Sustainable synthesis of photocatalytic materials for dye degradation in water: recent advances, challenges, and future perspectives

The rising demand for clean water and growing prevalence of persistent organic contaminants have fueled the development of nanostructured photocatalysts for dye removal from contaminated water. Despite the substantial improvement of photocatalytic efficiency, traditional synthesis methods usually need the use of toxic chemicals, highly energy-intensive techniques, and nonrenewable resources, which are of concern in terms of environmental sustainability and scalability. Sustainable synthesis has thus become a potential method for combining the concepts of green chemistry with the development of high-performance photocatalytic materials. This review provides a comprehensive review of eco-friendly techniques for the synthesis of nanostructured photocatalysts, such as plant- and biomass-assisted synthesis, biological methods, as well as green-assisted hydrothermal, microwave, mechanochemical, and solvent-free synthesis approaches. The influence of these sustainable synthesis routes on the structural, optical, and surface properties of the photocatalysts, including crystallinity, morphology, defect engineering, specific surface area, and charge carrier dynamics, is discussed in relation to their photocatalytic performance for dye degradation and removal, with comparisons to conventionally synthesized materials were reported. The review also discusses recent breakthroughs, existing problems in terms of reproducibility, scale-up, and industrial implementation, as well as future perspectives on the development of cost-effective and environmentally friendly photocatalytic materials. This review seeks to summarize current findings on the design and development of nanostructured photocatalysts for dye removal from water by integrating sustainable material synthesis with photocatalytic treatment.