Graphene-Based Photocatalysts for Air Purification

During the last few decades, air pollution has become a threat to environmental stability. Due to the industrial revolution, many gaseous pollutants such as NH3, NO2, and volatile organic compounds (VOCs) like aromatic, aliphatic, aldehyde, halogenated, and terpenoid compounds are commonly added to the air. Photocatalysis is one of the most emerging technologies for the eco-friendly degradation of environmental pollutants. Photocatalysis is based on harvesting natural sunlight, or ultraviolet (UV) light. The photocatalytic activity of a material depends upon chemical composition, surface area, size, and electronic properties. The 2D graphene due to its physicochemical, optical, and electrical properties, 2D semi-metallic possesses extensive applications in photocatalysis. The improved charge separation, wide band gap, reduced electron–hole pairs, enhanced surface area, and improved photocatalytic property have enabled the graphene to the destruction of environmental contaminants. Graphene in its different forms like graphene oxide, and reduced graphene oxide, when combined with other nanomaterials like semiconductors is reported for its outstanding photocatalytic degradation of inorganic and organic pollutants present in the air. For improved texture and surface, various approaches like doping with noble metals are employed. The oxygenic functional groups combine covalently and non-covalently to air pollutants, capture, convert, and remove harmful gases even during industrial processing. The photocatalytic role of graphene as the active sensor, and for control, conversion, removal, and reduction of harmful environmental gases has been a great concern for researchers. The current study will discuss the synthetic approaches, mechanism, success, and challenges for the graphene-based photodegradation of air pollutants.