Plasmonic noble metal doped titanium dioxide nanocomposites: Newer and exciting materials in the remediation of water contaminated with micropollutants

The noble metal nanoparticles doped semiconductor titanium dioxide have received greater attention and showed enhanced applicability and utility in the diverse field of research. Applications of these materials in the environmental sciences, specifically in the decontamination of aquatic environments contaminated with various micropollutants, is an emerging area of research. These materials have shown promising features that attracted global interest. The noble metals viz., Au, Ag, Pt, and Pd are extensively included in the review article for their use removing of various micropollutants contaminating the aquatic environment. Synthesis and characterization of these materials are essential for their insightful understanding of remediation processes. Various preparatory methods of materials and their photocatalytic efficiency, along with the mechanistic aspects, are critically evaluated in the review. The critical components of the catalyst for possible implications are the materials' shape, size, textural distribution, loaded amount of noble metal nanoparticles, and the band gap energy of materials. Further, the role of the light sources in photocatalytic operations is crucial and better optimized for greater output. Moreover, the practical aspects of these materials are extensively studied for their stability/reusability in prolonged operations, selectivity for real implications, and large-scale/or pilot-scale implications. Insights into the catalytic processes, particularly the radical identification, by-products formed, and reaction pathways, provide a more profound and molecular-level understanding of the processes. These input results pave the way for implementing the laboratory trials toward possible technology developments.