of varying dopant percentages (1, 3 and 5% m/m) of magnesium (Mg-WO3). The optical and structural properties of the synthesized materials were characterized using DRS, XRD, FTIR, TEM, BET, FESEM, XPS, PL, and Raman. Rectangular shaped nanostructures were observed through FESEM, wherein confirmed as monoclinic with the aid of XRD, FTIR and Raman analysis. Visualization of the doping was carried out using HRTEM imagery, which was also confirmed by a slight increase (0.0069 nm) of d spacing. As a consequence, band gaps were diminished and band edge positions were shifted. Band edge position shifts were confirmed via XPS analysis (0.08 eV). The point of zero charge was observed to shift towards positive upon doping at working pH 1 and 3.75 pH was the highest recorded. The rate of recombination was greatly reduced upon doping was observed through PL analysis. This was supported by DFT calculations, in which case the reduction of the rate of recombination was attributed to the introduction of Mg orbital. An improved efficiency was observed via the photo reduction of Cr(VI) metal ion in waste water, in which case, 97% reduction was attained.
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Affiliation(s)
- M M Thwala
- Department of Applied Chemistry, University of Johannesburg, Johannesburg, South Africa
| | - L N Dlamini
- Department of Applied Chemistry, University of Johannesburg, Johannesburg, South Africa
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García-garcía FJ, Mosa J, González-elipe AR, Aparicio M. Sodium ion storage performance of magnetron sputtered WO3 thin films. Electrochim Acta 2019; 321:134669. [DOI: 10.1016/j.electacta.2019.134669] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Li K, Shao Y, Yan H, Lu Z, Griffith KJ, Yan J, Wang G, Fan H, Lu J, Huang W, Bao B, Liu X, Hou C, Zhang Q, Li Y, Yu J, Wang H. Lattice-contraction triggered synchronous electrochromic actuator. Nat Commun 2018; 9:4798. [PMID: 30442958 DOI: 10.1038/s41467-018-07241-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 10/19/2018] [Indexed: 11/08/2022] Open
Abstract
Materials with synchronous capabilities of color change and actuation have prospects for application in biomimetic dual-stealth camouflage and artificial intelligence. However, color/shape dual-responsive devices involve stimuli that are difficult to control such as gas, light or magnetism, and the devices show poor coordination. Here, a flexible composite film with electrochromic/actuating (238° bending angle) dual-responsive phenomena, excellent reversibility, high synchronization, and fast response speed (< 5 s) utilizes a single active component, W18O49 nanowires. From in situ synchrotron X-ray diffraction, first principles calculations/numerical simulations, and a series of control experiments, the actuating mechanism for macroscopic deformation is elucidated as pseudocapacitance-based reversible lattice contraction/recovery of W18O49 nanowires (i.e. nanostructure change at the atomic level) during lithium ion intercalation/de-intercalation. In addition, we demonstrate the W18O49 nanowires in a solid-state ionic polymer-metal composite actuator that operates stably in air with a significant pseudocapacitive actuation. Materials that exhibit synchronous color change and actuation may benefit biomimetic camouflage, but stimuli can be difficult to control. Here the authors report a composite with electricity-driven electrochromic and actuating capabilities for use in a solid-state ionic polymer-metal composite actuator.
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Mandal D, Routh P, Nandi AK. A New Facile Synthesis of Tungsten Oxide from Tungsten Disulfide: Structure Dependent Supercapacitor and Negative Differential Resistance Properties. Small 2018; 14:1702881. [PMID: 29194967 DOI: 10.1002/smll.201702881] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/26/2017] [Indexed: 06/07/2023]
Abstract
Tungsten oxide (WO3 ) is an emerging 2D nanomaterial possessing unique physicochemical properties extending a wide spectrum of novel applications which are limited due to lack of efficient synthesis of high-quality WO3 . Here, a facile new synthetic method of forming WO3 from tungsten sulfide, WS2 is reported. Spectroscopic, microscopic, and X-ray studies indicate formation of flower like aggregated nanosized WO3 plates of highly crystalline cubic phase via intermediate orthorhombic tungstite, WO3. H2 O phase. The charge storage ability of WO3 is extremely high (508 F g-1 at current density of 1 A g-1 ) at negative potential range compared to tungstite (194 F g-1 at 1 A g-1 ). Moreover, high (97%) capacity retention after 1000 cycles and capacitive charge storage nature of WO3 electrode suggest its supremacy as a negative electrode of supercapacitors. The asymmetric supercapacitor, based on the WO3 as a negative electrode and mildly reduced graphene oxide as a positive electrode, manifests high energy density of 218.3 mWhm-2 at power density 1750 mWm-2 , and exceptionally high power density, 17 500 mW m-2 , with energy density of 121.5 mWh m-2 . Furthermore, the negative differential resistance (NDR) property of both WO3 and WO3 .H2 O are reported for the first time and NDR is explained with density of state approach.
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Affiliation(s)
- Debasish Mandal
- Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India
| | - Parimal Routh
- Department of Chemistry, Charuchandra College, 22 Lake Road, Kolkata, 700 029, India
| | - Arun K Nandi
- Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India
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Abstract
High levels of doping in WO3 have been experimentally observed to lead to structural transformation towards higher symmetry phases. We explore the structural phase diagram with charge doping through first-principles methods based on hybrid density functional theory, as a function of doping the room-temperature monoclinic phase transitions to the orthorhombic, tetragonal, and finally cubic phase. Based on a decomposition of energies into electronic and strain contributions, we attribute the transformation to a gain in energy resulting from a lowering of the conduction band on an absolute energy scale.
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Affiliation(s)
- Wennie Wang
- Materials Department, University of California, Santa Barbara, California 93106-5050, USA
| | - Anderson Janotti
- Materials Department, University of California, Santa Barbara, California 93106-5050, USA
| | - Chris G Van de Walle
- Materials Department, University of California, Santa Barbara, California 93106-5050, USA
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