Photocatalytic Degradation of Organic Pollutants Using Advanced Semiconductor Materials

Abstract

Organic pollutants such as dyes, pesticides, pharmaceuticals and industrial chemicals persist in water and resist conventional treatment, creating a need for efficient and sustainable remediation technologies. Semiconductor photocatalysis uses light-generated electron-hole pairs to produce reactive oxygen species that degrade and ultimately mineralise these contaminants. This article reviews the fundamental principles and mechanisms of photocatalysis, benchmark materials such as titanium dioxide and zinc oxide, and advanced visible-light systems including graphitic carbon nitride, bismuth-based compounds and metal sulfides. Strategies for improving performance, namely doping, defect engineering, heterojunction construction and composite formation, are discussed together with the influence of operating parameters and kinetics. Applications to real water matrices, reactor design, catalyst stability and potential toxicity of by-products are examined. Remaining challenges and research directions are outlined to support the development of practical, solar-driven treatment technologies.