1
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Su S, Siretanu I, van den Ende D, Mei B, Mul G, Mugele F. Nanometer-Resolved Operando Photo-Response of Faceted BiVO 4 Semiconductor Nanoparticles. J Am Chem Soc 2024; 146:2248-2256. [PMID: 38214667 PMCID: PMC10811660 DOI: 10.1021/jacs.3c12666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/13/2024]
Abstract
Photo(electro)catalysis with semiconducting nanoparticles (NPs) is an attractive approach to convert abundant but intermittent renewable electricity into stable chemical fuels. However, our understanding of the microscopic processes governing the performance of the materials has been hampered by the lack of operando characterization techniques with sufficient lateral resolution. Here, we demonstrate that the local surface potentials of NPs of bismuth vanadate (BiVO4) and their response to illumination differ between adjacent facets and depend strongly on the pH of the ambient electrolyte. The isoelectric points of the dominant {010} basal plane and the adjacent {110} side facets differ by 1.5 pH units. Upon illumination, both facets accumulate positive charges and display a maximum surface photoresponse of +55 mV, much stronger than reported in the literature for the surface photo voltage of BiVO4 NPs in air. High resolution images reveal the presence of numerous surface defects ranging from vacancies of a few atoms, to single unit cell steps, to microfacets of variable orientation and degree of disorder. These defects typically carry a highly localized negative surface charge density and display an opposite photoresponse compared to the adjacent facets. Strategies to model and optimize the performance of photocatalyst NPs, therefore, require an understanding of the distribution of surface defects, including the interaction with ambient electrolyte.
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Affiliation(s)
- Shaoqiang Su
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
| | - Igor Siretanu
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
| | - Dirk van den Ende
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
| | - Bastian Mei
- Photocatalytic
Synthesis Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Guido Mul
- Photocatalytic
Synthesis Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Frieder Mugele
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
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2
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Siretanu I, van Lin SR, Mugele F. Ion adsorption and hydration forces: a comparison of crystalline mica vs. amorphous silica surfaces. Faraday Discuss 2023; 246:274-295. [PMID: 37408390 PMCID: PMC10568262 DOI: 10.1039/d3fd00049d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 03/13/2023] [Indexed: 10/13/2023]
Abstract
Hydration forces are ubiquitous in nature and technology. Yet, the characterization of interfacial hydration structures and their dependence on the nature of the substrate and the presence of ions have remained challenging and controversial. We present a systematic study using dynamic Atomic Force Microscopy of hydration forces on mica surfaces and amorphous silica surfaces in aqueous electrolytes containing chloride salts of various alkali and earth alkaline cations of variable concentrations at pH values between 3 and 9. Our measurements with ultra-sharp AFM tips demonstrate the presence of both oscillatory and monotonically decaying hydration forces of very similar strength on both atomically smooth mica and amorphous silica surfaces with a roughness comparable to the size of a water molecule. The characteristic range of the forces is approximately 1 nm, independent of the fluid composition. Force oscillations are consistent with the size of water molecules for all conditions investigated. Weakly hydrated Cs+ ions are the only exception: they disrupt the oscillatory hydration structure and induce attractive monotonic hydration forces. On silica, force oscillations are also smeared out if the size of the AFM tip exceeds the characteristic lateral scale of the surface roughness. The observation of attractive monotonic hydration forces for asymmetric systems suggests opportunities to probe water polarization.
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Affiliation(s)
- Igor Siretanu
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
| | - Simone R van Lin
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
| | - Frieder Mugele
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
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3
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Ho TA, Rosso KM, Criscenti LJ. Atomistic Mismatch Defines Energy-Structure Relationships during Oriented Attachment of Nanoparticles. J Phys Chem Lett 2022; 13:9339-9347. [PMID: 36179321 DOI: 10.1021/acs.jpclett.2c02511] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Oriented attachment is an important crystal growth pathway in nature and has been extensively exploited to develop hierarchically structured crystalline materials. Atomistic mismatch in the crystal structure of two particles in the solvent-separated state creates forces that drive particle motions enabling solvent expulsion and coalescence, but the relative magnitudes of the energy barriers for approach, rotation, and translation are not well-known. Here we use classical molecular simulations to calculate the potential of mean force for these three different motions for basal surface encounters of gibbsite nanoplatelets separated by one water layer. In all cases, the highest energy barrier is associated with removing this last water layer to enable jump to contact, even when coaligned. Mutual rotation is more probable than sliding motion, which are both much more probable than jump to contact. This work provides the first comparison on an equal footing of the energy-structure relationships for multiple alignment paths between solvent-separated particles in bulk aqueous solution.
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Affiliation(s)
- Tuan A Ho
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico87185, United States
| | - Kevin M Rosso
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington99352, United States
| | - Louise J Criscenti
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico87185, United States
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4
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Kumar S, Cats P, Alotaibi MB, Ayirala SC, Yousef AA, van Roij R, Siretanu I, Mugele F. Absence of anomalous underscreening in highly concentrated aqueous electrolytes confined between smooth silica surfaces. J Colloid Interface Sci 2022; 622:819-827. [PMID: 35561602 DOI: 10.1016/j.jcis.2022.05.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/08/2022] [Accepted: 05/01/2022] [Indexed: 10/18/2022]
Abstract
Recent surface forces apparatus experiments that measured the forces between two mica surfaces and a series of subsequent theoretical studies suggest the occurrence of universal underscreening in highly concentrated electrolyte solutions. We performed a set of systematic Atomic Force Spectroscopy measurements for aqueous salt solutions in a concentration range from 1 mM to 5 M using chloride salts of various alkali metals as well as mixed concentrated salt solutions (involving both mono- and divalent cations and anions), that mimic concentrated brines typically encountered in geological formations. Experiments were carried out using flat substrates and submicrometer-sized colloidal probes made of smooth oxidized silicon immersed in salt solutions at pH values of 6 and 9 and temperatures of 25 °C and 45 °C. While strong repulsive forces were observed for the smallest tip-sample separations, none of the conditions explored displayed any indication of anomalous long range electrostatic forces as reported for mica surfaces. Instead, forces are universally dominated by attractive van der Waals interactions at tip-sample separations of ≈2 nm and beyond for salt concentrations of 1 M and higher. Complementary calculations based on classical density functional theory for the primitive model support these experimental observations and display a consistent decrease in screening length with increasing ion concentration.
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Affiliation(s)
- Saravana Kumar
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, the Netherlands
| | - Peter Cats
- Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, the Netherlands
| | - Mohammed B Alotaibi
- The Exploration and Petroleum Engineering Center - Advanced Research Center (EXPEC ARC), Saudi Aramco, Dhahran 34465, Saudi Arabia
| | - Subhash C Ayirala
- The Exploration and Petroleum Engineering Center - Advanced Research Center (EXPEC ARC), Saudi Aramco, Dhahran 34465, Saudi Arabia
| | - Ali A Yousef
- The Exploration and Petroleum Engineering Center - Advanced Research Center (EXPEC ARC), Saudi Aramco, Dhahran 34465, Saudi Arabia
| | - René van Roij
- Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, the Netherlands
| | - Igor Siretanu
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, the Netherlands
| | - Frieder Mugele
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, the Netherlands
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5
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Legg BA, Voïtchovsky K, De Yoreo JJ. Hydroxide films on mica form charge-stabilized microphases that circumvent nucleation barriers. SCIENCE ADVANCES 2022; 8:eabn7087. [PMID: 36054353 PMCID: PMC10848954 DOI: 10.1126/sciadv.abn7087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Crystal nucleation is facilitated by transient, nanoscale fluctuations that are extraordinarily difficult to observe. Here, we use high-speed atomic force microscopy to directly observe the growth of an aluminum hydroxide film from an aqueous solution and characterize the dynamically fluctuating nanostructures that precede its formation. Nanoscale cluster distributions and fluctuation dynamics show many similarities to the predictions of classical nucleation theory, but the cluster energy landscape deviates from classical expectations. Kinetic Monte Carlo simulations show that these deviations can arise from electrostatic interactions between the clusters and the underlying substrate, which drive microphase separation to create a nanostructured surface phase. This phase can evolve seamlessly from a low-coverage state of fluctuating clusters into a high-coverage nanostructured network, allowing the film to grow without having to overcome classical nucleation barriers.
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Affiliation(s)
- Benjamin A. Legg
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
| | | | - James J. De Yoreo
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
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6
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Liu W, Pouvreau M, Stack AG, Yang X, Clark AE. Concentration dependent interfacial chemistry of the NaOH (aq): gibbsite interface. Phys Chem Chem Phys 2022; 24:20998-21008. [PMID: 36000443 DOI: 10.1039/d2cp01997c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Caustic conditions are often employed for dissolution of a wide variety of minerals, where ion sorption, surface diffusion, and interfacial organization impact surface reactivity. In the case of gibbsite, γ-Al(OH)3, the chemistry at the NaOH(aq) interface is deeply intertwined with industrial processing of aluminum, including metal production and the disposition of Al-containing wastes. To date, little is known about the structure, speciation, and dynamic behavior of gibbsite interfaces (and that of many other minerals) with NaOH(aq)-particularly as a function of ionic strength. Yet concentration-dependent interfacial organization and dynamics are a critical starting point to develop a fundamental understanding of the factors that influence dissolution. This work reports equilibrium molecular dynamics simulations of the γ-Al(OH)3:NaOH(aq) interface, revealing the sorption behavior and speciation of ions from 0.5-10 M [NaOH]. As inner-sphere complexes, Na+ primarily coordinates to the side of the gibbsite hexagonal cavities, while OH- accepts hydrogen-bonding from the surface-OH groups. The mobility of inner-sphere Na+ and OH- ions is significantly reduced due to a strong surface affinity in comparison to previous reports of NaCl, CaCl2, or BaCl2 electrolytes. At high [NaOH], contact ion pairing that is observed in the bulk solution is partially disrupted upon sorption to the gibbsite surface by the individual ion-surface interactions. The molecular-scale changes to surface speciation and competition between ion-surface vs. ion-ion interactions influence surface characterization of gibbsite and potential dissolution processes, providing a valuable baseline for starting conditions needed within future reactive molecular simulations.
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Affiliation(s)
- Wei Liu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Maxime Pouvreau
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA.
| | | | - Xiaoning Yang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Aurora E Clark
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA.
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7
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Feng B, Li Y, Li R, Li H. Error analysis in calculation and interpretation of AFM tip-surface interaction forces. Adv Colloid Interface Sci 2022; 306:102710. [PMID: 35691096 DOI: 10.1016/j.cis.2022.102710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 05/22/2022] [Accepted: 05/29/2022] [Indexed: 11/01/2022]
Abstract
This review addresses some possible errors in calculation and interpretation of AFM tip-surface interaction forces. These usually ignored errors can affect the accuracy and correctness of the interpretation results obtained from measured interaction forces, thus hindering the application of AFM technology in related fields of colloid and interface science. Based on comprehensive analysis and assessment, three important aspects in the existing literature that may introduce significant errors in calculation and interpretation of AFM tip-surface interaction forces have been identified, and corresponding reasonable suggestions have been proposed. (1) The frequently used over-approximated electrostatic force formulas can cause great errors in the electrostatic force and the fitting of surface potential and surface charge density. Therefore, adequate electrostatic force calculation methods, like linear superposition approximation (LSA) or exact numerical solutions, should be used. (2) The over-approximated AFM tip-surface interaction models (spherical tip and flat tip-flat surface interaction models (s-f and f-f)) will lead to large errors in the electrostatic force and van der Waals force, and the subsequently fitted surface potential, surface charge density, and Hamaker constant. Therefore, the conical tip with spherical end and the conical tip with flat circular end-flat surface interaction models (cs-f and cf-f) rather than the over-approximated models (s-f and f-f) should be applied. Besides, it is recommended to use cf-f instead of cs-f to measure the interaction forces for more accuracy. (3) The inaccurately obtained (usually by SEM image) AFM tip geometry parameters (radius and half angle) have significant impacts on the fitting results of surface potential, surface charge density, and Hamaker constant. More accurate AFM tip geometry parameters and reasonable assessment of errors in calculation and interpretation are necessary.
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8
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Klaassen A, Liu F, Mugele F, Siretanu I. Correlation between Electrostatic and Hydration Forces on Silica and Gibbsite Surfaces: An Atomic Force Microscopy Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:914-926. [PMID: 35025512 PMCID: PMC8793142 DOI: 10.1021/acs.langmuir.1c02077] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 12/29/2021] [Indexed: 06/14/2023]
Abstract
The balance between hydration and Derjaguin-Landau-Verwey-Overbeek (DLVO) forces at solid-liquid interfaces controls many processes, such as colloidal stability, wetting, electrochemistry, biomolecular self-assembly, and ion adsorption. Yet, the origin of molecular scale hydration forces and their relation to the surface charge density that controls the continuum scale electrostatic forces is poorly understood. We argue that these two types of forces are largely independent of each other. To support this hypothesis, we performed atomic force microscopy experiments using intermediate-sized tips that enable the simultaneous detection of DLVO and molecular scale oscillatory hydration forces at the interface between composite gibbsite:silica-aqueous electrolyte interfaces. We extract surface charge densities from forces measured at tip-sample separations of 1.5 nm and beyond using DLVO theory in combination with charge regulation boundary conditions for various pH values and salt concentrations. We simultaneously observe both colloidal scale DLVO forces and oscillatory hydration forces for an individual crystalline gibbsite particle and the underlying amorphous silica substrate for all fluid compositions investigated. While the diffuse layer charge varies with pH as expected, the oscillatory hydration forces are found to be largely independent of pH and salt concentration, supporting our hypothesis that both forces indeed have a very different origin. Oscillatory hydration forces are found to be distinctly more pronounced on gibbsite than on silica. We rationalize this observation based on the distribution of hydroxyl groups available for H bonding on the two distinct surfaces.
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Affiliation(s)
- Aram Klaassen
- Physics of Complex Fluids Group and
MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Fei Liu
- Physics of Complex Fluids Group and
MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Frieder Mugele
- Physics of Complex Fluids Group and
MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Igor Siretanu
- Physics of Complex Fluids Group and
MESA+ Institute, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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9
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Su S, Siretanu I, van den Ende D, Mei B, Mul G, Mugele F. Facet-Dependent Surface Charge and Hydration of Semiconducting Nanoparticles at Variable pH. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2106229. [PMID: 34609757 DOI: 10.1002/adma.202106229] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Understanding structure and function of solid-liquid interfaces is essential for the development of nanomaterials for various applications including heterogeneous catalysis in liquid phase processes and water splitting for storage of renewable electricity. The characteristic anisotropy of crystalline nanoparticles is believed to be essential for their performance but remains poorly understood and difficult to characterize. Dual scale atomic force microscopy is used to measure electrostatic and hydration forces of faceted semiconducting SrTiO3 nanoparticles in aqueous electrolyte at variable pH. The following are demonstrated: the ability to quantify strongly facet-dependent surface charges yielding isoelectric points of the dominant {100} and {110} facets that differ by as much as 2 pH units; facet-dependent accumulation of oppositely charged (SiO2 ) particles; and that atomic scale defects can be resolved but are in fact rare for the samples investigated. Atomically resolved images and facet-dependent oscillatory hydration forces suggest a microscopic charge generation mechanism that explains colloidal scale electrostatic forces.
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Affiliation(s)
- Shaoqiang Su
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Igor Siretanu
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Dirk van den Ende
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Bastian Mei
- Photocatalytic Synthesis Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Guido Mul
- Photocatalytic Synthesis Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
| | - Frieder Mugele
- Physics of Complex Fluids Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, The Netherlands
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10
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Yalcin SE, Legg BA, Yeşilbaş M, Malvankar NS, Boily JF. Direct observation of anisotropic growth of water films on minerals driven by defects and surface tension. SCIENCE ADVANCES 2020; 6:eaaz9708. [PMID: 32832658 PMCID: PMC7439304 DOI: 10.1126/sciadv.aaz9708] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 06/10/2020] [Indexed: 05/10/2023]
Abstract
Knowledge of the occurrences of water films on minerals is critical for global biogeochemical and atmospheric processes, including element cycling and ice nucleation. The underlying mechanisms controlling water film growth are, however, misunderstood. Using infrared nanospectroscopy, amplitude-modulated atomic force microscopy, and molecular simulations, we show how water films grow from water vapor on hydrophilic mineral nanoparticles. We imaged films with up to four water layers that grow anisotropically over a single face. Growth usually begins from the near edges of a face where defects preferentially capture water vapor. Thicker films produced by condensation cooling completely engulf nanoparticles and form thicker menisci over defects. The high surface tension of water smooths film surfaces and produces films of inhomogeneous thickness. Nanoscale topography and film surface energy thereby control anisotropic distributions and thicknesses of water films on hydrophilic mineral nanoparticles.
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Affiliation(s)
- Sibel Ebru Yalcin
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Benjamin A. Legg
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
| | - Merve Yeşilbaş
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Nikhil S. Malvankar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
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11
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van Lin S, Grotz KK, Siretanu I, Schwierz N, Mugele F. Ion-Specific and pH-Dependent Hydration of Mica-Electrolyte Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5737-5745. [PMID: 30974056 PMCID: PMC6495383 DOI: 10.1021/acs.langmuir.9b00520] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/05/2019] [Indexed: 05/05/2023]
Abstract
Hydration forces play a crucial role in a wide range of phenomena in physics, chemistry, and biology. Here, we study the hydration of mica surfaces in contact with various alkali chloride solutions over a wide range of concentrations and pH values. Using atomic force microscopy and molecular dynamics simulations, we demonstrate that hydration forces consist of a superposition of a monotonically decaying and an oscillatory part, each with a unique dependence on the specific type of cation. The monotonic hydration force gradually decreases in strength with decreasing bulk hydration energy, leading to a transition from an overall repulsive (Li+, Na+) to an attractive (Rb+, Cs+) force. The oscillatory part, in contrast, displays a binary character, being hardly affected by the presence of strongly hydrated cations (Li+, Na+), but it becomes completely suppressed in the presence of weakly hydrated cations (Rb+, Cs+), in agreement with a less pronounced water structure in simulations. For both aspects, K+ plays an intermediate role, and decreasing pH follows the trend of increasing Rb+ and Cs+ concentrations.
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Affiliation(s)
- Simone
R. van Lin
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Kara K. Grotz
- Department
of Theoretical Biophysics, Max Planck Institute
of Biophysics, Max-von-Laue-Straße
3, 60438 Frankfurt
(Main), Germany
| | - Igor Siretanu
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Nadine Schwierz
- Department
of Theoretical Biophysics, Max Planck Institute
of Biophysics, Max-von-Laue-Straße
3, 60438 Frankfurt
(Main), Germany
| | - Frieder Mugele
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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12
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Ozcelik HG, Barisik M. Electric charge of nanopatterned silica surfaces. Phys Chem Chem Phys 2019; 21:7576-7587. [DOI: 10.1039/c9cp00706g] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The surface charge density of a nanopatterned silica decreased at the pits but increased at the tips of surface patterns. For a case of self-repeating surface structures, the average of local surface charges becomes lower than the theoretical predictions. Our phenomenological model developed as an extension to the existing flat surface theory predicts the average surface charge on a nanopatterned surface as a function of surface pattern size, ionic concentration and pH.
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Affiliation(s)
- H. Gokberk Ozcelik
- Department of Mechanical Engineering
- Izmir Institute of Technology
- IZMIR
- Turkey
| | - Murat Barisik
- Department of Mechanical Engineering
- Izmir Institute of Technology
- IZMIR
- Turkey
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13
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Ho TA, Greathouse JA, Lee AS, Criscenti LJ. Enhanced Ion Adsorption on Mineral Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5926-5934. [PMID: 29746135 DOI: 10.1021/acs.langmuir.8b00680] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Classical molecular dynamics simulation was used to study the adsorption of Na+, Ca2+, Ba2+, and Cl- ions on gibbsite edge (1 0 0), basal (0 0 1), and nanoparticle (NP) surfaces. The gibbsite NP consists of both basal and edge surfaces. Simulation results indicate that Na+ and Cl- ions adsorb on both (1 0 0) and (0 0 1) surfaces as inner-sphere species (i.e., no water molecules between an ion and the surface). Outer-sphere Cl- ions (i.e., one water molecule between an ion and the surface) were also found on these surfaces. On the (1 0 0) edge, Ca2+ ions adsorb as inner-sphere and outer-sphere complexes, whereas on the (0 0 1) surface, outer-sphere Ca2+ ions are the dominant species. Ba2+ ions were found as inner-sphere and outer-sphere complexes on both surfaces. Calculated ion surface coverages indicate that, for all ions, surface coverages are always higher on the basal surface compared to those on the edge surface. More importantly, surface coverages for cations on the gibbsite NP are always higher than those calculated for the (1 0 0) and (0 0 1) surfaces. This enhanced ion adsorption behavior for the NP is due to the significant number of inner-sphere cations found at NP corners. Outer-sphere cations do not contribute to the enhanced surface coverage. In addition, there is no ion adsorption enhancement observed for the Cl- ion. Our work provides a molecular-scale understanding of the relative significance of ion adsorption onto gibbsite basal versus edge surfaces and demonstrates the corner effect on ion adsorption on NPs.
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Affiliation(s)
- Tuan A Ho
- Geochemistry Department , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Jeffery A Greathouse
- Geochemistry Department , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Andrew S Lee
- Geochemistry Department , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Louise J Criscenti
- Geochemistry Department , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
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Liu F, Klaassen A, Zhao C, Mugele F, van den Ende D. Electroviscous Dissipation in Aqueous Electrolyte Films with Overlapping Electric Double Layers. J Phys Chem B 2018; 122:933-946. [PMID: 28976197 PMCID: PMC5776519 DOI: 10.1021/acs.jpcb.7b07019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/19/2017] [Indexed: 01/16/2023]
Abstract
We use dynamic atomic force microscopy (AFM) to investigate the forces involved in squeezing out thin films of aqueous electrolyte between an AFM tip and silica substrates at variable pH and salt concentration. From amplitude and phase of the AFM signal we determine both conservative and dissipative components of the tip sample interaction forces. The measured dissipation is enhanced by up to a factor of 5 at tip-sample separations of ≈ one Debye length compared to the expectations based on classical hydrodynamic Reynolds damping with bulk viscosity. Calculating the surface charge density from the conservative forces using Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in combination with a charge regulation boundary condition we find that the viscosity enhancement correlates with increasing surface charge density. We compare the observed viscosity enhancement with two competing continuum theory models: (i) electroviscous dissipation due to the electrophoretic flow driven by the streaming current that is generated upon squeezing out the counterions in the diffuse part of the electric double layer, and (ii) visco-electric enhancement of the local water viscosity caused by the strong electric fields within the electric double layer. While the visco-electric model correctly captures the qualitative trends observed in the experiments, a quantitative description of the data presumably requires more sophisticated simulations that include microscopic aspects of the distribution and mobility of ions in the Stern layer.
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Affiliation(s)
- F. Liu
- Physics of Complex Fluids, MESA+ Institute for Nanotechnology University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - A. Klaassen
- Physics of Complex Fluids, MESA+ Institute for Nanotechnology University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - C. Zhao
- Physics of Complex Fluids, MESA+ Institute for Nanotechnology University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - F. Mugele
- Physics of Complex Fluids, MESA+ Institute for Nanotechnology University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - D. van den Ende
- Physics of Complex Fluids, MESA+ Institute for Nanotechnology University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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15
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Lützenkirchen J, Franks G, Plaschke M, Zimmermann R, Heberling F, Abdelmonem A, Darbha G, Schild D, Filby A, Eng P, Catalano J, Rosenqvist J, Preocanin T, Aytug T, Zhang D, Gan Y, Braunschweig B. The surface chemistry of sapphire-c: A literature review and a study on various factors influencing its IEP. Adv Colloid Interface Sci 2018; 251:1-25. [PMID: 29287789 DOI: 10.1016/j.cis.2017.12.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 12/11/2017] [Accepted: 12/11/2017] [Indexed: 10/18/2022]
Abstract
A wide range of isoelectric points (IEPs) has been reported in the literature for sapphire-c (α-alumina), also referred to as basal plane, (001) or (0001), single crystals. Interestingly, the available data suggest that the variation of IEPs is comparable to the range of IEPs encountered for particles, although single crystals should be much better defined in terms of surface structure. One explanation for the range of IEPs might be the obvious danger of contaminating the small surface areas of single crystal samples while exposing them to comparatively large solution reservoirs. Literature suggests that factors like origin of the sample, sample treatment or the method of investigation all have an influence on the surfaces and it is difficult to clearly separate the respective, individual effects. In the present study, we investigate cause-effect relationships to better understand the individual effects. The reference IEP of our samples is between 4 and 4.5. High temperature treatment tends to decrease the IEP of sapphire-c as does UV treatment. Increasing the initial miscut (i.e. the divergence from the expected orientation of the crystal) tends to increase the IEP as does plasma cleaning, which can be understood assuming that the surfaces have become less hydrophobic due to the presence of more and/or larger steps with increasing miscut or due to amorphisation of the surface caused by plasma cleaning. Pre-treatment at very high pH caused an increase in the IEP. Surface treatments that led to IEPs different from the stable value of reference samples typically resulted in surfaces that were strongly affected by subsequent exposure to water. The streaming potential data appear to relax to the reference sample behavior after a period of time of water exposure. Combination of the zeta-potential measurements with AFM investigations support the idea that atomically smooth surfaces exhibit lower IEPs, while rougher surfaces (roughness on the order of nanometers) result in higher IEPs compared to reference samples. Two supplementary investigations resulted in either surprising or ambiguous results. On very rough surfaces (roughness on the order of micrometers) the IEP lowered compared to the reference sample with nanometer-scale roughness and transient behavior of the rough surfaces was observed. Furthermore, differences in the IEP as obtained from streaming potential and static colloid adhesion measurements may suggest that hydrodynamics play a role in streaming potential experiments. We finally relate surface diffraction data from previous studies to possible interpretations of our electrokinetic data to corroborate the presence of a water film that can explain the low IEP. Calculations show that the surface diffraction data are in line with the presence of a water film, however, they do not allow to unambiguously resolve critical features of this film which might explain the observed surface chemical characteristics like the dangling OH-bond reported in sum frequency generation studies. A broad literature review on properties of related surfaces shows that the presence of such water films could in many cases affect the interfacial properties. Persistence or not of the water film can be crucial. The presence of the water film can in principle affect important processes like ice-nucleation, wetting behavior, electric charging, etc.
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16
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The pH dependent surface charging and points of zero charge. VII. Update. Adv Colloid Interface Sci 2018; 251:115-138. [PMID: 29153243 DOI: 10.1016/j.cis.2017.10.005] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 10/25/2017] [Accepted: 10/25/2017] [Indexed: 02/06/2023]
Abstract
The pristine points of zero charge (PZC) and isoelectric points (IEP) of metal oxides and IEP of other materials from the recent literature, and a few older results (overlooked in previous searches) are summarized. This study is an update of the previous compilations by the same author [Surface Charging and Points of Zero Charge, CRC, Boca Raton, 2009; J. Colloid Interface Sci. 337 (2009) 439; 353 (2011) 1; 426 (2014) 209]. The field has been very active, but most PZC and IEP are reported for materials, which are very well-documented already (silica, alumina, titania, iron oxides). IEP of (nominally) Gd2O3, NaTaO3, and SrTiO3 have been reported in the recent literature. Their IEP were not reported in older studies.
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17
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Kumar N, Andersson MP, van den Ende D, Mugele F, Siretanu I. Probing the Surface Charge on the Basal Planes of Kaolinite Particles with High-Resolution Atomic Force Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:14226-14237. [PMID: 29140711 PMCID: PMC5738629 DOI: 10.1021/acs.langmuir.7b03153] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
High-resolution atomic force microscopy is used to map the surface charge on the basal planes of kaolinite nanoparticles in an ambient solution of variable pH and NaCl or CaCl2 concentration. Using DLVO theory with charge regulation, we determine from the measured force-distance curves the surface charge distribution on both the silica-like and the gibbsite-like basal plane of the kaolinite particles. We observe that both basal planes do carry charge that varies with pH and salt concentration. The silica facet was found to be negatively charged at pH 4 and above, whereas the gibbsite facet is positively charged at pH below 7 and negatively charged at pH above 7. Investigations in CaCl2 at pH 6 show that the surface charge on the gibbsite facet increases for concentration up to 10 mM CaCl2 and starts to decrease upon further increasing the salt concentration to 50 mM. The increase of surface charge at low concentration is explained by Ca2+ ion adsorption, while Cl- adsorption at higher CaCl2 concentrations partially neutralizes the surface charge. Atomic resolution imaging and density functional theory calculations corroborate these observations. They show that hydrated Ca2+ ions can spontaneously adsorb on the gibbsite facet of the kaolinite particle and form ordered surface structures, while at higher concentrations Cl- ions will co-adsorb, thereby changing the observed ordered surface structure.
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Affiliation(s)
- N. Kumar
- Physics
of Complex Fluids Group, MESA+ Institute for Nanotechnology, University of Twente,
P. O. Box 217, 7500 AE Enschede, The Netherlands
| | - M. P. Andersson
- Nano-Science
Center, Department of Chemistry, University
of Copenhagen, Universitetsparken
5, 2100 Copenhagen, Denmark
| | - D. van den Ende
- Physics
of Complex Fluids Group, MESA+ Institute for Nanotechnology, University of Twente,
P. O. Box 217, 7500 AE Enschede, The Netherlands
| | - F. Mugele
- Physics
of Complex Fluids Group, MESA+ Institute for Nanotechnology, University of Twente,
P. O. Box 217, 7500 AE Enschede, The Netherlands
| | - I. Siretanu
- Physics
of Complex Fluids Group, MESA+ Institute for Nanotechnology, University of Twente,
P. O. Box 217, 7500 AE Enschede, The Netherlands
- E-mail:
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