Photocatalytic degradation of gaseous benzene using metal oxide nanocomposites.

Rapid industrial growth has been accompanied by the pollution of hazardous volatile organic pollutants (VOCs) in air. Among various options available for the treatment of VOCs, the use of metal oxide composites as photocatalysts has been adopted preferably due to their potential to induce the synergistic interactions between the metal nanoparticles (NPs) and metal oxides (especially titanium dioxide (TiO2)). In this context, an in-depth review is offered to describe the fundamental mechanism of metal oxide-based photocatalysis for the oxidation of gaseous benzene as a model VOC. The discussion has been extended further to evaluate their performances in terms of key performance metrics (e.g., quantum yield (QY), space-time yield (STY), and figure of merit (FOM)). The TiO2-based metallic bi-component photocatalysts (e.g., Sr2CeO4/TiO2) generally exhibited better photodegradation efficiency with enhanced light absorption capability than monometallic-TiO2 (e.g., Pd-TiO2) composites or other modified photocatalysts (e.g., metal-organic framework (MOF)-based composites). Finally, we address the current challenges and future perspectives in this highly challenging research field.