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Premanand G, Jana D, Unnikrishnan PM, Das SK. Hexagonal Mo Bronze: Single Crystal Structures, Electrocatalytic Hydrogen Evolution, and Proton Conductivity. Inorg Chem 2024; 63:10671-10681. [PMID: 38805640 DOI: 10.1021/acs.inorgchem.4c01151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Molybdenum trioxide (MoO3) is a well-known transition metal oxide that has drawn much attention as a functional material having numerous applications. However, a vast majority of studies have primarily focused on α-MoO3, the thermodynamically stable polymorph of MoO3. This present work encompasses the synthesis of single crystals of two metastable hexagonal MoO3 described by the formulas {Mn0.03Na0.01}@[Mo0.93VIMo0.07VO3] (1) and {Cu0.01Na0.01}@[Mo0.97VIMo0.03VO3] (2), their comprehensive structural characterization by single-crystal X-ray crystallography, and routine spectral and microscopic studies. Interestingly, compound 1 acts as an efficient electrocatalyst for the hydrogen evolution reaction (HER) as well as an effective proton conductor in comparison to the performance of compound 2. The HER activity of compound 1 is characterized by an overpotential of 340 mV@1 mA cm-2 and a low Tafel slope of 75 mV/decade. The catalyst (compound 1) displays a Faradaic efficiency of 88% with a turnover frequency of 2.9 s-1. The proton conductivity value of this compound (1) is determined to be 4.9 × 10-3 S cm-1 at 55 °C under 98% relative humidity; the relevant proton conduction is operated by the Grotthuss mechanism with an activation energy of 0.17 eV.
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Affiliation(s)
- Gopika Premanand
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
| | - Debu Jana
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
| | | | - Samar K Das
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
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Nor-Azman NA, Ghasemian MB, Fuchs R, Liu L, Widjajana MS, Yu R, Chiu SH, Idrus-Saidi SA, Flores N, Chi Y, Tang J, Kalantar-Zadeh K. Mechanism behind the Controlled Generation of Liquid Metal Nanoparticles by Mechanical Agitation. ACS NANO 2024; 18:11139-11152. [PMID: 38620061 DOI: 10.1021/acsnano.3c12638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
The size-controlled synthesis of liquid metal nanoparticles is necessary in a variety of applications. Sonication is a common method for breaking down bulk liquid metals into small particles, yet the influence of critical factors such as liquid metal composition has remained elusive. Our study employs high-speed imaging to unravel the mechanism of liquid metal particle formation during mechanical agitation. Gallium-based liquid metals, with and without secondary metals of bismuth, indium, and tin, are analyzed to observe the effect of cavitation and surface eruption during sonication and particle release. The impact of the secondary metal inclusion is investigated on liquid metals' surface tension, solution turbidity, and size distribution of the generated particles. Our work evidences that there is an inverse relationship between the surface tension and the ability of liquid metals to be broken down by sonication. We show that even for 0.22 at. % of bismuth in gallium, the surface tension is significantly decreased from 558 to 417 mN/m (measured in Milli-Q water), resulting in an enhanced particle generation rate: 3.6 times increase in turbidity and ∼43% reduction in the size of particles for bismuth in gallium liquid alloy compared to liquid gallium for the same sonication duration. The effect of particles' size on the photocatalysis of the annealed particles is also presented to show the applicability of the process in a proof-of-concept demonstration. This work contributes to a broader understanding of the synthesis of nanoparticles, with controlled size and characteristics, via mechanical agitation of liquid metals for diverse applications.
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Affiliation(s)
- Nur-Adania Nor-Azman
- School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, NSW 2008, Australia
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Mohammad B Ghasemian
- School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, NSW 2008, Australia
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Richard Fuchs
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Li Liu
- School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, NSW 2008, Australia
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Moonika S Widjajana
- School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, NSW 2008, Australia
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Ruohan Yu
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Shih-Hao Chiu
- School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, NSW 2008, Australia
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Shuhada A Idrus-Saidi
- Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, Skudai, Johor Bahru, Johor 81310, Malaysia
- Centre of Lipids Engineering and Applied Research (CLEAR), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Skudai, Johor Bahru, Johor 81310, Malaysia
| | - Nieves Flores
- School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, NSW 2008, Australia
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Yuan Chi
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Jianbo Tang
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Kourosh Kalantar-Zadeh
- School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, NSW 2008, Australia
- School of Chemical Engineering, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
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Bhagwat S, Hambitzer L, Prediger R, Zhu P, Hamza A, Kilian SK, Kluck S, Pezeshkpour P, Kotz-Helmer F, Rapp BE. Tungsten Oxide Coated Liquid Metal Electrodes via Galvanic Replacement as Heavy Metal Ion Sensors. SENSORS (BASEL, SWITZERLAND) 2024; 24:416. [PMID: 38257509 PMCID: PMC10819474 DOI: 10.3390/s24020416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024]
Abstract
Gallium liquid metals (LMs) like Galinstan and eutectic Gallium-Indium (EGaIn) have seen increasing applications in heavy metal ion (HMI) sensing, because of their ability to amalgamate with HMIs like lead, their high hydrogen potential, and their stable electrochemical window. Furthermore, coating LM droplets with nanopowders of tungsten oxide (WO) has shown enhancement in HMI sensing owing to intense electrical fields at the nanopowder-liquid-metal interface. However, most LM HMI sensors are droplet based, which show limitations in scalability and the homogeneity of the surface. A scalable approach that can be extended to LM electrodes is therefore highly desirable. In this work, we present, for the first time, WO-Galinstan HMI sensors fabricated via photolithography of a negative cavity, Galinstan brushing inside the cavity, lift-off, and galvanic replacement (GR) in a tungsten salt solution. Successful GR of Galinstan was verified using optical microscopy, SEM, EDX, XPS, and surface roughness measurements of the Galinstan electrodes. The fabricated WO-Galinstan electrodes demonstrated enhanced sensitivity in comparison with electrodes structured from pure Galinstan and detected lead at concentrations down to 0.1 mmol·L-1. This work paves the way for a new class of HMI sensors using GR of WO-Galinstan electrodes, with applications in microfluidics and MEMS for a toxic-free environment.
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Affiliation(s)
- Sagar Bhagwat
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
| | - Leonhard Hambitzer
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
| | - Richard Prediger
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
| | - Pang Zhu
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
| | - Ahmed Hamza
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
| | - Sophia K. Kilian
- Hahn-Schickard, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany;
| | - Sebastian Kluck
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
| | - Pegah Pezeshkpour
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
| | - Frederik Kotz-Helmer
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
- Freiburg Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Straße 21, 79104 Freiburg im Breisgau, Germany
| | - Bastian E. Rapp
- Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany; (S.B.); (L.H.); (R.P.); (P.Z.); (A.H.); (S.K.); (P.P.); (B.E.R.)
- Freiburg Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Straße 21, 79104 Freiburg im Breisgau, Germany
- FIT Freiburg Center of Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg im Breisgau, Germany
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