The photocatalytic degradation of organic pollutants-a comprehensive overview

Abstract

Photocatalytic degradation is a promising and eco-friendly technology that effectively removes organic pollutants from both air and water. This process relies on light-activated semiconductor catalysts such as TiO₂, ZnO, CeO₂, g-C₃N₄, and various heterojunction composites. These materials generate highly reactive species, including hydroxyl radicals and superoxide anions, which are capable of breaking down persistent contaminants into harmless byproducts like carbon dioxide (CO₂) and water (H₂O). The efficiency of photocatalytic reactions is influenced by several factors, including the catalyst's composition, morphology, crystallinity, bandgap energy, surface area, light intensity, and wavelength. Operational conditions such as pH, contaminant concentration, and the presence of scavengers also play a significant role in determining the effectiveness of the process. Recent advancements in photocatalysis have focused on addressing challenges associated with conventional catalysts, such as limited response to visible light and fast recombination of charge carriers. Techniques such as surface modification, doping, the development of Z-scheme and S-scheme heterojunctions, and integration with carbon-based materials have been explored to enhance performance. This review provides an overview of the fundamental principles of photocatalysis, recent innovations in catalyst design, and the mechanisms involved in pollutant degradation. To translate this technology into practical, scalable solutions for reducing organic waste in the modern era, further interdisciplinary research and the development of cost-effective, visible-light-responsive, and durable photocatalysts are essential.