1
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Jensen S, Mammen MHR, Hedevang M, Li Z, Lammich L, Lauritsen JV. Visualizing the gas-sensitive structure of the CuZn surface in methanol synthesis catalysis. Nat Commun 2024; 15:3865. [PMID: 38719827 PMCID: PMC11079032 DOI: 10.1038/s41467-024-48168-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 04/23/2024] [Indexed: 05/12/2024] Open
Abstract
Methanol formation over Cu/ZnO catalysts is linked with a catalytically active phase created by contact between Cu nanoparticles and Zn species whose chemical and structural state depends on reaction conditions. Herein, we use variable-temperature scanning tunneling microscopy at elevated pressure conditions combined with X-ray photoelectron spectroscopy measurements to investigate the surface structures and chemical states that evolve when a CuZn/Cu(111) surface alloy is exposed to reaction gas mixtures. In CO2 hydrogenation conditions, Zn stays embedded in the CuZn surface, but once CO gas is added to the mixture, the Zn segregates onto the Cu surface. The Zn segregation is CO-induced, and establishes a new dynamic state of the catalyst surface where Zn is continually exchanged at the Cu surface. Candidates for the migrating few-atom Zn clusters are further identified in time-resolved imaging series. The findings point to a significant role of CO affecting the distribution of Zn in the multiphasic ZnO/CuZn/Cu catalysts.
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Affiliation(s)
- Sigmund Jensen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus C, Denmark
| | - Mathias H R Mammen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus C, Denmark
| | - Martin Hedevang
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus C, Denmark
| | - Zheshen Li
- Department of Physics and Astronomy, Aarhus University, 8000, Aarhus C, Denmark
| | - Lutz Lammich
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus C, Denmark
- Department of Physics and Astronomy, Aarhus University, 8000, Aarhus C, Denmark
| | - Jeppe V Lauritsen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus C, Denmark.
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2
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Liu C, Lin L, Wu H, Liu Y, Mu R, Fu Q. Activating lattice oxygen of single-layer ZnO for the catalytic oxidation reaction. Phys Chem Chem Phys 2023; 25:20121-20127. [PMID: 37462941 DOI: 10.1039/d3cp02580b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Tuning an oxide/metal interface is of critical importance for the performance enhancement of many heterogeneous catalytic reactions. However, catalytic oxidation occurring at the interface between non-reducible oxide and metal has been challenging, since non-reducible oxides hardly lose their lattice oxygen (OL) or dissociate O2 from the gas phase. In this work, a ZnO monolayer film on Au(111) is used as an inverse catalyst to investigate CO oxidation occurring at the ZnO/Au(111) interface via high pressure scanning tunneling microscopy. Surface science experiments indicate that oxygen intercalation under the ZnO monolayer film, termed ZnO/O/Au(111), can be achieved via a surface reaction with 1 × 10-6 mbar O3. Subsequent exposure of the formed ZnO/O/Au(111) surface to mbar CO at room temperature leads to the recovery of the pristine ZnO/Au(111) surface. Theoretical calculations reveal that OL adjacent to intercalated oxygen (Oint) is activated due to the OL-Zn-Oint bonding and surface corrugation, which can be directly involved in CO oxidation. Subsequently, Oint migrates to the formed oxygen vacancy from the subsurface resuming the pristine ZnO structure. These results thus reveal that oxygen intercalation underneath single-layer ZnO will strongly boost the oxidation reaction via activating adjacent lattice oxygen atoms.
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Affiliation(s)
- Changping Liu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Le Lin
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Hao Wu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Yijing Liu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rentao Mu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Qiang Fu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
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3
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Sawant KJ, Zeng Z, Greeley JP. Universal properties of metal-supported oxide films from linear scaling relationships: elucidation of mechanistic origins of strong metal–support interactions. Chem Sci 2023; 14:3206-3214. [PMID: 36970101 PMCID: PMC10034000 DOI: 10.1039/d2sc06656d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/31/2023] [Indexed: 02/09/2023] Open
Abstract
General principles of Strong Metal–Support Interactions (SMSI) overlayer formation have been elucidated using predictive models derived from ultrathin (hydroxy)oxide films on transition metal substrates.
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Affiliation(s)
- Kaustubh J. Sawant
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, IN 47907, USA
| | - Zhenhua Zeng
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, IN 47907, USA
| | - Jeffrey P. Greeley
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, IN 47907, USA
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4
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Shen Y, Yuan Z, Cui Z, Ma D, Yang K, Dong Y, Wang F, Du A, Li E. Electronic, Magnetic, and Optical Properties of Metal Adsorbed g-ZnO Systems. Front Chem 2022; 10:943902. [PMID: 35844655 PMCID: PMC9282636 DOI: 10.3389/fchem.2022.943902] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 06/03/2022] [Indexed: 11/13/2022] Open
Abstract
2D ZnO is one of the most attractive materials for potential applications in photocatalysis, gas and light detection, ultraviolet light-emitting diodes, resistive memory, and pressure-sensitive devices. The electronic structures, magnetic properties, and optical properties of M (Li, Na, Mg, Ca, or Ga) and TM (Cr, Co, Cu, Ag, or Au) adsorbed g-ZnO were investigated with density functional theory (DFT). It is found that the band structure, charge density difference, electron spin density, work function, and absorption spectrum of g-ZnO can be tuned by adsorbing M or TM atoms. More specifically, the specific charge transfer occurs between g-ZnO and adsorbed atom, indicating the formation of a covalent bond. The work functions of M adsorbed g-ZnO systems are obviously smaller than that of intrinsic g-ZnO, implying great potential in high-efficiency field emission devices. The Li, Na, Mg, Ca, Ga, Ag, or Au adsorbed g-ZnO systems, the Cr adsorbed g-ZnO system, and the Co or Cu adsorbed g-ZnO systems exhibit non-magnetic semiconductor proprieties, magnetic semiconductor proprieties, and magnetic metal proprieties, respectively. In addition, the magnetic moments of Cr, Co, or Cu adsorbed g-ZnO systems are 4 μB, 3 μB, or 1 μB, respectively, which are mainly derived from adsorbed atoms, suggesting potential applications in nano-scale spintronics devices. Compared with the TM absorbed g-ZnO systems, the M adsorbed g-ZnO systems have more obvious absorption peaks for visible light, particularly for Mg or Ca adsorbed g-ZnO systems. Their absorption peaks appear in the near-infrared region, suggesting great potential in solar photocatalysis. Our work contributes to the design and fabrication of high-efficiency field emission devices, nano-scale spintronics devices, and visible-light responsive photocatalytic materials.
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Affiliation(s)
- Yang Shen
- School of Science, Xi’an University of Technology, Xi’an, China
- *Correspondence: Yang Shen, ; Zhen Cui, ; Enling Li,
| | - Zhihao Yuan
- School of Science, Xi’an University of Technology, Xi’an, China
| | - Zhen Cui
- School of Automation and Information Engineering, Xi’an University of Technology, Xi’an, China
- *Correspondence: Yang Shen, ; Zhen Cui, ; Enling Li,
| | - Deming Ma
- School of Science, Xi’an University of Technology, Xi’an, China
| | - Kunqi Yang
- School of Science, Xi’an University of Technology, Xi’an, China
| | - Yanbo Dong
- School of Science, Xi’an University of Technology, Xi’an, China
| | - Fangping Wang
- School of Science, Xi’an University of Technology, Xi’an, China
| | - Ai Du
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai, China
| | - Enling Li
- School of Science, Xi’an University of Technology, Xi’an, China
- *Correspondence: Yang Shen, ; Zhen Cui, ; Enling Li,
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5
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Liu S, Wolf M, Kumagai T. Nanoscale Heating of an Ultrathin Oxide Film Studied by Tip-Enhanced Raman Spectroscopy. PHYSICAL REVIEW LETTERS 2022; 128:206803. [PMID: 35657872 DOI: 10.1103/physrevlett.128.206803] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/13/2022] [Accepted: 04/11/2022] [Indexed: 06/15/2023]
Abstract
We report on the nanoscale heating mechanism of an ultrathin ZnO film using low-temperature tip-enhanced Raman spectroscopy. Under the resonance condition, intense Stokes and anti-Stokes Raman scattering can be observed for the phonon modes of a two-monolayer (ML) ZnO on an Ag(111) surface, enabling us to monitor local heating at the nanoscale. It is revealed that the local heating originates mainly from inelastic electron tunneling through the electronic resonance when the bias voltage exceeds the conduction band edge of the 2-ML ZnO. When the bias voltage is lower than the conduction band edge, the local heating arises from two different contributions, namely direct optical excitation between the interface state and the conduction band of 2-ML ZnO or injection of photoexcited electrons from an Ag tip into the conduction band. These optical heating processes are promoted by localized surface plasmon excitation. Simultaneous mapping of tip-enhanced Raman spectroscopy and scanning tunneling spectroscopy for 2-ML ZnO including an atomic-scale defect demonstrates visualizing a correlation between the heating efficiency and the local density of states, which further allows us to analyze the local electron-phonon coupling strength with ∼2 nm spatial resolution.
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Affiliation(s)
- Shuyi Liu
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Martin Wolf
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Takashi Kumagai
- Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
- Center for Mesoscopic Sciences, Institute for Molecular Science, Okazaki 444-8585, Japan
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6
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Schlögl R. Chemische Batterien mit CO
2. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202007397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Robert Schlögl
- Max-Planck-Institut für Chemische Energiekonversion Stiftstraße 34–36 45470 Mülheim an der Ruhr Deutschland
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4–6 14195 Berlin Deutschland
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7
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Saedy S, Newton MA, Zabilskiy M, Lee JH, Krumeich F, Ranocchiari M, van Bokhoven JA. Copper–zinc oxide interface as a methanol-selective structure in Cu–ZnO catalyst during catalytic hydrogenation of carbon dioxide to methanol. Catal Sci Technol 2022. [DOI: 10.1039/d2cy00224h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The proper contact of zinc oxide and copper phases is essential achieving high activity/selectivity toward methanol in the Cu–ZnO system.
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Affiliation(s)
- Saeed Saedy
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Mark A. Newton
- Institute for Chemistry and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland
| | - Maxim Zabilskiy
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Jin Hee Lee
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Frank Krumeich
- Laboratory of Inorganic Chemistry, Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zurich, Switzerland
| | - Marco Ranocchiari
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Jeroen A. van Bokhoven
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
- Institute for Chemistry and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland
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8
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Electronic and optical properties of two-dimensional GaN/ZnO heterojunction tuned by different stacking configurations. J Colloid Interface Sci 2021; 607:913-921. [PMID: 34571312 DOI: 10.1016/j.jcis.2021.09.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 09/09/2021] [Accepted: 09/09/2021] [Indexed: 11/21/2022]
Abstract
Two-dimensional (2D) semiconductors show novel electronic and optoelectronic applications due to their excellent performance. The van der Waals (vdW) heterostructures are also a new method for the design of low dimensional optoelectronic devices. However, their fundamental electronic structure and optical properties are sensitive to stacking configurations. Herein, we perform systematic first-principle calculations for monolayer GaN and ZnO by six different stacking styles. The results suggest that the bonding type and stability vary with the stacking method. Chemical bonding and vdW interaction are respectively observed in different models. However, the carrier mobilities for different models are all enhanced after integration. Both type I and II band alignment can be generated from different stacking models. The optical properties suggest high absorptivity in the solar-blind region. This study is an early stage for the design and synthesis of photodetectors or solar cells based on 2D GaN/ZnO heterojunctions and also opens a far-ranging research interest in optoelectronic materials and devices with more advanced semiconductor materials.
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9
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Gao J, Sawant KJ, Miller JT, Zeng Z, Zemlyanov D, Greeley JP. Structural and Chemical Transformations of Zinc Oxide Ultrathin Films on Pd(111) Surfaces. ACS APPLIED MATERIALS & INTERFACES 2021; 13:35113-35123. [PMID: 34275280 DOI: 10.1021/acsami.1c07510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Structural and chemical transformations of ultrathin oxide films on transition metals lie at the heart of many complex phenomena in heterogeneous catalysis, such as the strong metal-support interaction (SMSI). However, there is limited atomic-scale understanding of these transformations, especially for irreducible oxides such as ZnO. Here, by combining density functional theory calculations and surface science techniques, including scanning tunneling microscopy, X-ray photoelectron spectroscopy, high-resolution electron energy loss spectroscopy, and low-energy electron diffraction, we investigated the interfacial interaction of well-defined ultrathin ZnOxHy films on Pd(111) under varying gas-phase conditions [ultrahigh vacuum (UHV), 5 × 10-7 mbar of O2, and a D2/O2 mixture] to shed light on the SMSI effect of irreducible oxides. Sequential treatment of submonolayer zinc oxide films in a D2/O2 mixture (1:4) at 550 K evoked reversible structural transformations from a bilayer to a monolayer and further to a Pd-Zn near-surface alloy, demonstrating that zinc oxide, as an irreducible oxide, can spread on metal surfaces and show an SMSI-like behavior in the presence of hydrogen. A mixed canonical-grand canonical phase diagram was developed to bridge the gap between UHV conditions and true SMSI environments, revealing that, in addition to surface alloy formation, certain ZnOxHy films with stoichiometries that do not exist in bulk are stabilized by Pd in the presence of hydrogen. Based on the combined theoretical and experimental observations, we propose that SMSI metal nanoparticle encapsulation for irreducible oxide supports such as ZnO involves both surface (hydroxy)oxide and surface alloy formation, depending on the environmental conditions.
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Affiliation(s)
- Junxian Gao
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47906, United States
| | - Kaustubh J Sawant
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47906, United States
| | - Jeffrey T Miller
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47906, United States
| | - Zhenhua Zeng
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47906, United States
| | - Dmitry Zemlyanov
- Birck Nanotechnology Center, Purdue University, 1205 W State Street, West Lafayette, Indiana 47907, United States
| | - Jeffrey P Greeley
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47906, United States
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10
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Romero M, Mombrú D, Pignanelli F, Faccio R, Mombrú ÁW. From Chain- to Graphene-like Hydroxyl-terminated (ZnO) n Clusters with n≤6 Obtained via Zinc Dimethoxide Hydrolysis and Condensation: Ab initio Structural, Electronic, Vibrational and Optical Properties Calculations. Chemphyschem 2021; 22:849-863. [PMID: 33646619 DOI: 10.1002/cphc.202100054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 03/01/2021] [Indexed: 11/08/2022]
Abstract
Recent reports are focusing on the structural evolution from the atomic-scale and also at the expenses of alkyl zinc alkoxide precursors towards (ZnO)n clusters and nanostructures with different interesting motifs, but still not much is known about their electronic properties. In this manuscript, we present a theoretical study using DFT and TD-DFT methodologies on the hydrolysis and condensation of zinc dimethoxide precursor in its monomeric, dimeric and trimeric forms towards thermodynamically stable hydroxyl-terminated (ZnO)n clusters with novel chain- and graphene-like fashions. For all cases, distinct vibrational and optical spectra features were assigned evidencing a global monotonic decrease in the opto-electronic gap with increasing oligomerization and cyclization stages. In addition, the electron-affinity of all clusters was also observed to be enhanced with increasing oligomerization and cyclization stages and the electronic charge localization in -e charged clusters was observed to be strongly related to the presence of zinc-oxo subunits and other particular structural features. Our calculations also indicate that the stabilization through hydroxyl termination of both chain- and graphene-like ZnO clusters not only could be a promising driving force to obtain larger atomic-scale 1D and 2D nanostructures but also envisage interesting properties, particularly as electronic acceptor materials for energy applications.
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Affiliation(s)
- Mariano Romero
- Centro NanoMat & Área Física, Departamento de Experimentación y Teoría de la Estructura de la Materia y sus Aplicaciones (DETEMA), Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Dominique Mombrú
- Centro NanoMat & Área Física, Departamento de Experimentación y Teoría de la Estructura de la Materia y sus Aplicaciones (DETEMA), Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Fernando Pignanelli
- Centro NanoMat & Área Física, Departamento de Experimentación y Teoría de la Estructura de la Materia y sus Aplicaciones (DETEMA), Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Ricardo Faccio
- Centro NanoMat & Área Física, Departamento de Experimentación y Teoría de la Estructura de la Materia y sus Aplicaciones (DETEMA), Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Álvaro W Mombrú
- Centro NanoMat & Área Física, Departamento de Experimentación y Teoría de la Estructura de la Materia y sus Aplicaciones (DETEMA), Facultad de Química, Universidad de la República, Montevideo, Uruguay
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11
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Zhang H, Holbrook M, Cheng F, Nam H, Liu M, Pan CR, West D, Zhang S, Chou MY, Shih CK. Epitaxial Growth of Two-Dimensional Insulator Monolayer Honeycomb BeO. ACS NANO 2021; 15:2497-2505. [PMID: 33481561 DOI: 10.1021/acsnano.0c06596] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The emergence of two-dimensional (2D) materials launched a fascinating frontier of flatland electronics. Most crystalline atomic layer materials are based on layered van der Waals materials with weak interlayer bonding, which naturally leads to thermodynamically stable monolayers. We report the synthesis of a 2D insulator composed of a single atomic sheet of honeycomb structure BeO (h-BeO), although its bulk counterpart has a wurtzite structure. The h-BeO is grown by molecular beam epitaxy (MBE) on Ag(111) thin films that are also epitaxially grown on Si(111) wafers. Using scanning tunneling microscopy and spectroscopy (STM/S), the honeycomb BeO lattice constant is determined to be 2.65 Å with an insulating band gap of 6 eV. Our low-energy electron diffraction measurements indicate that the h-BeO forms a continuous layer with good crystallinity at the millimeter scale. Moiré pattern analysis shows the BeO honeycomb structure maintains long-range phase coherence in atomic registry even across Ag steps. We find that the interaction between the h-BeO layer and the Ag(111) substrate is weak by using STS and complementary density functional theory calculations. We not only demonstrate the feasibility of growing h-BeO monolayers by MBE, but also illustrate that the large-scale growth, weak substrate interactions, and long-range crystallinity make h-BeO an attractive candidate for future technological applications. More significantly, the ability to create a stable single-crystalline atomic sheet without a bulk layered counterpart is an intriguing approach to tailoring 2D electronic materials.
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Affiliation(s)
- Hui Zhang
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Madisen Holbrook
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Fei Cheng
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Hyoungdo Nam
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Mengke Liu
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Chi-Ruei Pan
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Damien West
- Department of Physics, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Shengbai Zhang
- Department of Physics, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Mei-Yin Chou
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Chih-Kang Shih
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
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12
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Yu X, Roth JP, Wang J, Sauter E, Nefedov A, Heißler S, Pacchioni G, Wang Y, Wöll C. Chemical Reactivity of Supported ZnO Clusters: Undercoordinated Zinc and Oxygen Atoms as Active Sites. Chemphyschem 2020; 21:2553-2564. [PMID: 33118300 PMCID: PMC7756222 DOI: 10.1002/cphc.202000747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/21/2020] [Indexed: 11/06/2022]
Abstract
The growth of ZnO clusters supported by ZnO-bilayers on Ag(111) and the interaction of these oxide nanostructures with water have been studied by a multi-technique approach combining temperature-dependent infrared reflection absorption spectroscopy (IRRAS), grazing-emission X-ray photoelectron spectroscopy, and density functional theory calculations. Our results reveal that the ZnO bilayers exhibiting graphite-like structure are chemically inactive for water dissociation, whereas small ZnO clusters formed on top of these well-defined, yet chemically passive supports show extremely high reactivity - water is dissociated without an apparent activation barrier. Systematic isotopic substitution experiments using H2 16 O/D2 16 O/D2 18 O allow identification of various types of acidic hydroxyl groups. We demonstrate that a reliable characterization of these OH-species is possible via co-adsorption of CO, which leads to a red shift of the OD frequency due to the weak interaction via hydrogen bonding. The theoretical results provide atomic-level insight into the surface structure and chemical activity of the supported ZnO clusters and allow identification of the presence of under-coordinated Zn and O atoms at the edges and corners of the ZnO clusters as the active sites for H2 O dissociation.
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Affiliation(s)
- Xiaojuan Yu
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Jannik P. Roth
- Dipartimento di Scienza dei MaterialiUniversità Milano-BicoccaVia R. Cozzi 5520125MilanoItaly
| | - Junjun Wang
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Eric Sauter
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Alexei Nefedov
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Stefan Heißler
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei MaterialiUniversità Milano-BicoccaVia R. Cozzi 5520125MilanoItaly
| | - Yuemin Wang
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
| | - Christof Wöll
- Institute of Functional InterfacesKarlsruhe Institute of TechnologyEggenstein-Leopoldshafen76344Germany
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13
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Abstract
Efforts to obtain raw materials from CO2 by catalytic reduction as a means of combating greenhouse gas emissions are pushing the boundaries of the chemical industry. The dimensions of modern energy regimes, on the one hand, and the necessary transport and trade of globally produced renewable energy, on the other, will require the use of chemical batteries in conjunction with the local production of renewable electricity. The synthesis of methanol is an important option for chemical batteries and will, for that reason, be described here in detail. It is also shown that the necessary, robust, and fundamental understanding of processes and the material science of catalysts for the hydrogenation of CO2 does not yet exist.
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Affiliation(s)
- Robert Schlögl
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany.,Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
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14
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Rahimi K. Tunable electronic properties of the novel g-ZnO/1T-TiS 2 vdW heterostructure by electric field and strain: crossovers in bandgap and band alignment types. Phys Chem Chem Phys 2020; 22:7412-7420. [PMID: 32215418 DOI: 10.1039/d0cp00524j] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A relatively new and promising method to tune properties of monolayers is by forming a heterostructure of them. Here, the van der Waals heterostructure of graphene-like zinc oxide (g-ZnO) and 1-trigonal titanium disulfide (1T-TiS2) was formed and its structural, electronic, and optical properties were studied in the framework of density functional theory. The dynamical stability of the heterostructure was confirmed based on its phonon band structure. An indirect (Γ → M) bandgap of 0.65 eV, a large built-in electric field (or a large potential drop of 3.12 eV), a type-II (staggered) band alignment, and a large conduction band offset of 2.94 eV were found to form across the interface, which are all desirable for potentially efficient separation of charge carriers. We showed also that the formation of the heterostructure largely enhances the almost-zero optical absorption of g-ZnO in visible and near-infrared regions, which is desirable for optoelectronic applications. By applying a perpendicular electric field, we could tune the bandgap value and the band alignment type (type-II → type-I) of the heterostructure. Finally, we showed that by applying compressive strain, one can change the band alignment type (type-II → type-I) and by applying tensile strain, the bandgap value could be tuned and a crossover occurs in the bandgap type (indirect → direct → indirect).
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Affiliation(s)
- Kourosh Rahimi
- Condensed Matter Group, Department of Basic Sciences, Tarbiat Modares University, Jalal-Ale-Ahmad Avenue, Tehran, Iran.
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15
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Liu H, Zakhtser A, Naitabdi A, Rochet F, Bournel F, Salzemann C, Petit C, Gallet JJ, Jie W. Operando Near-Ambient Pressure X-ray Photoelectron Spectroscopy Study of the CO Oxidation Reaction on the Oxide/Metal Model Catalyst ZnO/Pt(111). ACS Catal 2019. [DOI: 10.1021/acscatal.9b02883] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hang Liu
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, 4 Place Jussieu, 75005 Paris, France
- School of Materials Science and Engineering, Northwestern Polytechnical University, 127, Youyi Road, 710072 Xi’an, Shaanxi, China
| | - Alter Zakhtser
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, 4 Place Jussieu, 75005 Paris, France
- Sorbonne Université, CNRS, MONARIS, UMR 8233, 4 Place Jussieu, 75005 Paris, France
| | - Ahmed Naitabdi
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, 4 Place Jussieu, 75005 Paris, France
| | - François Rochet
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, 4 Place Jussieu, 75005 Paris, France
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Fabrice Bournel
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, 4 Place Jussieu, 75005 Paris, France
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Caroline Salzemann
- Sorbonne Université, CNRS, MONARIS, UMR 8233, 4 Place Jussieu, 75005 Paris, France
| | - Christophe Petit
- Sorbonne Université, CNRS, MONARIS, UMR 8233, 4 Place Jussieu, 75005 Paris, France
| | - Jean-Jacques Gallet
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, 4 Place Jussieu, 75005 Paris, France
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - Wanqi Jie
- School of Materials Science and Engineering, Northwestern Polytechnical University, 127, Youyi Road, 710072 Xi’an, Shaanxi, China
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16
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Chen H, Lin L, Li Y, Wang R, Gong Z, Cui Y, Li Y, Liu Y, Zhao X, Huang W, Fu Q, Yang F, Bao X. CO and H2 Activation over g-ZnO Layers and w-ZnO(0001). ACS Catal 2018. [DOI: 10.1021/acscatal.8b03687] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Hao Chen
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Le Lin
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People’s Republic of China
| | - Yifan Li
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, People’s Republic of China
| | - Rui Wang
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 398 Ruoshui Road, Suzhou 215123, People’s Republic of China
- Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, People’s Republic of China
| | - Zhongmiao Gong
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 398 Ruoshui Road, Suzhou 215123, People’s Republic of China
| | - Yi Cui
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 398 Ruoshui Road, Suzhou 215123, People’s Republic of China
| | - Yangsheng Li
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Yun Liu
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People’s Republic of China
| | - Xinfei Zhao
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Wugen Huang
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Qiang Fu
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People’s Republic of China
| | - Fan Yang
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People’s Republic of China
| | - Xinhe Bao
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, People’s Republic of China
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17
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Thang HV, Pacchioni G. Electronic structure of Al, Ga, In and Cu doped ZnO/Cu(111) bilayer films. Phys Chem Chem Phys 2018; 21:369-377. [PMID: 30525148 DOI: 10.1039/c8cp06717a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The effect of doping with group-III metals (Al, Ga and In) and Cu free standing and Cu(111) supported ZnO bilayer films has been investigated computationally by using the DFT+U method including dispersion contributions. The changes in the electronic properties of doped ZnO and ZnO/Cu(111) films have been tested by adsorbing CO probe molecules. The replacement of a lattice Zn ion in a free-standing ZnO bilayer by a group-III element generates an extra electron whose distribution depends on the dopant. In particular, while the excess electron is delocalized over the conduction band for Al or Ga doping, it is localized on the dopant in the case of In. The situation is different on the supported ZnO/Cu(111) film, where the extra electron is transferred to the underlying Cu support. While the CO adsorption energy at the doped sites in the ZnO bilayer is the same as in the ZnO/Cu(111) ultrathin films, CO exhibits a larger red-shift in the unsupported ZnO bilayer. The oxidation state of Cu replacing Zn in the unsupported ZnO films is 2+, Cu(3d9) state, while it is 1+, Cu(3d10) state, in the ZnO/Cu(111) supported films where a charge transfer from the supporting Cu metal to the Cu impurity occurs. Cu doping results in a stronger interaction with CO and a large red-shift of the CO stretching frequency. In this respect, Cu doping of ZnO/Cu(111) bilayer films could have interesting consequences in gas adsorption while doping with group-III elements does not lead to major changes of the adsorption properties when the free-standing ZnO films are compared to the supported ZnO/Cu(111) counterparts.
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Affiliation(s)
- Ho Viet Thang
- Departimento di Scienza dei Materiali, Università di Milano-Bicocca, via Cozzi 55, 20125 Milano, Italy.
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18
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19
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Ro I, Resasco J, Christopher P. Approaches for Understanding and Controlling Interfacial Effects in Oxide-Supported Metal Catalysts. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02071] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Insoo Ro
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93117, United States
| | - Joaquin Resasco
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93117, United States
| | - Phillip Christopher
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93117, United States
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20
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Hamlyn RCE, Mahapatra M, Grinter DC, Xu F, Luo S, Palomino RM, Kattel S, Waluyo I, Liu P, Stacchiola DJ, Senanayake SD, Rodriguez JA. Imaging the ordering of a weakly adsorbed two-dimensional condensate: ambient-pressure microscopy and spectroscopy of CO2 molecules on rutile TiO2(110). Phys Chem Chem Phys 2018; 20:13122-13126. [DOI: 10.1039/c8cp01614c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Disorder–order transitions found for CO2 on titania.
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Affiliation(s)
- Rebecca C. E. Hamlyn
- Chemistry Department
- Brookhaven National Laboratory
- Upton
- USA
- Department of Chemistry
| | | | | | - Fang Xu
- Chemistry Department
- Brookhaven National Laboratory
- Upton
- USA
| | - Si Luo
- Chemistry Department
- Brookhaven National Laboratory
- Upton
- USA
| | | | - Shyam Kattel
- Chemistry Department
- Brookhaven National Laboratory
- Upton
- USA
| | | | - Ping Liu
- Chemistry Department
- Brookhaven National Laboratory
- Upton
- USA
| | | | | | - José A. Rodriguez
- Chemistry Department
- Brookhaven National Laboratory
- Upton
- USA
- Department of Chemistry
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21
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Palomino RM, Ramírez PJ, Liu Z, Hamlyn R, Waluyo I, Mahapatra M, Orozco I, Hunt A, Simonovis JP, Senanayake SD, Rodriguez JA. Hydrogenation of CO2 on ZnO/Cu(100) and ZnO/Cu(111) Catalysts: Role of Copper Structure and Metal–Oxide Interface in Methanol Synthesis. J Phys Chem B 2017; 122:794-800. [DOI: 10.1021/acs.jpcb.7b06901] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Robert M. Palomino
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Pedro J. Ramírez
- Facultad
de Ciencias, Universidad Central de Venezuela, Caracas 1020-A, Venezuela
| | - Zongyuan Liu
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Rebecca Hamlyn
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Iradwikanari Waluyo
- Photon
Sciences Division, National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Mausumi Mahapatra
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Ivan Orozco
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Adrian Hunt
- Photon
Sciences Division, National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Juan P. Simonovis
- Photon
Sciences Division, National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Sanjaya D. Senanayake
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - José A. Rodriguez
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
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22
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Weng X, Zhang K, Pan Q, Martynova Y, Shaikhutdinov S, Freund HJ. Support Effects on CO Oxidation on Metal-supported Ultrathin FeO(1 1 1) Films. ChemCatChem 2017. [DOI: 10.1002/cctc.201601447] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Xuefei Weng
- Abteilung Chemische Physik; Fritz-Haber-Institut der Max-Planck-Gesellschaft; Faradayweg 4-6 14195 Berlin Germany
| | - Ke Zhang
- Abteilung Chemische Physik; Fritz-Haber-Institut der Max-Planck-Gesellschaft; Faradayweg 4-6 14195 Berlin Germany
| | - Qiushi Pan
- Abteilung Chemische Physik; Fritz-Haber-Institut der Max-Planck-Gesellschaft; Faradayweg 4-6 14195 Berlin Germany
| | - Yulia Martynova
- Abteilung Chemische Physik; Fritz-Haber-Institut der Max-Planck-Gesellschaft; Faradayweg 4-6 14195 Berlin Germany
| | - Shamil Shaikhutdinov
- Abteilung Chemische Physik; Fritz-Haber-Institut der Max-Planck-Gesellschaft; Faradayweg 4-6 14195 Berlin Germany
| | - Hans-Joachim Freund
- Abteilung Chemische Physik; Fritz-Haber-Institut der Max-Planck-Gesellschaft; Faradayweg 4-6 14195 Berlin Germany
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23
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Wang Y, Wöll C. IR spectroscopic investigations of chemical and photochemical reactions on metal oxides: bridging the materials gap. Chem Soc Rev 2017; 46:1875-1932. [DOI: 10.1039/c6cs00914j] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this review, we highlight recent progress (2008–2016) in infrared reflection absorption spectroscopy (IRRAS) studies on oxide powders achieved by using different types of metal oxide single crystals as reference systems.
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Affiliation(s)
- Yuemin Wang
- Institute of Functional Interfaces
- Karlsruhe Institute of Technology
- Eggenstein-Leopoldshafen
- Germany
| | - Christof Wöll
- Institute of Functional Interfaces
- Karlsruhe Institute of Technology
- Eggenstein-Leopoldshafen
- Germany
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24
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Kumagai T, Liu S, Shiotari A, Baugh D, Shaikhutdinov S, Wolf M. Local electronic structure, work function, and line defect dynamics of ultrathin epitaxial ZnO layers on a Ag(1 1 1) surface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:494003. [PMID: 27731306 DOI: 10.1088/0953-8984/28/49/494003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Using combined low-temperature scanning tunneling microscopy and Kelvin probe force microscopy we studied the local electronic structure and work function change of the (0 0 0 1)-oriented epitaxial ZnO layers on a Ag(1 1 1) substrate. Scanning tunneling spectroscopy (STS) revealed that the conduction band minimum monotonically downshifts as the number of the ZnO layers increases up to 4 monolayers (ML). However, it was found by field emission resonance (FER) spectroscopy that the local work function of Ag(1 1 1) slightly decreases for 2 ML thick ZnO but it dramatically changes and drops by about 1.2 eV between 2 and 3 ML, suggesting a structural transformation of the ZnO layer. The spatial variation of the conduction band minimum and the local work function change were visualized at the nanometer scale by mapping the STS and FER intensities. Furthermore, we found that the ZnO layers contained line defects with a few tens of nm long, which can be removed by the injection of a tunneling electron into the conduction band.
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25
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Applicability of MOS structures in monitoring catalytic properties, as exemplified for monolayer-iron-oxide-coated porous platinum films. J Catal 2016. [DOI: 10.1016/j.jcat.2016.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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26
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27
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Oxidation of Small Supported Platinum-based Nanoparticles Under Near-Ambient Pressure Exposure to Oxygen. Top Catal 2016. [DOI: 10.1007/s11244-015-0529-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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28
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Pan Q, Weng X, Chen M, Giordano L, Pacchioni G, Noguera C, Goniakowski J, Shaikhutdinov S, Freund HJ. Enhanced CO Oxidation on the Oxide/Metal Interface: From Ultra-High Vacuum to Near-Atmospheric Pressures. ChemCatChem 2015. [DOI: 10.1002/cctc.201500394] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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