Iron oxides and hydroxides (Fe-OH) extracted from natural sources have garnered significant attention for their diverse catalytic applications. This article provides a comprehensive overview of the catalytic potential of naturally occurring Fe-OH, focusing on the influence of natural sources and preparation methods on their morphological characteristics and application in heterogeneous catalysis. The unique physicochemical properties of these catalysts, including their high surface area, redox activity, and tunable surface chemistry, make them promising candidates for various catalytic processes. The review discusses key catalytic reactions facilitated by natural Fe-OH, such as advanced oxidation processes (AOPs), electrochemical applications, catalytic cracking, and biodiesel production. Furthermore, it highlights recent advancements and challenges in utilizing these materials as heterogeneous catalysts. By presenting an analysis of the catalytic potential of natural iron oxides, this review aims to stimulate further research about the use of these materials, which are widely distributed in the Earth’s crust.

Heterogeneous Advanced Oxidation Processes (H-AOPs) are considered a new process for removing emerging pollutants. In this case, the high reactivity of hydroxyl radicals is used to degrade persistent organic pollutants. This review explores the state-of-the-art catalyst for hydroxyl radical generation in AOPs. As a parasite reaction, chloride ions appear in alkaline conditions and compete with the active sites. The theoretical foundation of catalyst performance is explored, focusing on the fundamental principles that govern the efficiency and mechanism of hydroxyl or chloride radical production. The synthesis and electronic modification sections explore the modifications of catalysts. It discusses key methodologies for catalyst preparation, with a particular emphasis on electronic modification that enhances both activity and stability. Finally, laboratory and pilot applications highlight the effectiveness of novel or modified catalysts in different scenarios. These last findings provide insights into the future directions for research and application, aiming to draw attention to the gap between laboratory studies and real-world implementations.

Given the variability of challenges cities and urban areas face today, including most profoundly inclusion, safety, and resilience, the objective of this chapter is to examine how generative artificial intelligence (GenAI) may facilitate the process of addressing these challenges, thus fostering sustainable cities. By focusing explicitly on smart cities, in this chapter, it is argued that a great variety of GenAI-based applications exist, and these may bear great value for smart cities and their inhabitants. Indeed, by now, GenAI and GenAI-based applications have proven useful in integrating and analyzing information, thereby facilitating operations such as analysis, data management, and description. Accordingly, when utilized in the smart city and/or urban context, GenAI is of value in relation to urban planning, disaster preparedness and mitigation, traffic management, public safety, waste management, and last but not least improving the efficiency and quality of services’ provision to the city inhabitants. Clearly, the use of GenAI in this context presents challenges too, including data timeliness, different representations, and other issues related to the complexity of urban data. These considerations should be considered in the design, development, and implementation of GenAI-based applications to ensure their effectiveness, accuracy, and compliance with regulatory frameworks as well as with values and principles. None of these is possible without an explicit engagement of human beings, i.e., experts, who would provide monitoring and oversight over the GenAI-devised suggestions and recommendations. <!----> <!----> <!----> <!---->