Ultrasound Assisted (Photo) Piezocatalysis for Boosted Oxidation of Organic Pollutants: Fundamentals and Mechanisms

Solar photocatalysis is regarded as a clean and sustainable technology which can operate under solar light to generate reactive oxygen species (ROS). However, due to the heterogeneous nature, photocatalysis showed several technological problems such as weak mass transfer and photocatalyst deactivation. Ultrasonic assisted photo (piezo) catalytic process refers to the use of ultrasonic cavitation as external force to boost the generation of ROS and prevent the deactivation of the catalyst. This review aims to discuss the mechanistic pathways of photo (piezo) catalytic systems catalyzed by ultrasonic irradiation. The effect of microjets and shock waves plays a crucial role in maximizing the generation of ROS and activating the surface of the catalyst along with a significant improvement in mass transfer. In such a synergistic system, the mineralization of persistent organic pollutants (POPs) in water can effectively be achieved, leading to high water quality. Ultrasonic assisted catalysis for environmental remediation would be a sustainable tool and could solve several technology issues in photocatalysis, which might help to transfer this technology to real-world applications.