Nanostructured TiO2 E-Book
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- Herausgeber: Wiley-VCH
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Comprehensive reference on TiO2 materials, from fundamentals to widely used areas such as water purification and solar fuel generation
With in-depth analysis and coverage, Nanostructured TiO2 is an advanced reference on the subject, offering techniques, characterizations, and novel approaches to titanium dioxide (TiO2) nanostructures. The book incorporates cutting-edge research findings and innovations in the synthesis and utilization of TiO2 nanostructures.
From environmental remediation and renewable energy to biomedical applications and advanced materials science, this book provides insights into how these materials are transforming a wide range of industries. In addition to theory and research, the book provides practical insights including real-world case studies, experimental protocols, and problem-solving techniques.
Nanostructured TiO2 includes information on:
- Controllable synthesis of zero- to three-dimensional TiO2 nanostructures, immobilization of TiO2 on various substrates, and surface modification of TiO2
- Photocatalytic fixed-bed reactions for efficient photon utilization of TiO2 and carrier transport and recombination in sensitized nanostructured TiO2
- Type, characterization, and activity of TiO2-based heterojunction photocatalysts
- Application of TiO2 for the photocatalytic conversion of nitrogen oxides NO and NO2
- Recycling of heavy metal ions from wastewater by TiO2 photocatalysis
Nanostructured TiO2 is an essential up-to-date reference for inorganic chemists, catalytic chemists, materials scientists, photochemists, and professionals in the sensor industry seeking state-of-the-art knowledge on the subject.
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Veröffentlichungsjahr: 2025
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Table of Contents
Cover
Table of Contents
Title Page
Copyright
Introduction: Overview of
Nanostructured TiO
2
: Synthesis, Properties, and Photocatalytic Applications
Acknowledgments
Part I: Synthetic Methodologies
Chapter 1: Selective Synthesis of TiO
2
Nanoparticles
1.1 Introduction
1.2 Synthesis of TiO
2
NPs by Sol–Gel Reaction Under Acidic Condition
1.3 Sol–Gel Reaction in Basic Condition
1.4 Shape Control with Capping Agent Under Neutral pH
1.5 Synthesis of Extremely Small TiO
2
NPs Using Dendrimer
References
Chapter 2: Synthesis of One-dimensional TiO
2
Nanomaterials
2.1 Introduction
2.2 TiO
2
NRs
2.3 TiO
2
NT Structure
2.4 TiO
2
NB
2.5 TiO
2
NFs by Electrospinning
2.6 NR or NW Arrays
References
Chapter 3: Synthesis of Two-dimensional TiO
2
Nanostructures
3.1 Introduction
3.2 Synthesis of 2D TiO
2
Nanostructure
3.3 Conclusion
References
Chapter 4: 3D TiO
2
via Self-assembly
4.1 Introduction
4.2 Template Method
4.3 Self-Template Route
4.4 3D Hierarchical Porous TiO
2
Spheres by Solvo/Hydrothermal Process
4.5 Conclusion
References
Chapter 5: Immobilization of TiO
2
on Various Substrates
5.1 Introduction
5.2 Immobilization Techniques
5.3 Techniques for Immobilizing TiO
2
on to Various Substrates
5.4 Electrospun/Organically Modified Montmorillonite Nanofibrous Membrane
5.5 Metal Oxide Substrates (Alumina, Silica, etc.)
5.6 Microplasma Printer for TiO
2
Deposition
5.7 Polymeric Substrates
5.8 Carbon-Based Substrates (Activated Carbon, Carbon Nanotubes, etc.)
5.9 Ceramic Substrates
5.10 Textile Substrates
5.11 Critical Parameters for TiO
2
Immobilization
5.12 TiO
2
-immobilized Biodegradable Polymers for Enhanced Photocatalytic Activity
5.13 Polymers (Natural and Biodegradable)
5.14 Future Perspective and Discussions
5.15 Conclusion
References
Chapter 6: Surface Modification of TiO
2
6.1 Introduction
6.2 General Strategies of Surface Modification
6.3 New Direction of TiO
2
Modification
6.4 Conclusion
Acknowledgments
References
Part II: Photocatalytic Properties
Chapter 7: Photocatalytic Fixed Bed Reactions for Efficient Photon Utilization of TiO
2
7.1 Introduction
7.2 Cognition of Time Consumption for Photoinduced Electronic Processes
7.3 Immobilized Pt/TiO
2
Photocatalyst
7.4 Configuration Features of Immobilized TiO
2
|Pt Photocatalyst for Efficient PFBR
7.5 Applications of PFBR
7.6 Conclusion
Acknowledgments
References
Chapter 8: Carrier Transport and Recombination in Sensitized Nanostructured TiO
2
8.1 Introduction
8.2 Overview of SSCs
8.3 Fundamentals of Carrier Transport and Recombination in Sensitized TiO
2
8.4 Conclusion
References
Chapter 9: TiO
2
-based Heterojunction Photocatalysts: Type, Characterization, and Activity
9.1 Introduction
9.2 Classification of Heterojunction
9.3 Characterization Technologies of S-scheme Heterojunction
9.4 Roles of Heterojunctions
9.5 Conclusion
References
Chapter 10: Plasmonic Metal–TiO
2
Photocatalysts
10.1 Surface Plasmon Resonance
10.2 The Enhanced Photocatalytic Mechanism Based on LSPR
10.3 The Strategies for Synthesis of Plasmonic Metal–TiO
2
Nanocomposites
10.4 Applications of Plasmonic Metal–TiO
2
Photocatalysts
10.5 Summary
References
Chapter 11: Ecotoxicological and Antibacterial Assessment of Nanostructured TiO
2
11.1 Introduction
11.2 Ecotoxicological Effects of TiO
2
11.3 The Antimicrobial Properties of TiO
2
11.4 The Impact of TiO
2
on Health
11.5 The Medical Potential of TiO
2
11.6 The Use of Environment Friendly TiO
2
11.7 Conclusion
References
Part III: Applications
Chapter 12: Applications of TiO
2
for Photocatalytic Water Treatment
12.1 Introduction
12.2 Photodegradation Mechanism
12.3 Research on Modified TiO
2
Catalysts for Water Purification
12.4 Photocatalytic Reactor Design
12.5 Kinetic Analysis
12.6 Challenges and Perspectives
12.7 Conclusion
References
Chapter 13: TiO
2
Photocatalytic Degradation of Antibiotics
13.1 Introduction
13.2 Performance and Mechanism of TiO
2
Photocatalytic Degradation of Antibiotics
13.3 Modification of TiO
2
to Enhance the Efficiency of Antibiotic Photocatalytic Degradation
13.4 Factors Influencing the Antibiotic Degradation Efficiency and the Underlying Mechanisms
13.5 Photocatalysis Coupled with Other Technologies to Enhance the Efficiency of Antibiotic Degradation
13.6 Summary
References
Chapter 14: Ecotoxicological and Antibacterial Properties of TiO
2
and Processes Based on TiO
2
14.1 Introduction
14.2 Species Commonly Used in Ecotoxicity Tests
14.3 TiO
2
Particles Ecotoxic Impact
14.4 Ecotoxicity from Wastewater Treated by Photocatalytic Processes with TiO
2
14.5 Antibacterial Properties of TiO
2
-based Photocatalytic Processes
14.6 Conclusion
References
Chapter 15: The Application of TiO
2
for the Photocatalytic Conversion of the Nitrogen Oxides – NO and NO
2
15.1 Introduction
15.2 Mechanism and ISO Protocol
15.3 Field Trials
15.4 Materials Design
15.5 Challenges and Perspectives
List of Abbreviations
References
Notes
Chapter 16: Recycling of Heavy Metal Ions from Wastewater by TiO
2
Photocatalysis
16.1 Introduction
16.2 Mechanism of Photocatalytic Reduction Recovery
16.3 Photocatalytic Treatment of Cu(II), Cr(VI), U(VI), and As(III/IV) by TiO
2
16.4 Conclusions and Outlook
References
Chapter 17: Solar Fuel Generation
17.1 Introduction to the Solar Fuel Generation Using Nanostructured TiO
2
17.2 Solar Energy: Hydrogen Production
17.3 Solar Fuel: Carbonaceous Solar Fuels from CO
2
17.4 Solar Fuel: Ammonia from N
2
17.5 Summary
References
Chapter 18: Visible-light-induced Selective Oxidation of Organic Molecules over Nanostructured TiO
2
18.1 Introduction
18.2 Visible-light-induced Selective Oxidation of Organic Molecules
18.3 Summary and Outlook
Acknowledgments
References
Chapter 19: Photoelectrochemical Sensing Applications of Nanostructured TiO
2
19.1 Introduction
19.2 Fundamentals of PEC Sensing
19.3 PEC Detection of Biomolecules
19.4 PEC Detection of Harmful Ions
19.5 PEC Detection of Organic Pollutants and Oxygen Demand
19.6 Conclusion
References
Chapter 20: Reactor Engineering in Competitive Photocatalytic Performance: Advancements and Challenges
20.1 Brief Overview
20.2 Photoreactor Architecture
20.3 Main Applications of TiO
2
in Photocatalytic Reactors
20.4 Conclusion
Acknowledgments
References
Chapter 21: TiO
2
-based Protective Coatings for Buildings and Monuments
21.1 Introduction
21.2 TiO
2
-based Protective Coatings
21.3 Summary and Outlook
Acknowledgments
References
Index
End User License Agreement
List of Tables
Introduction
Table 1 Crystal structures of four TiO
2
polymorphs: anatase, rutile, brookite, and TiO
2
...
Chapter 6
Table 6.1 Representative works of TiO
2
modification with noble metal nanoparticles
Chapter 12
Table 12.1 Photocatalytic degradation efficiencies of TiO
2
and doped TiO
2
materials for var...
Chapter 13
Table 13.1 Summary of recent studies employing TiO
2
-based photocatalysts for the degradatio...
Table 13.2 Summary of recent studies employing TiO
2
-based photocatalysts for the degradatio...
Table 13.3 Summary of recent studies employing TiO
2
-based photocatalysts for the degradatio...
Table 13.4 Summary of recent studies employing TiO
2
-based photocatalysts for the degradatio...
Table 13.5 Summary of recent studies employing TiO
2
-based photocatalysts for the degradatio...
Table 13.6 Summary of recent studies employing TiO
2
-based photocatalysts for the degradatio...
Chapter 14
Table 14.1 Species commonly used for toxicological bioassays.
Chapter 15
Table 15.1 A summary of the performances of select examples of TiO
2
-based concrete, paint, ...
Chapter 16
Table 16.1 The recovery of copper by different types of acid and washing time. [15]/with pe...
Table 16.2 The mechanism of photocatalytic reduction of hexavalent uranium. [84]/with permi...
Guide
Cover
Table of Contents
Title Page
Copyright
Introduction: Overview of
Nanostructured TiO
2
: Synthesis, Properties, and Photocatalytic Applications
Acknowledgments
Begin Reading
Index
End User License Agreement
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Nanostructured TiO2
Synthesis, Photocatalytic Properties, and Applications
Edited by
Jia Hong Pan
Guangxi University
Wan In Lee
Inha University
Detlef W. Bahnemann
St. Petersburg University
Edited By:
Prof. Jia Hong Pan
School of Resources, Environment and Materials
Guangxi University
100 East Daxue Road
Xixiangtang District, Nanning, 530004
Guangxi Zhuang Autonomous Region
People’s Republic of China
Prof. Wan In Lee
Department of Chemistry and Chemical Engineering
Inha University
100 Inha-ro, Michuhol-gu
Incheon, 22212
Republic of Korea
Prof. Detlef W. Bahnemann
Photoactive Nanocomposite Materials Laboratory
V.A. Fock Institute of Physics
St. Petersburg University
Ulyanovskaya street 1, Peterhof, Saint Petersburg, 198504
Russia
Cover Design: Wiley
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Print ISBN: 9783527354177
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IntroductionOverview of Nanostructured TiO2: Synthesis, Properties, and Photocatalytic Applications
Jia Hong Pan,1,*Wan In Lee,2 Detlef W. Bahenmann,3,4
1State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures, School of Resources, Environment and Materials, Guangxi University, Nanning, Guangxi, China
2Department of Chemistry and Chemical Engineering, Inha University, Incheon, Korea
3Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Hannover, Germany
4Laboratory “Photoactive Nanocomposite Materials”, Saint Petersburg State University, Peterhof, Saint Petersburg, Russia
* To whom all correspondence should be addressed.
E-mail: [email protected] (J. H. Pan)
1 TiO2 Photocatalysis
The Sun emits heat and radiant light to Earth, serving as the most abundant renewable energy resource. Natural photosynthesis is a well-known photochemical process that directly or indirectly powers living organisms in the biosphere by converting solar energy into storable chemical energy. Inspired by this process, heterogeneous photocatalysis mediated by semiconductors has gained significant attention for its potential in efficient solar-to-chemical energy conversion, attracting ongoing interest and research.
TiO2 is a highly stable inorganic material that is comparatively abundant in the Earth’s crust. Known as a versatile and eco-friendly material due to its inert and non-toxic properties, TiO2 is widely used in our daily lives or industries as an additive in pigments, paints, toothpastes, sun creams, abrasives, pharmaceutical products, and other applications. Since Honda and Fujishima reported photocatalytic water splitting using TiO2 electrodes in 1972 [1], TiO2 has been intensively and extensively investigated as a photocatalytic material in various oxidation and reduction reactions. Although various inorganic, organic, and organic–inorganic hybrid semiconductors have been reported, TiO2 remains the most extensively studied photocatalyst to date because of its exceptional physicochemical properties, including low cost, high quantum efficiency, chemical and photonic stability, favorable band positions, non-toxicity, biocompatibility, and versatility in (photo)catalysis, optoelectronics, sensors, photovoltaics, and biomedical applications.
Figure 1 illustrates the charge carrier generation, trapping, recombination, and interfacial charge transfer during the TiO2 photocatalysis [2–4]. The process starts with the absorption of photons that possess energy greater than its bandgap. TiO2 is thus photoexcited, inducing interband transitions and generating electrons (e−) at the conduction band (CB) and holes (h+) at the valence band (VB). A large portion of the photogenerated e−/h+ pairs is susceptible to recombination within the bulk or TiO2 surface, resulting in the energy release as light and heat. On the other hand, free charge carriers without recombination can migrate and be trapped at the TiO2 surface independently. Upon interfacial charge transfer, the trapped e− and h+ enable the reduction and oxidation processes, respectively. The underlying reaction can be written as follows [3].
Figure 1 Charge carrier transfer during TiO2 photocatalysis. Adapted from Ref. 2 with permission from Elsevier.
Charge carrier generation:
Charge carrier trapping:
Charge carrier recombination:
Interfacial charge transfer with acceptor (A) or donor (D) molecules absorbed on the TiO
2
surface:
Optimizing the textural properties of TiO2 is critical for enhancing its photochemical performance, prompting sustained research interest in the manipulation of TiO2 nanostructures. Advancements in nanotechnology, particularly in nanomaterial synthesis, have facilitated diverse strategies for tailoring the properties of nanostructured TiO2. Moreover, various photocatalytic applications of TiO2 have been developed through the manipulation of electrons (e−), holes (h+), and their associated radicals.
2 Crystal Phase of TiO2
TiO2 possesses four main crystal phases, i.e., anatase, rutile, brookite, and TiO2(B), as summarized in Table 1 [5]. Depending on the polymorph, size, and pH, the potential of holes generated from TiO2 is +1.0 to +3.5 V vs. NHE, while those of electrons are 0.5 to −1.5 V vs. NHE [3, 4]. Anatase and rutile have a tetragonal structure with band gaps of 3.2 and 3.0 eV, respectively, while brookite has an orthorhombic structure with a band gap of 2.96 eV. Rutile is the thermodynamically most stable phase, which is formed above 600 °C, while anatase is a kinetically favorable phase at lower temperatures, and brookite is a metastable phase that often forms at around 500 °C. Monoclinic TiO2(B) is generally obtained from the proton exchange of alkaline metal titanates to H2TiO3, following a heat treatment at 300–450 °C to induce a phase transformation to TiO2(B). Unlike the three other key natural polymorphic forms, artificial TiO2(B) exhibits perovskite-like layered structure.
Table 1 Crystal structures of four TiO2 polymorphs: anatase, rutile, brookite, and TiO2 (B). Red balls and grey balls are representatives of O and Ti atoms, respectively, and the bright-blue space-filling polyhedron units present octahedral unit constructs from a Ti4+ ion and six O2− ions. Adapted from Ref. 5 with permission from Elsevier.
TiO
2
phase
Anatase
Rutile
Brookite
TiO
2
(B)
Space group
Band gap
3.2 eV
3.0 eV
3.0 eV
3.4 eV
Crystal structure
Polyhedral structure
In semiconductor photocatalysis, anatase is the most widely studied polymorph, showing superior photochemical performances owing to its high electron mobility, electron affinity, and transmittance for visible light. Rutile TiO2 exhibits relatively low photocatalytic activity. However, under visible light irradiation, rutile with a narrower bandgap might deliver better photocatalytic performances. When designing sunlight-active photocatalysts, the coexistence of anatase and rutile phases in nanostructured TiO2 can significantly enhance solar energy harvesting. This is the principle behind Aeroxide® P25 TiO2, which predominantly contains anatase with a smaller proportion of rutile. Brookite is the least studied as a photocatalyst, mainly due to challenges in controlling phase purity. TiO2(B) is only active in the UV region and exhibits photocatalytic activity comparable to that of anatase.
3 Synthesis of Nanostructured TiO2
A nanostructure refers to a material or object characterized by structural features at the nanoscale, typically with at least one dimension ranging from 1 to 100 nm. This nanoscale confinement imparts a high surface-to-volume ratio to the resulting nanomaterials, significantly enhancing their physicochemical properties and performance compared to bulk materials. Nanostructures can be categorized into four major types based on the degree of spatial confinement:
Zero-dimensional (0D) nanostructures: All dimensions are on the nanometer scale (e.g., nanoparticles).
One-dimensional (1D) nanostructures: One dimension is on the nanometer scale, while the other two are larger (e.g., nanorods, nanowires, and nanotubes).
Two-dimensional (2D) nanostructures: Two dimensions are on the nanometer scale, with the third being larger (e.g., nanosheets and nanoplates).
Three-dimensional (3D) nanostructures: Porous or hierarchical structures consisting of low-dimensional nanobuilding blocks (NBBs)
A variety of synthesis methods, including the sol-gel process, hydro/solvothermal techniques, and the combustion method, have been developed to enable the controllable fabrication of TiO2 nanomaterials in various forms of 0D nanoparticles (NPs), 1D nanorods, nanowires, and nanotubes, 2D nanosheets, and 3D superstructures, with variations in phases, dimensions, sizes, porosities, morphologies, and forms (e.g., powder, gel, film, and monolith). To the best of our knowledge, TiO2 has been the most frequently fabricated transition metal oxide over the past four decades, delivering an extremely rich gallery of TiO2 nanostructures.
Interestingly, in contrast to the abundance of TiO2 nanostructures, the precursors for synthesizing TiO2 nanostructures are quite limited, which include three key types:
Metallic Ti
Organic titanium alkoxide
Inorganic precursors: TiCl
4
, TiF
4
, Ti(SO
4
)
2
, or commercial TiO
2
Clearly, free Ti4+ ions seem to be absent in wet-chemical media where sol-gel process is frequently involved. Thus, deep understanding of the physicochemical properties of precursors and their chemical reactions is essential to the wet-chemical synthesis. Moreover, considerable interests have been attracted by the nucleation and growth mechanisms of TiO2 to reveal the formation of nanostructures. Therefore, Chapters 1–5 of this book systematically address the synthesis strategies of TiO2 of different dimensions, with a special focus on providing a fundamental insight into the underlying chemical reactions involved, and the accompanied growth models of TiO2 nuclei, with the ultimate goal of achieving a predictable synthesis of nanostructured TiO2 with controllable textural properties.
4 Photocatalytic Applications of Nanostructured TiO2
Continuous research aims to boost the photocatalytic efficiency of nanostructured TiO2-based photocatalysts, especially in the context of utilizing sunlight and improving their performance for large-scale applications. Photocatalytic applications of nanostructured TiO2 are vast and diverse, making them a critical material for addressing environmental and energy challenges, as comprehensively addressed in this book.
Environmental purification:
TiO
2
nanostructures are highly effective at degrading a wide range of organic pollutants in both atmospheric and aquatic ecosystems. Common atmospheric pollutants include volatile organic compounds (VOCs) and nitrogen oxides (NO
x
), while aquatic pollutants include dyes, pesticides, pharmaceuticals, and industrial chemicals. Under sunlight irradiation, photocatalytic oxidation of these contaminants can be conducted by the reactive oxygen species (ROS) generated by excited TiO
2
, breaking them down into harmless substances such as CO
2
and water. Additionally, TiO
2
is effective in killing bacteria and viruses in air and water, making it valuable for applications in medical devices, food packaging, and water treatment systems.
Solar fuel generation and chemical synthesis:
Nanostructured TiO
2
is widely used in photocatalytic water splitting to produce hydrogen. When exposed to UV light, TiO
2
generates electron–hole pairs that drive the water-splitting reaction, producing hydrogen gas as a clean energy source. TiO
2
nanostructures are also employed for photocatalytic CO
2
reduction, converting it into value-added chemicals such as CO, methane, or methanol. This process not only helps mitigate CO
2
emissions but also produces useful byproducts. Furthermore, TiO
2
is utilized in the photocatalytic synthesis of various organic compounds, offering a sustainable alternative to traditional chemical methods. These photocatalytic processes, including oxidation, reduction, and cross-coupling, operate under mild conditions without the use of harsh reagents or solvents.
Photocatalytic sensors and environmental monitoring:
TiO
2
-based photocatalytic sensors are used to detect pollutants, such as NO
x
and VOCs, in the environment. These sensors leverage the photocatalytic properties of TiO
2
to generate detectable signals in the presence of pollutants, providing real-time monitoring capabilities for environmental quality.
Self-cleaning coating:
TiO
2
-based photocatalytic coatings show self-cleaning properties when exposed to UV light. Organic dirt, oils, and pollutants on TiO
2
surfaces can be readily degraded or mineralized to maintain cleanliness without manual intervention, which is particularly useful for application in windows, solar panels, and building facades.
References
1
Fujishima, A. and Honda, K. (1972). Electrochemical photolysis of water at a semiconductor electrode.
Nature
238: 37–38.
2
Qian, R., Zong, H., Schneider, J. et al. (2019). Charge carrier trapping, recombination and transfer during TiO
2
photocatalysis: an overview.
Catalysis Today
335: 78–90.
3
Hoffmann, M.R., Martin, S.T., Choi, W., and Bahnemann, D.W. (1995). Environmental applications of semiconductor photocatalysis.
Chemical Reviews
95: 69–96.
4
Schneider, J., Matsuoka, M., Takeuchi, M. et al. (2014). Understanding TiO
2
photocatalysis: mechanisms and materials.
Chemical Reviews
114: 9919–9986.
5
Ding, Y., Yang, I.S., Li, Z.Q. et al. (2020). Nanoporous TiO
2
spheres with tailored textural properties: controllable synthesis, formation mechanism, and photochemical applications.
Progress in Materials Science
109: 100620.
Acknowledgments
We would like to express our deepest gratitude to the exceptional team at Wiley for their expertise, unwavering dedication, and invaluable support throughout the entire publication process. In particular, we extend our sincere thanks to Dr. Alice Qian, Elisha Benjamin, Sevanthi Vivekanandhan, and Dhanapriya Velumurthy for their meticulous attention to detail, tireless efforts, and commitment to ensuring the highest quality of presentation for this book. Their professionalism and dedication were pivotal in bringing this project to life.
We are also profoundly grateful to our colleagues and students, whose collaboration, insights, and encouragement have been indispensable over the years. This book would not have been possible without their collective contributions and support. We extend our heartfelt thanks to Yanjie Li and Shuangchao Tang for their invaluable assistance with reference management.
Finally, we would like to express our appreciation to everyone who contributed, directly or indirectly, to this work. Your dedication and support have made this journey truly rewarding.
Jia Hong Pan
Guangxi University, China
Wan In Lee
Inha University, Korea
Detlef W. Bahnemann
St. Petersburg University, Russia
Leibniz Universität Hannover, Germany
Shaanxi University of Science and Technology, China
