Synthesis of Nanoparticles and Quantum Dots for Visible-Light Photocatalysis: TiO₂ and AgNPs

https://doi.org/10.5281/zenodo.18690977

Abstract

Visible-light-driven photocatalysis has emerged as a promising and sustainable approach for addressing environmental pollution and energy challenges. Among various photocatalytic materials, titanium dioxide (TiO₂) nanoparticles and silver nanoparticles (AgNPs), including quantum dots, have gained significant attention due to their unique physicochemical properties, high stability, and strong catalytic potential. This review comprehensively summarizes recent advances in the synthesis of TiO₂ nanoparticles, AgNPs, and their corresponding quantum dots with a focus on strategies that enhance visible-light activity. Conventional chemical and physical synthesis routes are discussed alongside green and bio-mediated approaches that offer eco-friendly and cost-effective alternatives. The review further highlights band-gap engineering, metal and non-metal doping, surface modification, and heterojunction formation as key methods to improve light absorption and charge separation under visible-light irradiation. Applications of TiO₂- and AgNP-based photocatalysts in wastewater treatment, degradation of organic pollutants, antimicrobial activity, and renewable energy generation are critically analyzed. Finally, current challenges, limitations, and future perspectives are outlined to guide the rational design of efficient, stable, and environmentally benign photocatalysts for next-generation visible-light applications.