Graphitic Carbon Nitride-based New Advanced Materials for Photocatalytic Applications

Abstract

Background: The present scenario of rapid industrial and population growth has become a serious threat to environmental and energy concerns. Extremely noxious pollutants like dyes, heavy metal ions, phenols, antibiotics and pesticides in water are the reason behind deprived water quality leading to inadequate access to clean water. Photocatalysis is a prominent strategy for environmental remediation as photocatalytic materials not only convert solar energy into usable energy expedient but also shows potential application in pollutant mitigation. An effectual photocatalytic system must possess wide visible absorption range, high physio-chemical firmness, and effective space-charge separation along with strong redox ability. Polymeric graphitic carbon nitride a metal-free semiconductor photocatalyst has outshined as a robust photocatalyst for various photocatalytic applications. Methods: Hybridizing polymeric g-C3N4 with other semiconductor photocatalysts has not only conquer the limitations related to pristine g-C3N4 but also displayed improved photoactivity. Different photocatalytic systems involving g-C3N4 coupled metal-oxides, metal-free systems and complex heterojunction systems are reviewed. Moreover, an all-embracing study based on g-C3N4 based nanocatalysts is explored via heterojunction formation taking g-C3N4 as one component. Results: Photocatalytic experiments involving photodegradation of pollutants, revealed the significance of metal-free g-C3N4 in the heterojunction system which remarkably boost the photoactivity through effective separation and migration of photocarriers. Moreover, from recyclability experiments, exceptional photostability of g-C3N4 based photocatalysts was observed. Photocatalytic pollutant degradation is a complex phenomenon which requires significant experimental techniques to support the mechanism. With the help of photoelectrochemical analysis, the mechanisms behind photodegradation can be evaluated and explored. Conclusion: Metal-free polymeric g-C3N4 is a potential semiconductor photocatalyst which can be optimally utilized for wastewater treatment. Coupling g-C3N4 with another semiconductor material with an appropriate band edge can effectively enhance the photocatalytic efficacy. Herein, g-C3N4 derived metal-oxide, metal-free and complex heterojunction systems are explored and their photocatalytic efficiency is evaluated for pollutant degradation. However, more effective research efforts are needed for large-scale applications of g-C3N4 based photocatalysts.