Springer Handbook of Advanced Catalyst Characterization

Preface
Editors´ Introduction
References
Contents
About the Editors
Contributors
Part I: Vibrational Spectroscopy
1 Infrared (IR) Spectroscopy
1.1 Introduction
1.2 Principles of Vibrational Spectroscopy
1.3 Experimental Techniques
1.4 The Bulk Characterization of Solid Catalysts by Infrared Spectroscopy
1.4.1 IR Absorption Spectra of Crystalline Nonconducting Solids
1.4.2 IR Absorption Spectra of Amorphous Solids
1.4.3 IR Characterization of Spent Catalysts
1.4.4 Infrared Detection of Impurities in Catalysts
1.4.5 Application of Skeletal IR Spectroscopy in the Characterization of Unsupported and Supported Metal Nanoparticles
1.4.6 Revealing the State of Oxidation of Catalysts by Skeletal IR Spectroscopy
1.5 Surface Characterization of Catalysts by IR Spectroscopy
1.5.1 The Infrared Spectra of Pure Catalyst Powders
Line-Base Slope and Light Scattering
The Cutoff
The Bulk Vibration Overtones
Spectra of Surface or Bulk Impurities
The IR Spectra of the Surface Hydroxyl Groups
Absorptions Due to Surface Metal-Oxygen ``Double´´ Bonds
Absorptions by Surface Metal-Oxygen-Metal Bridges
1.5.2 The IR Spectra of Adsorbed Probe Molecules
IR Spectra of Basic Probes for Surface Acidity Characterization
IR Spectra of Acidic Probes for Surface Basicity Characterization
IR Spectra of Adsorbed Carbon Monoxide for Metallic/Cationic Sites Characterization
1.6 Application of IR Spectroscopy to the Study of the Mechanisms of Heterogeneous Catalysis
1.7 Conclusions
References
2 Case Studies: Infrared (IR) Spectroscopy
2.1 The FT-IR Experimental Setups
2.2 Case Study 1: Formation of Cu Nitrates on Cu-CHA Catalyst by Operando FT-IR
2.2.1 The Catalyst
2.2.2 Effect of Temperature on the NO/O2 Reactivity on Cu-CHA
Operando FT-IR Spectroscopy at Fixed Temperature
Operando FT-IR Spectroscopy at Variable Temperature
2.2.3 Interpretation of the Bands
2.2.4 In Situ FT-IR Spectroscopy Monitoring Nitrates Formation with Isotopic Labelled 15NO
2.3 Case Study 2: Dynamic Behavior of Pt-Hydrides on a Pt/Al2O3 Catalyst
2.3.1 The Catalyst
2.3.2 Pt-Hydride Species as a Function of the H2 Concentration
In Situ FT-IR Spectroscopy in Transmission Mode
Operando FT-IR Spectroscopy in Transmission Mode
Operando FT-IR Spectroscopy in DRIFT Mode
2.3.3 Explaining the Dynamic Behavior of the Pt-H Species
2.3.4 The Behavior of the Pt-Hydrides During a Hydrogenation Reaction
2.4 Conclusions
References
3 Reflection Absorption Infrared Spectroscopy
3.1 Introduction
3.2 Case Studies
3.2.1 Hydrocarbons on Metallic and Single-Atom Alloy Surfaces
3.2.2 Adsorption of Methanol on Palladium
3.2.3 CO2 Activation on a ZrO2 Film
3.2.4 CO on Metallic, Bimetallic, and Single-Atom Alloy (SAA) Surfaces
3.3 Conclusion
References
4 Raman Spectroscopy
4.1 Introduction
4.2 Description of Raman Method
4.2.1 Theory of Raman Scattering
4.2.2 Benefits of Raman Spectroscopy for Characterization of Catalysts
4.2.3 Limitations of Raman Spectroscopy for Characterization of Catalysts
4.2.4 Comparison of Method to Other Techniques: Pros and Cons
4.3 Description of General Raman System to Conduct Characterization of Catalysts
4.3.1 Excitation Source
4.3.2 Sample Illumination and Light Collection System
4.3.3 Sample Holder
4.3.4 Detection System
4.4 New Instrumental Advances in Raman Spectroscopy
4.4.1 Avoidance of Fluorescence Effect
4.4.2 Increase Sensitivity
4.4.3 Increase Spatial Resolution
4.5 Description of Reaction Cells for In Situ and Operando Raman Studies
4.6 Chronology of Application of Raman Spectroscopy to Catalysis
4.6.1 Early Ambient Conditions and In Situ Condition
4.6.2 Reaction Conditions: In Situ/Operando Measurement
4.7 Time-Resolved Raman Spectroscopy
4.8 Spatial-Resolved Raman Spectroscopy: Microscopy
4.9 Modulation Excitation Raman Spectroscopy
4.10 Applications of Raman Spectroscopy to Catalyst Synthesis
4.11 Applications of Raman Spectroscopy Study to Catalyst Treatments
4.12 Applications of Raman Spectroscopy to Catalyst Structure-Activity Relationships
4.13 Combining Raman Spectroscopy with Other Techniques (Multimodal)
4.14 Summary
References
5 Case Studies: Raman Spectroscopy
5.1 Introduction
5.2 In Situ Raman Spectroscopy
5.3 Case Studies on the Application of Operando Raman Spectroscopy to Heterogeneous Catalysts
5.3.1 Case Studies
Case Study 1: The Three Generations of Characterization of Zirconia-Supported Vanadium Oxide Catalysts
Case Study 2: Operando Raman Spectroscopy and Density Functional Theory-Based Vibrational Assignment
Case Study 3: Recent Studies on the Operando Raman Spectroscopy Identification of Coke During Heterogeneously Catalyzed Reacti...
5.4 Present Challenges and Future Recourse
References
6 Ultraviolet (UV) Raman Spectroscopy
6.1 Introduction
6.2 Description of Raman Spectroscopy
6.2.1 Raman Scattering Theory
6.2.2 Benefits and Limitations for Catalyst Characterization
6.3 UV Raman Instrumentation
6.4 New Instrument Advances
6.5 Reaction Cells
6.6 Chronology of Application to Catalysis
6.7 Time Resolution
6.8 Spatial Resolution
6.9 Applications of UV Raman
6.9.1 Silica/Zeolite Synthesis
6.9.2 Thermal, Oxidation, and Reduction Treatments
6.9.3 Catalyst Deactivation by Coke Formation
6.9.4 Speciation of Titania
6.9.5 Supported Vanadium Oxide
6.9.6 Ceria Support
6.10 Multimodal Operation
6.11 Conclusions and Future Outlook
References
7 Surface Enhanced Raman Spectroscopy (SERS)
7.1 Introduction
7.2 Raman Scattering
7.3 Surface-Enhanced Raman Scattering (SERS)
7.3.1 The Electromagnetic Effect in SERS
7.3.2 Chemical Mechanism (CT)
7.4 Surface-Enhanced Resonance Raman Scattering (SERRS)
7.5 Surface Selection Rules
7.6 SERS Active Substrates
7.6.1 Metallic Nanoparticles
7.6.2 Highly Ordered Substrates
7.6.3 Hybrid Materials
7.7 Tip-Enhanced Raman Scattering
7.8 SERS Imaging
7.9 SERS Applications in Catalysis
7.10 Conclusions
References
8 Nanoscale Raman Spectroscopy
8.1 Short Introduction to TERS
8.2 Theoretical Background of Plasmon-Induced Catalysis
8.2.1 Thermal Effects
8.3 Nanoscale Spectroscopic Investigation of Catalyzed Reactions
8.4 Nanoscale Catalytic Reactions with Plasmon Contribution
8.4.1 pNTP and pATP Dimerization to DMAB and Other Azo Bridge Containing Molecules
8.4.2 Triple Bond Formation
8.4.3 (De)Protonation of Pyridine
8.4.4 Miscellaneous: Bond Cleavages
8.5 Electrochemical Processes Using EC-AFM-TERS and EC-STM-TERS
8.5.1 Reversible Redox Reaction of Nile Blue
8.5.2 Protonation Reactions
8.5.3 Cleavage of Water
8.5.4 Manipulating Phthalocyanine
8.6 Catalytic Reactions Without Plasmon Contribution
8.6.1 Porphyrin and Phthalocyanine: NO, CO, O, O2 Complexation
8.6.2 Bimetallic Substrates: Oxidation on Au/Pd and Au/Pt Surfaces
8.6.3 Cis-Trans Isomerization Around an Azo Bridge
8.7 Conclusion
References
9 Operando Electrochemical Raman Spectroscopy
9.1 Introduction
9.2 Raman Spectroscopy
9.2.1 Basic Principle
9.2.2 Instrumentation
9.3 Surface-Enhanced Raman Spectroscopy
9.3.1 Surface-Enhanced Raman Spectroscopy
9.3.2 SERS Substrates and Fabrication
9.3.3 Extensions of SERS
9.4 Operando Electrochemical Raman Spectroscopy in Electrocatalysis
9.4.1 Coupling Raman Spectroscopy and Electrochemistry
9.4.2 Central Topics in Electrocatalysis
9.4.3 Case Studies on Electrocatalytic Energy Conversion
Water Electrolysis: OERS and SECM
The Oxygen Reduction Reaction (ORR): OERS and SHINERS
The Carbon Dioxide Reduction Reaction (CO2RR): OERS and SERS
9.5 Experiences from a Practical Point of View
9.6 Conclusion
References
10 Sum Frequency Generation (SFG) Spectroscopy
10.1 Introduction to Sum Frequency Generation (SFG) Spectroscopy
10.2 SFG Theory
10.2.1 SFG Signal Intensity and Lineshape
10.3 SFG Instrumentation and Operation Modes
10.4 Applications of SFG Spectroscopy and Selected Case Studies
10.4.1 SFG Spectroscopy on Metal Surfaces
SFG Spectroscopy on Metal Single Crystals
SFG Spectroscopy on Supported Metal Nanoparticles
10.4.2 SFG Spectroscopy on Oxide Surfaces
10.4.3 SFG Spectroscopy on Polymer and Biomaterial Interfaces
10.4.4 SFG Spectroscopy of Water and Ice Layers
10.5 Synopsis
References
Part II: Electron and Photoelectron Spectroscopy
11 Ultraviolet-Visible (UV-Vis) Spectroscopy
11.1 Basic Principles of Ultraviolet-Visible Spectroscopy
11.2 The Spectrometer and Related Accessories
11.2.1 The UV-Vis Spectrometer
11.2.2 Sample Preparation, Mode of Measuring, and Catalytic Reactors
Transmission Spectroscopy
Diffuse Reflectance Spectroscopy
Fiber Optics Spectroscopy
Micro-Spectroscopy
11.3 Probe Molecule UV-Vis Spectroscopy
11.4 Coupling UV-Vis Spectroscopy with Other Analytical Methods
11.5 Complementing Data Interpretation with Density Functional Theory
11.6 Application of Chemometrics and Multivariate Analyses
11.7 Selected Applications of UV-Vis Spectroscopy in the Field of Catalysis
11.7.1 Heterogeneous Catalysis
11.7.2 Homogeneous Catalysis
11.7.3 Electrocatalysis
11.7.4 Photocatalysis
11.8 Conclusions and Outlook
References
12 Case Studies: Ultraviolet-Visible (UV-Vis) Spectroscopy
12.1 Introduction
12.2 NH3-SCR Over Supported Vanadium/Copper Catalysts
12.3 Dehydrogenation of Propane Over Supported Catalysts
12.4 Electroreduction of CO2 Over Molecular Catalysts
12.5 Methanol to Olefin (MTO) Process Over Zeolite Catalysts
12.6 Conclusions and Remarks
References
13 Fluorescence Microscopy
13.1 Introduction
13.2 Reactivity and Heterogeneity of Individual Particles
13.3 Restructuring and Switching
13.4 Super-resolution Mapping of Catalytic Activities at the Single to Subparticle Level
13.5 Scalable Parallel Screening of Catalyst Activities
13.6 Spatial and Temporal Catalysis Cooperativity Within and Between Nanoparticles
13.7 Conclusion
References
14 Photoluminescence (PL) Spectroscopy
14.1 Introduction
14.2 Basic Principles of Photoluminescence
14.2.1 Absorption Spectrum, Franck-Condon Principle, and Vibration Structure
14.2.2 The Fate of Electronic Excitation Energy
Excitation, Emission (Fluorescence), and Stokes Shift
Excited Triplet State, Intersystem Crossing, Phosphorescence, and Selection Rules
Vibrational Deactivation and Internal Conversion
Radiative Processes on Semiconducting Catalyst: Effect of the Adsorption of Various Reactant Molecules Upon the Radiative Proc...
14.3 Practical Aspects of Photoluminescence
14.3.1 Instrumentation
14.3.2 Sample Preparation
14.3.3 Spectral Parameters to Identify Photoluminescence Sites
14.3.4 Wavelength and Spectral Shape
14.3.5 Quantum Efficiency
14.3.6 Lifetimes and the Stern-Volmer Expression
14.3.7 Energy Transfer and Migration
14.3.8 Ultrafast Time-Resolved PL Spectroscopy
14.3.9 Relevance of Photoluminescence to Surface Phenomena
14.4 Characterization of Catalytically Active Sites by In Situ Photoluminescence Spectroscopy
14.4.1 Ti-Oxide Single-Site Containing Samples
14.4.2 V-Oxide Single-Site Containing Samples
14.4.3 Mo-Oxide Single-Site Containing Samples
14.4.4 Carbon Containing Samples
14.5 Characterization of Acidic and Basic Sites by Means of Luminescent Probe Molecules and In Situ Photoluminescence Spectros...
14.6 In Situ Photoluminescence Studies of Photocatalytic Processes Involving Inorganic and Organic Semiconductor Photocatalyti...
14.7 Effect of Temperature on Photoluminescence Spectra
14.8 Effect of Magnetic Fields on Photoluminescence Spectra
14.9 Conclusions and Outlook
References
15 Case Studies: Photoluminescence (PL) Spectroscopy
15.1 Investigation of Charge Carrier Dynamics in Photocatalysts
15.1.1 Time-Resolved PL Studies of Pure and Doped TiO2 Nanoparticles
15.1.2 PL Studies of Reactant Interactions with TiO2 Nanoparticles
15.1.3 PL Investigation of Charge Carrier Separation in g-C3N4 Heterojunctions
15.2 Investigation of Photocatalytic Reactions Promoted by Supported Transition Metal Ions
15.2.1 NO Photo-Reduction by CO on Mo6+/SiO2
15.2.2 Photo-PROX Reaction on Visible Light Responsive Cr6+-MCM-41
References
16 Near Ambient Pressure (NAP) X-Ray Photoelectron Spectroscopy (XPS)
16.1 Introduction
16.2 Technical Issues
16.3 Applications of NAP-XPS
16.3.1 CO Oxidation
16.3.2 CO2 Hydrogenation and Methanol Synthesis
16.3.3 Methane Activation and Conversion
16.4 Conclusion
References
17 Case Studies: Near Ambient Pressure (NAP) X-Ray Photoelectron Spectroscopy (XPS)
17.1 Case Study: Monitoring Catalyst Preparation and Formation of Active Catalytic Sites
17.2 Case Study: Tracking Adsorbate on Catalyst Formed Under Catalytic Conditions
17.3 Case Studies: Observing Compositional Restructuring of a Catalyst Driven by a Reaction
17.4 Summary
References
Part III: Electron Microscopy
18 Scanning Electron Microscopy (SEM)
18.1 Introduction
18.2 Instrumental Considerations
18.2.1 Origin of Signals Used for Image Formation in SEM
18.2.2 Types of Detectors Used in SEM
Secondary Electron Detectors
Backscattered Electron Detectors
Transmitted Electron Detectors in the SEM
18.2.3 Choice of Operating Voltage
18.2.4 What Determines Image Resolution
18.2.5 Quantifying Resolution in SEM
18.2.6 Correlating SEM Data with XRD
18.2.7 Applying Bias to the Specimen to Enhance Resolution
18.2.8 Performing SEM in a STEM for Imaging the Location of Single Atoms
18.2.9 Performing STEM in an SEM for Improved Resolution
18.2.10 Elemental Analysis via EDS and WDS
18.2.11 Electron Backscatter Diffraction (EBSD)
18.3 Applications of SEM to the Study of Heterogeneous Catalysts
18.3.1 Study of Surface Facets in Nanoparticles
18.3.2 Determining Location of Nanoparticles, Within the Pores or on the External Surface?
18.3.3 Confinement of Pt in Mesoporous Silica to Improve Sinter Resistance
18.3.4 Electron Backscatter Diffraction to Determine Facet Orientation in Cu Catalysts for CO2 Electroreduction
18.3.5 Interaction of Plasmonic Ag Nanoparticles with High-Energy Sites on TiO2 Studied via SEM-EBSD
18.3.6 In Situ Study of Ag-Cu Catalysts for Ethylene Epoxidation
18.3.7 In Situ Imaging and Spectroscopy of Liquids in an SEM
18.3.8 Imaging the Formation of Graphene Layers During In Situ Growth
18.4 Perspective
References
19 High Pressure Transmission Electron Microscopy (TEM)
19.1 General Principles
19.1.1 Why High-Pressure Transmission Electron Microscopy?
19.1.2 Basic Principles of TEM and STEM Modes with a Standard Instrument
19.2 Environmental Transmission Electron Microscopes (ETEM)
19.2.1 General Setup for ETEM
19.2.2 Advantages and Drawbacks of ETEM
19.3 Environmental Holder
19.3.1 General Setup for Environmental Holder Use
19.3.2 Advantages and Disadvantages of Environmental Holders
19.4 Detection Systems for Imaging and Spectroscopy with ETEM and Environmental Holders
19.4.1 General Overview of EDS and EELS
19.4.2 Considerations for EDS, EELS, Imaging, and Diffraction with In Situ Experiments
19.5 Examples of ETEM Applications
19.5.1 Oxidation and Reduction Effect on Dealloyed Nanoporous Gold [42]
19.5.2 Change of the Crystal Structure of Au Nanoparticles and Adsorption of CO Molecules [48]
19.5.3 In Situ Manipulation of the Active Au-TiO2 Interface with Atomic Precision During CO Oxidation [51]
19.6 Examples of Environmental Holder Applications
19.6.1 Ostwald Ripening and Particle Migration and Coalescence (PMC) Phenomena [55]
19.6.2 Structural Dynamics of Nanoparticles Revealed by a Combination of In Situ TEM and XAFS [57]
19.6.3 Visualization of Nanoparticle Growth [60]
19.6.4 Direct Observation of Kirkendall Effect in Nanoparticles with a Liquid-Heating In Situ Holder [63]
19.6.5 Photoelectrocatalysis for the Generation of H2
19.6.6 Structural Evolution During Photocorrosion of Ni/NiO Core/Shell Co-Catalyst on TiO2 [74, 75]
19.7 Common Questions That Users Should Ask Themselves Before Starting an In Situ Experiment
19.8 Future Perspective for In Situ TEM at High Pressures
References
20 STEM High Angle Annular Dark-Field Imaging
20.1 Introduction
20.1.1 Image Formation in STEM
20.1.2 Forming an Electron Probe
20.1.3 Electron-Matter Interactions and HAADF Image Formation
20.2 Some Case Studies of STEM-HAADF Imaging for Catalyst Research
20.2.1 STEM Imaging of Supported Metal Catalysts
Gold-on-Oxide Supports for Low-Temperature CO Oxidation
Matching Different Forms of Gold to Different Catalytic Reactions
Supported Bimetallic Au-Pd Catalysts
20.2.2 STEM-HAADF Imaging of Supported Metal Oxide Catalysts: The WOx/ZrO2 Solid Acid Catalyst
20.2.3 STEM-HAADF Imaging of Bulk Mixed Oxide Catalysts
Introduction to M1 and M2 Catalysts
Confirming the M1 and M2 Structures with STEM-HAADF Imaging
STEM-HAADF Studies of Lateral Surfaces
STEM-HAADF Studies of Dynamic Catalyst Structures
20.3 ``Gentle´´ STEM-HAADF Imaging
20.3.1 Low-Voltage STEM Imaging of Catalysts Comprised of Beam-Sensitive 2D-Layered Materials or Nanostructured Carbon
Direct Identification of MNx Species in Carbon-Based Electrocatalysts
Identification of Active Structures in 2D MoS2-Based Catalysts
20.3.2 Low-Dose STEM-HAADF Imaging of Zeolite-Type Materials
20.4 3D Imaging of Catalysts via STEM-HAADF
20.4.1 STEM-HAADF Tomography
20.4.2 Depth Sectioning with Through-Focal STEM-HAADF Imaging
20.4.3 Quantitative STEM-HAADF Imaging
20.4.4 Comparison of 3D STEM-HAADF Imaging Methods
20.5 STEM-HAADF Imaging of Catalysts in a More Realistic Working Environment
20.6 Summary
References
21 Case Studies: Aberration Corrected High-Angle Annular Dark-Field (AC-HAADF) Microscopy
21.1 Case Studies of Molybdenum Carbide-Supported Metal Catalysts
21.1.1 Supported Pt/α-MoC Catalyst for Low-Temperature Aqueous-Phase Reforming of Methanol (APRM)
21.1.2 Supported Au/α-MoC Catalyst for Low-Temperature WGS Reaction
21.1.3 α-MoC-Supported Light Transition Metal Catalysts: Ni/α-MoC and (Co-Ni)/α-MoC
21.2 Conclusions and Perspectives
References
Part IV: Particle Scattering
22 Low Energy Ion Scattering (LEIS) Spectroscopy
22.1 Introduction
22.2 Descriptions of LEIS
22.2.1 Fundamentals
22.2.2 Quantification
22.2.3 Depth Information
22.2.4 Pretreatments
22.3 Application of LEIS to Heterogeneous Catalysts
22.3.1 Dispersion of the Active Component
22.3.2 Surface Compositions of Supported Bimetal Catalysts
22.3.3 Catalytically Active Surface Sites
22.3.4 Nanocatalysts with Core-Shell Structures
22.3.5 Strong Metal-Support Interaction
22.3.6 Other Applications
22.4 Summary and Outlook
References
23 Case Studies: Low Energy Ion Scattering (LEIS) Spectroscopy
23.1 Case Study: LEIS Surface Analysis of Photocatalysts
23.2 Case Study: LEIS Surface Analysis of Bulk Mixed Metal Oxide Catalysts
23.3 Case Study: LEIS Surface Analysis of Supported Metal Oxide Catalysts
23.4 Case Study: LEIS Surface Analysis of Isotopically 18O-16O Exchanged Bulk Metal Catalysts
23.5 Summary/Conclusions
References
24 Neutron Scattering (NS) Spectroscopy
24.1 Introduction
24.2 Theory of Neutron Scattering
24.2.1 Properties of Neutrons and Neutron Sources
24.2.2 How Neutron Scattering Works
24.2.3 Instrumentation
24.2.4 Modeling
24.3 Pros and Cons of Neutron Scattering for Catalysis Research
24.4 Inelastic Neutron Spectroscopy (INS)
24.4.1 Basic Principles of INS
24.4.2 Application of INS to Heterogeneous Catalysis
24.5 Quasi-Elastic Neutron Scattering (QENS)
24.5.1 Basic Principles of QENS
24.5.2 Application of QENS to Heterogeneous Catalysis
24.6 Neutron Diffraction (ND)
24.6.1 Basic Principles of ND
24.6.2 Application of ND to Heterogeneous Catalysis
24.7 Other Neutron Scattering Techniques for Heterogeneous Catalysis
24.8 Summary
References
Part V: X-Ray Methods
25 X-Ray Diffraction (XRD)
25.1 Introduction
25.2 Physics of XRD
25.2.1 Sources of X-Rays
25.2.2 XRD
25.3 Crystalline Solids and XRD
25.4 Understanding X-Ray Diffractograms
25.5 Toward In Situ and Operando XRD Characterization of Catalysts
25.6 Case Studies Highlighting In Situ/Operando XRD in Catalyst Characterization
25.6.1 A Tailored Multifunctional Catalyst for Ultraefficient Styrene Production Under a Cyclic Redox Scheme
25.6.2 In Situ Studies of the Active Sites for the Water-Gas Shift (WGS) Reaction Over Cu-CeO2 Catalysts:Complex Interaction B...
25.6.3 Combined In Situ X-Ray Powder Diffractometry/Raman Spectroscopy of Iron Carbide and Carbon Species Evolution in Fe(-Na-...
25.7 Limitations of XRD
25.8 Outlook
References
26 Case Studies: Crystallography as a Tool for Studying Methanol Conversion in Zeolites
26.1 Introduction
26.2 MTH Conversion
26.3 Diffraction for Zeolite Characterization
26.4 Organic Molecules Adsorbed in Zeolites
26.5 Catalysts ``Postmortem´´
26.6 In Situ Studies on Zeolites
26.7 Operando Catalytic Studies
26.8 Time- and Space-Resolved Operando Studies
26.9 Perspective
References
27 X-Ray Absorption Spectroscopy (XAS): XANES and EXAFS
27.1 Introduction
27.2 Recent Technical Developments for Operando XAS Studies of Catalysts and Catalysis: The Induction of Highly Time-Resolved,...
27.2.1 Fast, Single-Shot, Fluorescence-Yield XAS Using a Passivated Implanted Planar Silicon (PIPS) Diode Detector [36]
27.3 Recent Selected Examples of Advanced Operando XAS
27.3.1 Advances in Spatially Resolved Operando XAS: From Single Metal Nanoparticles to Reactors and from Two- to Three- to Fou...
One-Dimensional Spatial Investigation of Reactor Beds
``Nano-focus´´ XAS: Toward Interrogating Single Supported Nanoparticles
27.3.2 Operando XAS in Two and Three Dimensions
Quantifying Changes in Iron Speciation in LiFePO4 Battery Materials Using XAS Imaging
Operando Computed Tomography (CT) XANES of Structure and Speciation in Pt Cathodes in a PEM Fuel Cell
27.3.3 XAS on the Microseconds Timescale: Investigating Mechanisms of Photocatalysis
27.3.4 Electrochemistry/Catalysis: Novel Approaches to Combining XAFS with Electrochemical Techniques and Cells
The Importance of Pd Hydride Phases and Pd-Based PEMFC Fuel Cells [99]
The Role of Iron Dopants in Cobalt-Based Perovskite Catalysts in the Oxygen Evolution Reaction (OER)
The Nature, Stability, and Reversibility of Active Iron Phases Under Conditions of Hydrogen Evolution (HER)
27.3.5 Combined XAS and Photo-Electro-Catalysis
27.3.6 Operando XAS Goes Soft
27.3.7 Operando Studies Using Laboratory XAS Instruments
27.4 Checks, Balances, and Outlook
27.5 Conclusions
References
28 Time-Resolved X-Ray Absorption Spectroscopy (XAS)
28.1 Basic Concepts of X-Ray Spectroscopy
28.1.1 Interaction of X-Rays with Matter
28.1.2 The EXAFS Equation
28.2 The X-Ray Absorption Experiment
28.2.1 The X-Ray Source
Synchrotron Radiation Sources
Lab-Based X-Ray Absorption Spectroscopy
Free Electron Lasers
Soft Versus Hard X-Rays
28.2.2 Spectral Versus Time Resolution
28.2.3 Spatially Resolved X-Ray Absorption Spectroscopy
28.2.4 Choosing the Correct Experimental Mode
28.3 X-Ray Absorption Spectroscopy in Catalysis
28.4 Showcases from the Field of Heterogeneous Catalysis
28.4.1 Automotive Catalysis
28.4.2 Hydrogenation Catalysis
28.4.3 Electrocatalysis
28.4.4 Photocatalysis
28.5 Toward Ultrafast X-Ray Spectroscopy of Catalysts
28.6 Conclusions and Outlook
References
29 Case Studies: Time-Resolved X-Ray Absorption Spectroscopy (XAS)
29.1 Introduction
29.2 Multivariate Curve Resolution with Alternating Least Square (MCR-ALS) Analysis
29.2.1 Basic Concepts
29.2.2 Rank Determination of Matrix D
29.2.3 Initial Estimates
29.2.4 Limitations: Deviation of the Bilinearity Model for Evolutionary Data Set Recorded in Temperature
29.2.5 Limitations: Rank Deficiency by Existing Correlated Data
29.3 How Time Resolution Can Give Insights on ``Birth, Life, and Death´´ of Solid Catalysts
29.3.1 Preparation of Catalysts: From Solution Processes to Solid-State Reactions
Solution Preparation of Colloidal Particles
Synthesis of Supported Catalysts
Active-Phase Dispersion: Particle Size and Particle Density
Metal Distribution: Formation of Undesirable Phases and Interaction with the Support
Metal Distribution Within Bimetallic Particles
29.3.2 Catalysts in Operation: From Active Phases to Spent Catalysts
Insights of Catalyst Structure and Composition vs Activity: A Lever for Process Optimization
Catalyst Deactivation and Regeneration
29.4 Conclusion
References
30 X-Ray Absorption Spectroscopy (XAS): Surface Structural Determination of Alloy Nanoparticles
30.1 Introduction
30.2 Surface XAS of Alloy Metal Nanoparticle Catalysts: Basic Approach
30.3 Case Study 1: Incomplete Formation of a Pt3Cr Surface Alloy
30.4 Case Study 2: Identification of the Evolution of the Core-Shell Structures
30.5 Case Study 3: Identification of Bimetallic Alloy Compositions Suitable for Determination of Electronic Changes by XANES o...
30.6 Summary
References
31 Case Studies: Mapping Using X-Ray Absorption Spectroscopy (XAS) and Scattering Methods
31.1 Introduction
31.2 X-Ray Scattering-Based Imaging
31.3 X-Ray Absorption Spectroscopy-Based Imaging
31.4 X-Ray Coherent Diffraction Imaging
31.5 Conclusions
References
32 X-Ray Microscopy and Tomography
32.1 Introduction
32.1.1 A Brief Overview of X-Ray Microscopy and Tomography
32.1.2 Limitations of Integral or Conventional Catalyst Characterization
32.1.3 Advantages of Spatially Resolved Catalyst Characterization
32.1.4 The Role of Hard X-Ray Microscopy and Tomography in Catalysis
32.2 Motivation and Scope of This Chapter
32.2.1 The Target Audience
32.2.2 The Learning Curve in XRM and X-Ray CT
32.2.3 Summary: Aims and Objectives
32.3 Characteristics of X-Ray Imaging Methods
32.3.1 Laboratory X-Ray Sources and Synchrotron Light Sources
Characteristics of Synchrotron Radiation
32.3.2 Imaging in 2D vs. Tomography in 3D
Principles of X-Ray Tomography
Principles of Tomographic Reconstruction
Common Tomographic Reconstruction Algorithms
Scientific Resources for Tomography Data
Image Data Outputs in 2D and 3D
32.3.3 Scanning Probe Imaging vs. Full-Field Imaging
Full-Field Imaging
Scanning Probe Imaging
32.3.4 Spatial Resolution and Length Scale
Relevance of Spatial Resolution in Heterogeneous Catalysis
32.4 XRM in Catalysis: Molecular Information in Two and Three Dimensions
32.4.1 X-Ray Imaging Contrast Modes
Absorption Contrast Imaging
Fluorescence Contrast Imaging
Energy-Resolved XAS Imaging
Diffraction Contrast Imaging
Phase Contrast Imaging
32.4.2 Comparing Hard XRM and X-Ray CT to Other Microscopies
32.5 Notable Current and Developing Hard X-Ray Imaging Methods
32.5.1 Advanced XANES Tomography
32.5.2 X-Ray Ptychographic Microscopy and Tomography
32.5.3 Toward In Situ and Operando Tomography
32.5.4 Fourth-Generation and Diffraction-Limited Synchrotron Radiation Sources
32.6 Conclusions and Outlook
References
33 X-Ray Absorption Spectroscopy (XAS) Combined with Other Spectroscopic Techniques
33.1 Introduction
33.2 Examples
33.2.1 Study Case 1: XAS Combined with DRIFTS and MS
33.2.2 Study Case 2: XAS Combined with DRIFTS and MS
33.2.3 Study Case 3: XAS Combined with Transmission FT-IR and X-Ray Diffraction
33.3 Summary
References
Part VI: Magnetic Resonances
34 High-Field Nuclear Magnetic Resonance (NMR) Spectroscopy
34.1 A Brief Introduction of NMR for Catalyst Characterization
34.2 High-Field NMR and Quadrupolar Nuclei
34.3 High-Field 27Al MAS NMR
34.4 Vanadium Oxide Characterization
34.5 Energy Storage
34.6 Low-Natural Abundance, Low-Gamma Nuclei
34.7 Outlook
References
35 Nuclear Magnetic Resonance (NMR): Modern Methods
35.1 Introduction
35.2 NMR of Catalyst Support Surfaces
35.3 HF NMR of Supported Catalysts
35.4 HF NMR of Zeolites
35.4.1 Framework Structure
35.4.2 Acidity
35.5 HF NMR for MOFs
35.5.1 Introduction
35.5.2 NMR of Pristine MOFs
Metal Centers
Organic Linkers
35.5.3 Multivariate Metal-Organic Framework
Mixed Linkers
Mixed Metals in the Framework
Additional Metal Centers
35.5.4 NMR of Guest Molecules
35.6 Summary
References
36 Nuclear Magnetic Resonance (NMR): Physisorbed Xenon for Porosity
36.1 Introduction
36.2 Hyperpolarized Xenon
36.3 Generalities
36.4 Zeolites
36.4.1 Zeolites with Only One Type of Pore. Influence of the Structure
Experimental Results
Determination of the Mean Free Path [33, 34]
Influence of High Pressure
Influence of Temperature
Chemical Shift Anisotropy
36.4.2 Complex Structures and Mixtures of Zeolites
Zeolites with Complex Structures
Mixtures of Zeolites and with other Catalysts. Influence of the Structural Defects
Kinetics of Zeolite Crystallization
36.4.3 Influence of Strong Adsorption Sites
Theory
Influence of Cations
Alkali-Metal Cations
Divalent and Trivalent Cations with d0 Electronic Structure
Cations with dx Electronic Structure (x > 0)
36.4.4 Encumberment of Pores
Nonframework Aluminum
Poisoning of Catalysts: Coking
36.5 Other Microporous Materials
36.5.1 Polymers
36.5.2 Clays
36.5.3 Some Other Applications
Heteropolyoxometalate Salts
Porous Molecular Crystals
Industry
Archaeology
Biosensors
36.6 Supported Metals
36.7 Mesoporous Solids
36.8 Electric Field Gradient (EFG) in Porous Solids: 131Xe NMR
36.9 Metal-Organic Framework (MOF)
36.9.1 Non-flexible MOFs
36.9.2 Flexible MOFs
36.10 Carbon Materials
36.11 Heterogeneous Catalysis
36.11.1 Chemical Properties of Some Solid Catalysts
36.11.2 Chemical Kinetics
36.11.3 Diffusion
36.12 Theory: Modeling of Xenon Adsorption, Diffusion and Chemical Shift
36.12.1 Xe Atom-Surface Interaction, δa
36.12.2 Lennard-Jones Potential Curves
36.12.3 Other Modelings
36.13 Conclusion
36.14 Symbols
References
37 Magnetic Resonance Imaging (MRI)
37.1 Introduction
37.2 The MRI Technique
37.3 Homogeneous Versus Heterogeneous Catalysis
37.4 MRI/MRS of Operating Catalysts and Reactors
37.4.1 Liquid-Solid Processes
37.4.2 Gas-Liquid-Solid Processes
37.4.3 Gas-Solid Processes
37.4.4 Signal Enhancement in Reactions Involving H2
37.5 MRI Thermometry of Operating Catalysts and Reactors
37.6 Conclusions and Outlook
References
38 Electron Paramagnetic Resonance (EPR)
38.1 Introduction
38.1.1 Theory
38.1.2 Hardware
38.1.3 Data Analysis
38.2 Strategies for In Situ EPR Studies
38.2.1 Spin Trapping
38.2.2 Spin Labeling and Isotopic Substitution
38.2.3 Metals and Free Radicals
38.2.4 Electrochemistry and EPR
38.3 The Future of In Situ EPR
References
39 Case Studies: Time-Resolved Electron Paramagnetic Resonance (EPR)
39.1 Introduction
39.2 Opportunities and Challenges in In Situ EPR of Transition Metal Centers
39.3 Information from Analysis of EPR Spectra
39.4 Information from Time-Resolved EPR Spectral Intensity During In Situ Measurements
39.4.1 Cu-Zeolite
39.4.2 Vanadium in a Keggin-Type Polyoxometalate on Titania
39.5 Discussion
39.6 Conclusion
References
Part VII: Transient and Thermal Methods
40 Temporal Analysis of Product (TAP)
40.1 Introduction
40.2 Basic Experimental Concepts
40.2.1 Instrument Configuration
40.2.2 Experimental Concepts, Distinctions
40.3 Theoretical Tools for Extracting Kinetic Information from the Pulse Response
40.3.1 Collisions in a Diffusion Reactor
40.3.2 Reactor Transport: The Standard Diffusion Curve
Active Zone Configurations
Uniformity of the Gas and Solid in the Kinetic Measurement
40.3.3 Numerical Solution to Diffusion/Reaction Systems
40.3.4 Model-Free Analysis of Pulse Response Data
Primary Analysis: Moment-Based Quantities
Shekhtman Reactivities
Time-Dependent Analysis of Rate and Concentration
40.4 Experimental Studies of TAP Catalyst Characterization
40.4.1 Coverage-Dependent Sticking Coefficients
40.4.2 Active Site Titration at Working Temperatures
Titrating Sites with Irreversibly Adsorbing Species
Screening Multiple Active Site Mixtures
Heat of Adsorption, Counting Sites Where Adsorption Is Reversible
40.4.3 Mechanistic Features
Adsorption Mechanism
Competitive and Inhibited Adsorption
Mars van Krevelen Mechanism
General Reaction Model Analysis
40.4.4 Role of Dynamic Surface Species in Reaction Mechanism, Lifetime of Fast Surface Intermediates
40.4.5 The Pressure Gap
40.5 Conclusion
References
41 Steady-State Isotopic Transient Kinetic Analysis (SSITKA)
41.1 Introduction
41.2 SSITKA Principle
41.3 SSITKA Modeling
41.3.1 Single Pool First-Order Irreversible Reaction
41.3.2 Multiple Pools in Series for a First-Order Irreversible Reaction
41.3.3 Multiple Pools in Parallel for a First-Order Irreversible Reaction
41.3.4 Reversible Reactions
41.4 Complicating Factors
41.4.1 Gas Phase Hold-Up, Readsorption, and Chromatographic Effect
41.5 Reactivity Distributions
41.5.1 Fitting to Exponential Functions (Parametric Approach)
41.5.2 Inverse Laplace Transform (ILT) Method
41.5.3 Tikhonov-Fredholm (T-F) Method
41.6 Reactors and Isotope Effects
41.7 Experimental Setup
41.8 Combination of SSITKA with Spectroscopic Methods
41.8.1 SSITKA-FTIR
41.8.2 SSITKA-Neutron Scattering
41.9 Other Considerations and Recent Developments
41.10 Applications
41.10.1 Discriminate Between Different Reaction Mechanisms
41.11 Examples of the Use of SSITKA
41.11.1 CO Hydrogenation on Al2O3-Supported Co Catalysts
41.11.2 The Use of Multicomponent SSITKA to Obtain Kinetic Parameters for Higher Hydrocarbons in CO Hydrogenation [8]
41.11.3 Surface Species and Mechanistic Studies by Combination of SSITKA and Kinetic Isotope Effect
41.11.4 Combing DFT and Transient and Steady-State Modeling to Study Reaction Mechanism of CO Hydrogenation
41.12 Examples of Combining SSITKA-DRIFT for WGS
41.13 Further Reading
References
42 Modulation Excitation Spectroscopy (MES)
42.1 Introduction
42.2 Modulation and Phase-Sensitive Detection
42.3 Use and Interpretation of Phase-Resolved Data
42.4 Summary and Outlook
References
43 Case Study 1: Modulation Excitation Spectroscopy (MES)
43.1 Introduction
43.2 State-of-the-Art Spectroscopic Studies on Selective Catalytic Reduction
43.3 Beyond the Steady-State: Advantages of Modulated Excitation
43.3.1 Amplification of Weak Signals and Resolution of Peaks
43.3.2 Discrimination Between Active and Responsive Sites
43.3.3 Detection of Intermediates Species
43.4 Considerations on the Selection of Modulation Experiment
43.5 Summary
References
44 Case Study 2: Modulation Excitation Spectroscopy (MES)
44.1 Introduction
44.1.1 Biocatalyzed Kinetic Resolution of Racemic Profens with Lipases
44.1.2 Mechanism of the Enzymatic Kinetic Resolution of Racemic Profens
44.1.3 Experimental Evidences of the Acyl-Enzyme Intermediate
44.2 Experimental Setup
44.2.1 Materials
44.2.2 Attenuate Total Reflection Infrared Spectroscopy
44.2.3 Isotopic Exchange H-D of the Enzymes with D2O
44.2.4 MES Experiments
44.2.5 MCR-ALS Procedure
44.3 Results
44.3.1 Effect of the Nature of the Liquid Environment in the Secondary Structure of Lipases
44.3.2 MES-PSD Approach for the Molecular Recognition of an Acyl-Enzyme Intermediate
44.4 Conclusions and Future Perspectives
References
45 Temperature-Programmed (TP) Techniques
45.1 Introduction
45.2 Description of Temperature-Programmed Methods
45.2.1 Theory
45.2.2 Benefits from Characterization of Catalysts
45.2.3 Limitations of Temperature-Programmed Techniques
45.2.4 Comparison of Method to Other Techniques
45.3 Description of Temperature-Programmed Instruments
45.3.1 Single Crystals
45.3.2 Powders
45.3.3 History
45.4 Applications to Catalyst Structure-Activity Relationships: Methods and Case Studies
45.4.1 Thermogravimetric Analysis (TGA) and Differential Thermogravimetric Analysis (DTG)
45.4.2 Temperature-Programmed Decomposition
Thermal Decomposition of Silver Carbonate (Ag2CO3)
Thermal Decomposition of Ammonium Metavanadate (NH4VO3)
45.4.3 Temperature-Programmed Oxidation (TPO) and Differential TPO
45.4.4 Temperature-Programmed Reduction (TPR)
H2-TPR
CO-TPR
45.4.5 Temperature-Programmed Desorption (TPD)
NH3-TPD
O2-TPD
45.4.6 Temperature-Programmed Surface Reaction (TPSR)
Number and Types of Surface Sites (Ns)
Supported Metal Oxide Catalysts
Bulk Oxide Catalysts
Bulk V2O5
Bulk MoO3
Bulk Nb2O5
Bulk TeO2
Bulk Mixed Oxides
Bulk Fe2(MoO4)3 Mixed Oxide
Source of Oxygen Involved in Oxidation Reactions
Supported Metal Oxide Catalysts
Bulk Mixed Oxide Catalysts
Reaction Mechanisms
Water-Gas Shift (WGS) Reaction (CO + H2O H2 + CO2)
Selective Oxidation of C3H6 to C3H4O (Acrolein)
Selective Catalytic Reduction (SCR) of NO with NH3
45.5 Summary/Conclusion/Future Outlook
References
46 Calorimetry Techniques
46.1 Introduction
46.1.1 Operation Modes in Calorimetry
Temperature Range
Measurement Under Pressure
Heating Rate
Effective Sample Volume
Sensitivity
46.1.2 General Calorimetry Applications
Specific Heat Measurements
Measurement of Reaction Heats
46.1.3 Measurement of Heats of Interactions
46.2 Differential Scanning Calorimetry (DSC)
46.2.1 Heat Flux DSC
46.2.2 Power Compensated DSC
46.2.3 Calvet DSC
46.2.4 Catalytic Applications of DSC and Coupled DSC/TGA Unit
46.3 Calorimetry-Volumetry (Gas Adsorption Calorimetry)
46.4 Liquid Phase Calorimetry
46.4.1 Titration Calorimetry
Determination of Effective Acid-Base Properties
Determination of Heat of Adsorption
46.4.2 Immersion Calorimetry
46.4.3 Reaction Calorimetry
Isothermal Reaction Calorimeters
Heat-Flow Reaction Calorimeter
Heat-Balance Reaction Calorimeter
Power-Compensation Reaction Calorimeter
Peltier Reaction Calorimeter
Isoperibolic Differential Reaction Calorimeter
46.5 Single Crystal Adsorption Calorimetry (SCAC)
46.6 Conclusions
References
47 Case Study: Calorimetry
47.1 Introduction
47.2 Strength and Surface Density of Acid/Base Sites
47.3 Interaction of Reactants with the Surface
47.4 Turnover Frequencies
47.5 Transient Catalyst Behavior
47.6 Elucidating a Reaction Mechanism
47.7 Summary
References
Part VIII: Soft Operando
48 Chemometrics and Process Control
48.1 Why Chemometrics?
48.2 Mechanistic Methods
48.2.1 Basics of Mechanistic Methods
48.2.2 Workflow of Peak Integration
Case 1: Carbonate Selectivity in CO2 Utilization
48.2.3 Workflow of Spectral Hard Modeling
Case 2: Continuous Lithiation Reaction
48.2.4 Workflow of Univariate Calibration
Case 2: Continued
48.3 Statistical Methods
48.3.1 Basics of Statistical Methods
48.3.2 Workflow of PLS Calibration
Case 3: Nutrients, Metabolites, and Cell Parameters in Mammalian Cell Culture
48.4 Conclusion
References
Index