Graphene-Based Hybrid Photocatalysts for Environmental Remediation

Globally accelerated industrialization and manufacturing have caused substantial concerns over the advancement of environmental sanitization technologies. Unacceptably high levels of organic and inorganic contaminants in the air, water, and soil are causing global concern. A new avenue for environmental remediation has opened up in recent years with the progressive emergence of two-dimensional (2D) nanomaterials as a series of promising materials in photocatalysis. As a result, graphene-based photocatalysts have emerged as one of the latest topics in photocatalysis of environmental contaminants and have been widely used in the degradation of environmental pollutants. Graphene is most frequently employed in conjunction with other semiconductor materials, where it slows down the rate of charge recombination by facilitating the rapid transit of produced photoelectrons to the conduction band. Given their extraordinary surface area, high adsorption capacity, and efficient photocatalytic properties, graphene-based hybrids are excellent adsorbents and photocatalysts that can capture the majority of pollutant molecules and retain them for photocatalytic degradation. On the other hand, when developing graphene-based hybrid photocatalysts, factors such as degree of oxidation to adjust electrical conductivity and to accommodate guest molecules, type of semiconductor involved and its doping to adjust the band gap, interfacial contact between the graphene and the semiconductor material, surface architecture, multijunction formation for extended electron–hole separation efficiency, and photostability should be taken into account to produce efficient photocatalytic activity. Along with the numerous benefits of graphene-based photocatalysts, there are also some significant drawbacks, such as their high cost, lack of reusability, and difficulty in generating consistent levels of oxidation during large-scale manufacturing. Additional work with sophisticated and optimized techniques is required to boost the potential of graphene-based hybrids as a valuable degradation medium. This chapter will focus on the specifics of designing factors for effective photocatalysis, the most recent graphene-based hybrid photocatalysts used in the degradation of widely available pollutants, detailing their advantages and limitations, and finally concluding with future perspectives for more advanced development of graphene-based photocatalytic hybrids.