Preface

The developments of defective photocatalysts have been considerably increased during the last few years to achieve the goal of new photoactive materials synthesis as an emerging research topic for interesting photocatalytic applications. Defect engineering in photocatalytic materials is a research area of great interest which has led to the preparation of highly effective photocatalysts for energy generation (i.e., water splitting for hydrogen production), environmental remediation (i.e., degradation of organic pollutants), and gaseous pollutants reduction (Figure 1.1). However, the challenge lies in precisely controlling the defects to achieve the desired modifications without introducing detrimental effects that could impede the overall performance of the utilized photocatalytic feedstocks. To fully harness the potential of defect engineering in photocatalysis, a multidisciplinary approach involving materials science, chemistry, physics, and engineering is required. Additionally, collaboration between theoretical and experimental scientists is a critical step to develop efficient photocatalytic materials and understand the underlying principles that govern their behavior. Nowadays, with continued research and development, the challenges associated with defect engineering should be addressed, which can result in advancements in sustainable energy production technologies and environmental remediation strategies. This book typically provides an overview of the principles and applications of defective photocatalytic materials in a clear and suitable manner. Additionally, this advanced book on defect-engineered materials can be a good reference for researchers, scientists, engineers, academics, etc., in the field of materials science, environmental engineering, and energy storage. The proposed book may provide deeper insights into the theoretical aspects of defect-engineered photocatalytic materials, discussing advanced techniques for their preparation and characterization, and furnishing detailed case studies and research findings in numerous photocatalytic applications. It assumes a certain level of background knowledge in chemistry, materials science, physics, etc. The effectiveness of photocatalysis processes in energy storage and environmental applications could be an excellent reason that this book can also attract researchers and industrialists in the fields of wastewater remediation, sterilization, desalination, gaseous pollutants degradation, as well as health care and energy conversion for useful chemicals production.

Figure 1 Defective inorganic and organic photocatalysts for catalytic transformations, environmental remediation and green fuels production.

Examples of defective photocatalytic materials are discussed in Chapter 1 by Labidi et al. They provided an overview of the concept of defects creation and formation in photocatalytic materials and the role of defects for the enhancement of their photocatalytic features. Theoretical modeling and their control utilizing various characterization techniques to study mechanisms of defect formation including band gap engineering, charge carrier separation and transfer, concentration of defects, defect-interface interactions, photostability, etc. Chapter 2 by Labidi et al. depicts the importance of defective photocatalytic materials synthesis and their usages in several domains. It also highlights the benefits and limitations of defect-engineered photocatalytic materials. Defect engineering as a method to customize the photocatalytic properties of titanium dioxide (TiO2) and other metal oxides (WO3, ZnO, etc.) is reviewed by Labidi et al. in Chapter 3. They presented the impact of defects on charge carrier dynamics, band structure, and reactivity of photocatalytic materials, highlighting the importance of defect control in enhancing light absorption, charge separation, and photocatalytic activity in numerous applications. Chapter 4 by Kumar and Rath furnishes an insight into the preparation methods and characterizations of defective heterojunction photocatalysts. It also highlights their photocatalytic applications and future perspectives with a focus on their advantages and disadvantages. Chapter 5 by Chen and Zhu provides an overview of defects creation and formation in metalorganic frameworks for numerous photocatalytic implementations. Defect engineering strategies in C3N4 include chemical modification, thermal treatments, and doping with other elements that enhance their photocatalytic performance by facilitating charge separation and improving their absorption of light for efficient photocatalytic applications are discussed by Gogoi et al. in Chapter 6. Chapter 7 by Elhleli and Moussaoui addresses the properties of defective graphene as photocatalysts with their advantages and disadvantages. They described defects created in graphene which can introduce mid-gap states, enabling the absorption of light across a wider range of wavelengths. This enhanced light absorption increases the efficiency of photocatalytic reactions. They outlined the defects as active sites for several photocatalytic reactions, facilitating the generation and separation of charge carriers, resulting in efficient electron-hole transfer, leading to improved photocatalytic performance of graphene-based photocatalysts. Chapter 8 by Sudirman highlights the usages of defective photocatalytic materials in various organic transformations, including C-C and C-X bond formation, C-H functionalization, and cross-coupling reactions. Chapter 9 by Luo et al. depicts the application of defective photocatalytic materials in phototherapy. Chapter 10 by Ren et al. provides a comprehensive overview of the principles and mechanisms of photocatalysis for sterilization. Subsequently, it presents an in-depth discussion on different types of defects in semiconductor materials and their impact on photocatalytic activity. They also highlight various defect engineering techniques, including doping, surface modification, and defect passivation, aimed at improving the sterilization performance of defective photocatalysts. The future developments of defect-engineered feedstocks to degrade organic matters such as nano- and micro-plastics in wastewater are reviewed in Chapter 11 by Jalilnejad et al. focusing on the advanced designing of defective photocatalytic materials to improve their efficiency for nano-/micro-plastics photodegradation and their transformation into value-added chemicals and fuels. Chapter 12 by Wu and Cui details the use of defective photocatalytic materials for enhancing desalination processes highlighting the importance of efficient salt removal and water purification by way of photocatalysis processes. Chapter 13 by Hu offers knowledge about the potential defective photocatalysts in wastewater treatment technologies. It will also provide information about their synthesis, characterization, and benefits in organic pollutants degradation. Tailoring defective photocatalytic materials to develop highly efficient and selective photoactive feedstocks for NOx remediation is reviewed comprehensively by Zhu et al. in Chapter 14 focusing on the efficiency of defective photocatalytic materials to achieve NOx reduction purposes and explaining the important role of defect formation in these feedstocks for highly efficient NOx remediation technologies. Chapter 15 by Pourshirband et al. presents the defect formation/creation in several photocatalytic feedstocks. In addition, it highlights the synthetic protocols and identification of these defective materials for biomass conversion technologies. Understanding the precise role of specific defects and optimizing the photocatalytic systems for practical CO2 conversion to value-added chemicals and fuels are discussed by Chen et al. in Chapter 16, presenting information about usages of defect-engineered materials and their benefits and limitations in CO2 conversion purposes. Exploring novel photocatalytic materials, optimizing defect structures, and developing new synthesis methods for defective photocatalysts are described by Sial et al. in Chapter 17, listing some examples of defective photocatalytic materials and describing their advantages and disadvantages for H2 evolution. Chapter 18 by Padervand et al. examines mechanisms involved in H2O2 production on defect-engineered photocatalysts and the factors influencing their catalytic performance. It further addresses the challenges and opportunities associated with defect engineering for H2O2 production, suggesting future research directions in this area of research interest. The synthesis of ammonia (NH3) through photocatalytic processes using defect-engineered photocatalytic materials is deeply discussed by Li et al. in Chapter 19 with understanding the role of defects in enhancing the performance of photocatalysts with the development of new strategies for optimizing NH3 synthesis processes. Chapter 20 by Sial et al. provides a comprehensive overview of defect engineering in photocatalytic materials, focusing on their structures, photoelectronic properties, and photocatalytic applications. It explores the role of defects in modifying the electronic structure and optical features of photocatalysts, and how these modifications can enhance their photocatalytic performance in numerous photocatalytic implementations.

Collectively, this cutting-edge book on defect-engineered materials is useful for exploring defective photocatalytic materials in numerous...