Multifunctional Trimetallic Colloidal Plasmonic Nanohybrid: Highly Efficient Photocatalyst and Photothermal Agent

Herein, preparation of novel multimetallic core–satellite Pt-nanodots decorated TiO₂-coated AuNPs (AuNPs@TiO₂@Pt) plasmonic nanoparticles with well-defined spherical dendritic morphology and excellent colloidal stability are reported. The coating of a TiO₂ layer and PtNDs maximizes the surface plasmon resonance as there is a redshift from 525 to 550 nm and also increases surface area significantly. Prepared plasmonic nanohybrid is tested for multiple photosystems such as water pollutants (methylene blue, methyl orange, and methyl red) photodegradation at room temperature in visible light irradiation, and photothermal studies in near-infrared (NIR, 808 nm) light. AuNPs@TiO₂@Pt shows complete photocatalytic degradation of organic dyes (methylene blue = 40 min, methyl orange = 75 min, and methyl red = 60 min) at room temperature and the pseudo first-order rate constant is found to be 0.1242, 0.047, and 0.068 min⁻¹ for methylene blue, methyl orange, and methyl red degradation, respectively. Moreover, AuNPs@TiO₂@Pt also shows a high photothermal effect in NIR light irradiation with an excellent morphological and photostability.