Photocatalysts for degradation of dyes in industrial effluents: Opportunities and challenges

Discharging dye contaminants into water is a major concern around the world. Among a variety of methods to treat dye-contaminated water, photocatalytic degradation has gained attention as a tool for treating the colored water. Herein, we review the recent advancements in photocatalysis for dye degradation in industrial effluents by categorizing photocatalyst materials into three generations. First generation photocatalysts are composed of single-component materials (e.g., TiO2, ZnO, and CdS), while second generation photocatalysts are composed of multiple components in a suspension (e.g., WO3/NiWO4, BiOI/ZnTiO3, and C3N4/Ag3VO4). Photocatalysts immobilized on solid substrates are regarded as third generation…