1
|
Selloni A. Aqueous Titania Interfaces. Annu Rev Phys Chem 2024; 75:47-65. [PMID: 38271659 DOI: 10.1146/annurev-physchem-090722-015957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Water-metal oxide interfaces are central to many phenomena and applications, ranging from material corrosion and dissolution to photoelectrochemistry and bioengineering. In particular, the discovery of photocatalytic water splitting on TiO2 has motivated intensive studies of water-TiO2 interfaces for decades. So far, a broad understanding of the interaction of water vapor with several TiO2 surfaces has been obtained. However, much less is known about liquid water-TiO2 interfaces, which are more relevant to many practical applications. Probing these complex systems at the molecular level is experimentally challenging and is sometimes possible only through computational studies. This review summarizes recent advances in the atomistic understanding, mostly through computational simulations, of the structure and dynamics of interfacial water on TiO2 surfaces. The main focus is on the nature, molecular or dissociated, of water in direct contact with low-index defect-free crystalline surfaces. The hydroxyls resulting from water dissociation are essential in the photooxidation of water and critically affect the surface chemistry of TiO2.
Collapse
Affiliation(s)
- Annabella Selloni
- Department of Chemistry, Princeton University, Princeton, New Jersey, USA;
| |
Collapse
|
2
|
Lätsch L, Guda SA, Romankov V, Wartmann C, Neudörfl JM, Dreiser J, Berkessel A, Guda AA, Copéret C. Tracking Coordination Environment and Reaction Intermediates in Homogeneous and Heterogeneous Epoxidation Catalysts via Ti L 2,3-Edge Near-Edge X-ray Absorption Fine Structures. J Am Chem Soc 2024; 146:7456-7466. [PMID: 38447178 DOI: 10.1021/jacs.3c12831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Ti-based molecules and materials are ubiquitous and play a major role in both homogeneous and heterogeneous catalytic processes. Understanding the electronic structures of their active sites (oxidation state, local symmetry, and ligand environment) is key to developing molecular-level structure-property relationships. In that context, X-ray absorption spectroscopy (XAS) offers a unique combination of elemental selectivity and sensitivity to local symmetry. Commonly, for early transition metals such as Ti, K-edge XAS is applied for in situ characterization and subsequent structural analysis with high sensitivity toward tetrahedral species. Ti L2,3-edge spectroscopy is in principle complementary and offers specific opportunities to interrogate the electronic structure of five-and six-coordinated species. It is, however, much more rarely implemented because the use of soft X-rays implies ultrahigh vacuum conditions. Furthermore, the interpretation of the data can be challenging. Here, we show how Ti L2,3-edge spectroscopy can help to obtain unique information about both homogeneous and heterogeneous epoxidation catalysts and develop a molecular-level relationship between spectroscopic signatures and electronic structures. Toward this goal, we first establish a spectral library of molecular Ti reference compounds, comprising various coordination environments with mono- and dimeric Ti species having O, N, and Cl ligands. We next implemented a computational methodology based on multiplet ligand field theory and maximally localized Wannier orbitals benchmarked on our library to understand Ti L2,3-edge spectroscopic signatures. We finally used this approach to track and predict the spectra of catalytically relevant intermediates, focusing on Ti-based olefin epoxidation catalysts.
Collapse
Affiliation(s)
- Lukas Lätsch
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog Weg 2, CH 8093Zurich, Switzerland
| | - Sergey A Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178324, 344090Rostov-on-Don, Russia
| | - Vladyslav Romankov
- Swiss Light Source, Paul Scherrer Institut, CH-5232Villigen, Switzerland
| | - Christina Wartmann
- Department of Chemistry, Organic Chemistry, University of Cologne, Greinstraße 4, 50939 Cologne, Germany
| | - Jörg-M Neudörfl
- Department of Chemistry, Organic Chemistry, University of Cologne, Greinstraße 4, 50939 Cologne, Germany
| | - Jan Dreiser
- Swiss Light Source, Paul Scherrer Institut, CH-5232Villigen, Switzerland
| | - Albrecht Berkessel
- Department of Chemistry, Organic Chemistry, University of Cologne, Greinstraße 4, 50939 Cologne, Germany
| | - Alexander A Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178324, 344090Rostov-on-Don, Russia
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog Weg 2, CH 8093Zurich, Switzerland
| |
Collapse
|
3
|
Chang H, Lozier EH, Ma E, Geiger FM. Quantification of Stern Layer Water Molecules, Total Potentials, and Energy Densities at Fused Silica:Water Interfaces for Adsorbed Alkali Chlorides, CTAB, PFOA, and PFAS. J Phys Chem A 2023; 127:8404-8414. [PMID: 37775181 DOI: 10.1021/acs.jpca.3c04434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2023]
Abstract
We have employed amplitude- and phase-resolved second-harmonic generation spectroscopy to investigate ion-specific effects of monovalent cations at the fused silica:water interface maintained under acidic, neutral, and alkaline conditions. We find a negligible dependence of the total potential (as negative as -400 mV at pH 14), the second-order nonlinear susceptibility (as large as 1.5 × 10-21 m2 V-1 at pH 14), the number of Stern layer water molecules (1 × 1015 cm-2 at pH 5.8), and the energy associated with water alignment upon going from neutral to high pH (ca. -24 kJ mol-1 to -48 kJ mol-1 at pH 13 and 14, close to the cohesive energy of liquid water but smaller than that of ice) on chlorides of the alkali series (M+ = Li+, Na+, K+, Rb+, and Cs+). Attempts are presented to provide estimates for the molecular hyperpolarizability of the cations and anions in the Stern layer at high pH, which arrive at ca. 20-fold larger values for αtotal ions(2) = αM+(2) + αOH-(2) + αCl-(2) when compared to water's molecular hyperpolarizability estimate from theory and point to a sizable contribution of deprotonated silanol groups at high pH. In contrast to the alkali series, a pronounced dependence of the total potential and the second-order nonlinear susceptibility on monovalent cationic (cetrimonium bromide, CTAB) and anionic (perfluorooctanoic and perfluorooctanesulfonic acid, PFOA and PFOS) surfactants was quantifiable. Our findings are consistent with a low surface coverage of the alkali cations and a high surface coverage of the surfactants. Moreover, they underscore the important contribution of Stern layer water molecules to the total potential and second-order nonlinear susceptibility. Finally, they demonstrate the applicability of heterodyne-detected second-harmonic generation spectroscopy for identifying perfluorinated acids at mineral:water interfaces.
Collapse
Affiliation(s)
- HanByul Chang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Emilie H Lozier
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Emily Ma
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Franz M Geiger
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| |
Collapse
|
4
|
Petit T, Lounasvuori M, Chemin A, Bärmann P. Nanointerfaces: Concepts and Strategies for Optical and X-ray Spectroscopic Characterization. ACS PHYSICAL CHEMISTRY AU 2023; 3:263-278. [PMID: 37249937 PMCID: PMC10214513 DOI: 10.1021/acsphyschemau.2c00058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/25/2023] [Accepted: 01/25/2023] [Indexed: 05/31/2023]
Abstract
Interfaces at the nanoscale, also called nanointerfaces, play a fundamental role in physics and chemistry. Probing the chemical and electronic environment at nanointerfaces is essential in order to elucidate chemical processes relevant for applications in a variety of fields. Many spectroscopic techniques have been applied for this purpose, although some approaches are more appropriate than others depending on the type of the nanointerface and the physical properties of the different phases. In this Perspective, we introduce the major concepts to be considered when characterizing nanointerfaces. In particular, the interplay between the characteristic length of the nanointerfaces, and the probing and information depths of different spectroscopy techniques is discussed. Differences between nano- and bulk interfaces are explained and illustrated with chosen examples from optical and X-ray spectroscopies, focusing on solid-liquid nanointerfaces. We hope that this Perspective will help to prepare spectroscopic characterization of nanointerfaces and stimulate interest in the development of new spectroscopic techniques adapted to the nanointerfaces.
Collapse
|
5
|
Cho DY, Kim KJ, Lee KS, Lübben M, Chen S, Valov I. Chemical Influence of Carbon Interface Layers in Metal/Oxide Resistive Switches. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18528-18536. [PMID: 36989142 PMCID: PMC10103050 DOI: 10.1021/acsami.3c00920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Thin layers introduced between a metal electrode and a solid electrolyte can significantly alter the transport of mass and charge at the interfaces and influence the rate of electrode reactions. C films embedded in functional materials can change the chemical properties of the host, thereby altering the functionality of the whole device. Using X-ray spectroscopies, here we demonstrate that the chemical and electronic structures in a representative redox-based resistive switching (RS) system, Ta2O5/Ta, can be tuned by inserting a graphene or ultrathin amorphous C layer. The results of the orbitalwise analyses of synchrotron Ta L3-edge, C K-edge, and O K-edge X-ray absorption spectroscopy showed that the C layers between Ta2O5 and Ta are significantly oxidized to form COx and, at the same time, oxidize the Ta layers with different degrees of oxidation depending on the distance: full oxidation at the nearest 5 nm Ta and partial oxidation in the next 15 nm Ta. The depth-resolved information on the electronic structure for each layer further revealed a significant modification of the band alignments due to C insertion. Full oxidation of the Ta metal near the C interlayer suggests that the oxygen-vacancy-related valence change memory mechanism for the RS can be suppressed, thereby changing the RS functionalities fundamentally. The knowledge on the origin of C-enhanced surfaces can be applied to other metal/oxide interfaces and used for the advanced design of memristive devices.
Collapse
Affiliation(s)
- Deok-Yong Cho
- IPIT
and Department of Physics, Jeonbuk National
University, Jeonju 54896, Republic of Korea
| | - Ki-jeong Kim
- Pohang
Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Kug-Seung Lee
- Pohang
Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Michael Lübben
- Peter
Gruenberg
Institute, Research Centre Juelich, Juelich 52425, Germany
| | - Shaochuan Chen
- IWE2, RWTH Aachen University, Sommerfed strasse 24, Aachen 52074, Germany
| | - Ilia Valov
- Peter
Gruenberg
Institute, Research Centre Juelich, Juelich 52425, Germany
- Institute
of Electrochemistry and Energy Systems “acad. E. Budewski”, Bulgarian Academy of Sciences, “acad. G Bonchev” street Bl.10, Sofia 1113, Bulgaria
| |
Collapse
|
6
|
Śliz A, Radecka M, Jeleń P, Dorosz D, Zakrzewska K. Near-infrared to visible and ultraviolet upconversion in TiO 2 thin films modified with Er and Yb. RSC Adv 2023; 13:7402-7412. [PMID: 36895765 PMCID: PMC9990154 DOI: 10.1039/d2ra08305a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 02/26/2023] [Indexed: 03/09/2023] Open
Abstract
Upconversion as a modification strategy to enhance the utilization of sunlight in titanium dioxide photoanodes with an internal upconverter was investigated. TiO2 thin films containing an Er activator and Yb sensitizer were deposited in the magnetron sputtering process on conducting glass, amorphous silica, and silicon. Scanning electron microscopy, energy dispersive spectroscopy, grazing incidence X-ray diffraction, and X-ray absorption spectroscopy allowed assessment of the thin film composition, structure, and microstructure. Optical and photoluminescence properties were measured by means of spectrophotometry and spectrofluorometry. Changing the content of Er3+ (1, 2, 10 at%) and Yb3+ (1, 10 at%) ions allowed us to achieve thin film upconverters with a crystallized and amorphous host. Upon 980 nm laser excitation Er3+ exhibits upconversion with the main emission in green (2H11/2 → 4I15/2, λ em ≈ 525 nm) and weak emission in red (4F9/2 → 4I15/2, λ em ≈ 660 nm). For a thin film with a higher ytterbium content (10 at%) a significant increase in red emission and upconversion from NIR to UV was observed. The average decay times of green emission for TiO2:Er and TiO2:Er,Yb thin films were calculated based on time-resolved emission measurements.
Collapse
Affiliation(s)
- Anna Śliz
- Faculty of Materials Science and Ceramics, AGH University of Science and Technology al. A. Mickiewicza 30 30-059 Kraków Poland
| | - Marta Radecka
- Faculty of Materials Science and Ceramics, AGH University of Science and Technology al. A. Mickiewicza 30 30-059 Kraków Poland
| | - Piotr Jeleń
- Faculty of Materials Science and Ceramics, AGH University of Science and Technology al. A. Mickiewicza 30 30-059 Kraków Poland
| | - Dominik Dorosz
- Faculty of Materials Science and Ceramics, AGH University of Science and Technology al. A. Mickiewicza 30 30-059 Kraków Poland
| | - Katarzyna Zakrzewska
- Faculty of Computer Science, Electronics and Telecommunications, AGH University of Science and Technology al. A. Mickiewicza 30 30-059 Kraków Poland
| |
Collapse
|
7
|
Jäker P, Aegerter D, Kyburz T, Städler R, Fonjallaz R, Detlefs B, Koziej D. Flow cell for operando X-ray photon-in-photon-out studies on photo-electrochemical thin film devices. OPEN RESEARCH EUROPE 2022; 2:74. [PMID: 37645301 PMCID: PMC10446061 DOI: 10.12688/openreseurope.14433.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/01/2022] [Indexed: 08/31/2023]
Abstract
Background: Photo-electro-chemical (PEC) water splitting represents a promising technology towards an artificial photosynthetic device but many fundamental electronic processes, which govern long-term stability and energetics, are not yet fully understood. X-ray absorption spectroscopy (XAS), and particularly its high energy resolution fluorescence-detected (HERFD) mode, emerges as a powerful tool to study photo-excited charge carrier behavior under operating conditions. The established thin film device architecture of PEC cells provides a well-defined measurement geometry, but it puts many constraints on conducting operando XAS experiments. It remains a challenge to establish a standardized thin film exchange procedure and concurrently record high-quality photoelectrochemical and X‑ray absorption spectroscopy data that is unperturbed by bubble formation. Here we address and overcome these instrumental limitations for photoelectrochemical operando HERFD-XAS. Methods: We constructed a novel operando photo-electro-chemical cell by computer numerical control milling, guided by the materials' X‑ray and visible light absorption properties to optimize signal detection. To test the cell's functionality, semiconducting thin film photoelectrodes have been fabricated via solution deposition and their photoelectrochemical responses under simulated solar light were studied using a commercial potentiostat in a three-electrode configuration during HERFD-XAS experiments at a synchrotron. Results: We demonstrate the cell's capabilities to measure and control potentiostatically and in open‑circuit, to detect X‑ray signals unperturbed by bubbles and to fluently exchange different thin film samples by collecting high-resolution Fe K-edge spectra of hematite ( α -Fe 2O 3) and ferrite thin film ( MFe 2O 4, M= Zn, Ni) photoelectrodes during water oxidation. Conclusions: Our cell establishes a measurement routine that will provide experimental access of photo-electro-chemical operando HERFD-XAS experiments to a broader scientific community, particularly due to the ease of sample exchange. We believe to enable a broad range of experiments which acquired fundamental insights will spur further photoelectrochemical research and commercialization of water splitting technologies.
Collapse
Affiliation(s)
- Philipp Jäker
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
- Institutes of Nanostructure and Solid State Physics, Center for Hybrid Nanostructures, University of Hamburg, Hamburg, Luruper Chaussee 149, 22607, Germany
| | - Dino Aegerter
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
| | - Till Kyburz
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
| | - Roman Städler
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
| | - Rea Fonjallaz
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
| | - Blanka Detlefs
- European Synchrotron Radiation Facility, Grenoble, 71 avenue des Martyrs, CS 40220, 38043, France
| | - Dorota Koziej
- Department of Materials, Laboratory for Multifunctional Materials, ETH Zürich, Zurich, Vladimir-Prelog-Weg 5, 8093, Switzerland
- Institutes of Nanostructure and Solid State Physics, Center for Hybrid Nanostructures, University of Hamburg, Hamburg, Luruper Chaussee 149, 22607, Germany
| |
Collapse
|
8
|
Revealing solid electrolyte interphase formation through interface-sensitive Operando X-ray absorption spectroscopy. Nat Commun 2022; 13:6070. [PMID: 36241622 PMCID: PMC9568580 DOI: 10.1038/s41467-022-33691-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 09/28/2022] [Indexed: 11/12/2022] Open
Abstract
The solid electrolyte interphase (SEI) that forms on Li-ion battery anodes is critical to their long-term performance, however observing SEI formation processes at the buried electrode-electrolyte interface is a significant challenge. Here we show that operando soft X-ray absorption spectroscopy in total electron yield mode can resolve the chemical evolution of the SEI during electrochemical formation in a Li-ion cell, with nm-scale interface sensitivity. O, F, and Si K-edge spectra, acquired as a function of potential, reveal when key reactions occur on high-capacity amorphous Si anodes cycled with and without fluoroethylene carbonate (FEC). The sequential formation of inorganic (LiF) and organic (-(C=O)O-) components is thereby revealed, and results in layering of the SEI. The addition of FEC leads to SEI formation at higher potentials which is implicated in the rapid healing of SEI defects and the improved cycling performance observed. Operando TEY-XAS offers new insights into the formation mechanisms of electrode-electrolyte interphases and their stability for a wide variety of electrode materials and electrolyte formulations. Solid electrolyte interphase (SEI) formation on Li-ion battery anodes is critical for long-term performance. Here, the authors use operando soft X-ray absorption spectroscopy in total electron yield mode to resolve the chemical evolution of the SEI during electrochemical formation on silicon anodes.
Collapse
|
9
|
Yang Y, Roh I, Louisia S, Chen C, Jin J, Yu S, Salmeron MB, Wang C, Yang P. Operando Resonant Soft X-ray Scattering Studies of Chemical Environment and Interparticle Dynamics of Cu Nanocatalysts for CO 2 Electroreduction. J Am Chem Soc 2022; 144:8927-8931. [PMID: 35575474 DOI: 10.1021/jacs.2c03662] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the chemical environment and interparticle dynamics of nanoparticle electrocatalysts under operating conditions offers valuable insights into tuning their activity and selectivity. This is particularly important to the design of Cu nanocatalysts for CO2 electroreduction due to their dynamic nature under bias. Here, we have developed operando electrochemical resonant soft X-ray scattering (EC-RSoXS) to probe the chemical identity of active sites during the dynamic structural transformation of Cu nanoparticle (NP) ensembles through 1 μm thick electrolyte. Operando scattering-enhanced X-ray absorption spectroscopy (XAS) serves as a powerful technique to investigate the size-dependent catalyst stability under beam exposure while monitoring the potential-dependent surface structural changes. Small NPs (7 nm) in aqueous electrolyte were found to experience a predominant soft X-ray beam-induced oxidation to CuO despite only sub-second X-ray exposure. In comparison, large NPs (18 nm) showed improved resistivity to beam damage, which allowed the reliable observation of surface Cu2O electroreduction to metallic Cu. Small-angle X-ray scattering (SAXS) statistically probes the particle-particle interactions of large ensembles of NPs. This study points out the need for rigorous examination of beam effects for operando X-ray studies on electrocatalysts. The strategy of using EC-RSoXS that combines soft XAS and SAXS can serve as a general approach to simultaneously investigate the chemical environment and interparticle information on nanocatalysts.
Collapse
Affiliation(s)
- Yao Yang
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Miller Institute for Basic Research in Science, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Inwhan Roh
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Sheena Louisia
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Chubai Chen
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jianbo Jin
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Sunmoon Yu
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
| | - Miquel B Salmeron
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Cheng Wang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Peidong Yang
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Kavli Energy NanoScience Institute, Berkeley, California 94720, United States
| |
Collapse
|