Graphitic Carbon Nitride as a Sustainable Photocatalyst Material for Pollutants Removal. State-of-the Art, Preliminary Tests and Application Perspectives

Photocatalysis is an attractive strategy for emerging pollutants remediation. Research towards the development of new, efficient and effective catalytic materials with high activity under wide irradiation spectra is a highly active sector in material science. Various semiconductor materials have been employed as photocatalysts, including TiO₂, SrTiO₃, CdS, BiVO₄, Ta₃N₅, TaON, Ag₃PO₄, and g-C₃N₄. The latter is a metal-free, low cost polymer, providing high adsorption and catalytic properties, shown to be promising for photocatalysis applications under visible light. Furthermore, g-C₃N₄ composites are among the most promising advanced photocatalytical materials that can be produced by green synthesis processes. In this paper, the state-of-the-art of g-C₃N₄ applications is reviewed, and application perspectives are discussed. Photocatalysis tests with g-C₃N₄ under Xenon irradiation were performed to gather first-hand information to improve photoreactor design. Xenon light spectrum appears to be a suitable radiation source to replace direct sunlight in engineered pollutants removal processes catalyzed by g-C₃N₄, in lieu of other currently used heterogeneous photocatalysis processes (e.g., TiO₂-UV). LED sources are also very promising due to higher energy efficiency and customizable, catalyzer-specific irradiation spectra.