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Cao S, Chen N, Li M, Wei K, Zhan G, Guo F, Gao T, Jia F, Zhang L. Construction of an OCP-ATR-FTIR Spectroscopy Device to In Situ Monitor the Interfacial Reaction of Contaminants: Competitive Adsorption of Cr(VI) and Oxalate on Hematite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16532-16540. [PMID: 37853668 DOI: 10.1021/acs.est.3c04475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
The comprehensive understanding of contaminant interfacial behavior strongly depends on the in situ characterization technique, which is still a great challenge. In this study, we constructed a device integrated with open-circuit potentialand attenuated total reflectance Fourier transform infrared (OCP-ATR-FTIR) spectroscopy to simultaneously monitor the electrochemical and infrared spectral information on the interfacial reaction for the process analysis, taking the competitive adsorption of hexavalent chromium (Cr(VI)) and oxalate on hematite nanocubes (HNC) as an example. The synchronous OCP and infrared results revealed that Cr(VI) interacted with HNC via bidentate binuclear inner-sphere coordination, accompanied by electron transfer from HNC to Cr(VI), while oxalate was adsorbed on HNC through bidentate mononuclear side-on inner-sphere coordination with electron transfer from HNC to oxalate, and also outer-sphere coordination with negative charge accumulation. When oxalate was added to HNC with preadsorbed Cr(VI), oxalate would occupy the inner-sphere adsorption sites and thus cause the detaching of preadsorbed Cr(VI) from HNC. This study provides a promising in situ characterization technique for real-time interfacial reaction monitoring and also sheds light on the competitive adsorption mechanism of oxalate and Cr(VI) on the mineral surface.
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Affiliation(s)
- Shiyu Cao
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Na Chen
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Meiqi Li
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Kai Wei
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Guangming Zhan
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Furong Guo
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Tingjuan Gao
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Falong Jia
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Lizhi Zhang
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
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Wu KH, Zhang J, Amdad Ali M, Zhao S. Rotating ring-disc electrode method: Assessing transient chemical interaction of redox intermediate with electrode surface. J Electroanal Chem (Lausanne) 2023. [DOI: 10.1016/j.jelechem.2023.117317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
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Jetmore HD, Anupriya ES, Cress TJ, Shen M. Interface between Two Immiscible Electrolyte Solutions Electrodes for Chemical Analysis. Anal Chem 2022; 94:16519-16527. [DOI: 10.1021/acs.analchem.2c01416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Henry David Jetmore
- University of Illinois at Urbana−Champaign, Urbana, Illinois61801, United States
| | | | - Tanner Joe Cress
- University of Illinois at Urbana−Champaign, Urbana, Illinois61801, United States
| | - Mei Shen
- University of Illinois at Urbana−Champaign, Urbana, Illinois61801, United States
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Finney AR, McPherson IJ, Unwin PR, Salvalaglio M. Electrochemistry, ion adsorption and dynamics in the double layer: a study of NaCl(aq) on graphite. Chem Sci 2021; 12:11166-11180. [PMID: 34522314 PMCID: PMC8386640 DOI: 10.1039/d1sc02289j] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 07/14/2021] [Indexed: 12/18/2022] Open
Abstract
Graphite and related sp2 carbons are ubiquitous electrode materials with particular promise for use in e.g., energy storage and desalination devices, but very little is known about the properties of the carbon–electrolyte double layer at technologically relevant concentrations. Here, the (electrified) graphite–NaCl(aq) interface was examined using constant chemical potential molecular dynamics (CμMD) simulations; this approach avoids ion depletion (due to surface adsorption) and maintains a constant concentration, electroneutral bulk solution beyond the surface. Specific Na+ adsorption at the graphite basal surface causes charging of the interface in the absence of an applied potential. At moderate bulk concentrations, this leads to accumulation of counter-ions in a diffuse layer to balance the effective surface charge, consistent with established models of the electrical double layer. Beyond ∼0.6 M, however, a combination of over-screening and ion crowding in the double layer results in alternating compact layers of charge density perpendicular to the interface. The transition to this regime is marked by an increasing double layer size and anomalous negative shifts to the potential of zero charge with incremental changes to the bulk concentration. Our observations are supported by changes to the position of the differential capacitance minimum measured by electrochemical impedance spectroscopy, and are explained in terms of the screening behaviour and asymmetric ion adsorption. Furthermore, a striking level of agreement between the differential capacitance from solution evaluated in simulations and measured in experiments allows us to critically assess electrochemical capacitance measurements which have previously been considered to report simply on the density of states of the graphite material at the potential of zero charge. Our work shows that the solution side of the double layer provides the more dominant contribution to the overall measured capacitance. Finally, ion crowding at the highest concentrations (beyond ∼5 M) leads to the formation of liquid-like NaCl clusters confined to highly non-ideal regions of the double layer, where ion diffusion is up to five times slower than in the bulk. The implications of changes to the speciation of ions on reactive events in the double layer are discussed. CμMD reveals multi-layer electrolyte screening in the double layer beyond 0.6 M, which affects ion activities, speciation and mobility; asymmetric charge screening explains concentration dependent changes to electrochemical properties.![]()
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Affiliation(s)
- Aaron R Finney
- Thomas Young Centre and Department of Chemical Engineering, University College London London WC1E 7JE UK
| | - Ian J McPherson
- Department of Chemistry, University of Warwick Coventry CV4 7AL UK
| | - Patrick R Unwin
- Department of Chemistry, University of Warwick Coventry CV4 7AL UK
| | - Matteo Salvalaglio
- Thomas Young Centre and Department of Chemical Engineering, University College London London WC1E 7JE UK
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Bhattacharyya D, Videla PE, Cattaneo M, Batista VS, Lian T, Kubiak CP. Vibrational Stark shift spectroscopy of catalysts under the influence of electric fields at electrode-solution interfaces. Chem Sci 2021; 12:10131-10149. [PMID: 34377403 PMCID: PMC8336477 DOI: 10.1039/d1sc01876k] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 07/13/2021] [Indexed: 11/24/2022] Open
Abstract
External control of chemical processes is a subject of widespread interest in chemical research, including control of electrocatalytic processes with significant promise in energy research. The electrochemical double-layer is the nanoscale region next to the electrode/electrolyte interface where chemical reactions typically occur. Understanding the effects of electric fields within the electrochemical double layer requires a combination of synthesis, electrochemistry, spectroscopy, and theory. In particular, vibrational sum frequency generation (VSFG) spectroscopy is a powerful technique to probe the response of molecular catalysts at the electrode interface under bias. Fundamental understanding can be obtained via synthetic tuning of the adsorbed molecular catalysts on the electrode surface and by combining experimental VSFG data with theoretical modelling of the Stark shift response. The resulting insights at the molecular level are particularly valuable for the development of new methodologies to control and characterize catalysts confined to electrode surfaces. This Perspective article is focused on how systematic modifications of molecules anchored to surfaces report information concerning the geometric, energetic, and electronic parameters of catalysts under bias attached to electrode surfaces. Heterogeneous electrocatalysis: characterization of interfacial electric field within the electrochemical double layer.![]()
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Affiliation(s)
- Dhritiman Bhattacharyya
- Department of Chemistry, Emory University 1515 Dickey Drive Northeast Atlanta Georgia 30322 USA
| | - Pablo E Videla
- Department of Chemistry and Energy Sciences Institute, Yale University 225 Prospect Street New Haven Connecticut 06520 USA
| | - Mauricio Cattaneo
- INQUINOA-UNT-CONICET, Facultad de Bioquímica, Química y Farmacia, Instituto de Química Física, Universidad Nacional de Tucumán Ayacucho 471 (4000) San Miguel de Tucumán Argentina
| | - Victor S Batista
- Department of Chemistry and Energy Sciences Institute, Yale University 225 Prospect Street New Haven Connecticut 06520 USA
| | - Tianquan Lian
- Department of Chemistry, Emory University 1515 Dickey Drive Northeast Atlanta Georgia 30322 USA
| | - Clifford P Kubiak
- Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, MC 0358 La Jolla California 92093 USA
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Bossa GV, May S. Debye-Hückel Free Energy of an Electric Double Layer with Discrete Charges Located at a Dielectric Interface. MEMBRANES 2021; 11:129. [PMID: 33672797 PMCID: PMC7918844 DOI: 10.3390/membranes11020129] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 01/31/2021] [Accepted: 02/05/2021] [Indexed: 11/25/2022]
Abstract
Poisson-Boltzmann theory provides an established framework to calculate properties and free energies of an electric double layer, especially for simple geometries and interfaces that carry continuous charge densities. At sufficiently small length scales, however, the discreteness of the surface charges cannot be neglected. We consider a planar dielectric interface that separates a salt-containing aqueous phase from a medium of low dielectric constant and carries discrete surface charges of fixed density. Within the linear Debye-Hückel limit of Poisson-Boltzmann theory, we calculate the surface potential inside a Wigner-Seitz cell that is produced by all surface charges outside the cell using a Fourier-Bessel series and a Hankel transformation. From the surface potential, we obtain the Debye-Hückel free energy of the electric double layer, which we compare with the corresponding expression in the continuum limit. Differences arise for sufficiently small charge densities, where we show that the dominating interaction is dipolar, arising from the dipoles formed by the surface charges and associated counterions. This interaction propagates through the medium of a low dielectric constant and alters the continuum power of two dependence of the free energy on the surface charge density to a power of 2.5 law.
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Affiliation(s)
- Guilherme Volpe Bossa
- Department of Physics, Institute of Biosciences, Humanities and Exact Sciences, São Paulo State University (UNESP), São José do Rio Preto 15054-000, Brazil;
| | - Sylvio May
- Department of Physics, North Dakota State University, Fargo North Dakota, ND 58108-6050, USA
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