Sonocatalysis and sonophotocatalysis

This conference plenary will debate recent advances in the employment of sonolysis to design tailored materials and the power of sonocatalytic and sonophotocatalytic processes for water remediation. In a polluted and energy-hungry world, photocatalysis plays a key role in pollution remediation and energy conversion. In this context, ultrasound is an invaluable tool to tailor the synthesis of photocatalysts and to boost catalytic activity by process intensification. Today, exploration of the ultrasonic power in the catalytic synthesis of innovative (nano)-materials and chemical products at the lab and large scale has become a research hotspot. Many research studies reported that ultrasonic synthesis was the key factor in controlling some specific properties of materials, such as the size of nanoparticles, structure, interface interactions, porosity, and so on. On the other hand, sonolysis generates reactive oxygen species (ROSs) in liquid bulk by applying varying ultrasound frequency. Sonolysis has been widely applied to oxidize a wide range of organic pollutants and deactivate microorganisms. Recently, ultrasonic technology has been combined with several other methods for enhanced water remediation. One of the most successful approaches is sono-photocatalysis, which exhibits several advantages such as synergetic generation of ROSs upon simultaneous utilization of ultrasound and light, enhanced mineralization of toxic by-products, and continuous cleaning of the photocatalyst surface delaying deactivation. Several research studies have been reported on optimizing operating factors and engineering sono-photocatalytic reactors. In this presentation, our laboratory’s progress in the development of better (sono)photocatalytic materials and processes will be discussed. Specifically, this talk will focus on the role of ultrasound in tuning the physico-chemical features of oxide-based photocatalysts and their efficiency in hybrid advanced oxidation processes for emerging pollutant degradation. The key role of the (sono)photocatalyst morphological features will be discussed, also with respect to piezo-enhanced photocatalytic strategies. Overall, it is shown that ultrasound technology can offer promise for more efficient photocatalytic materials and hybrid processes with potential applications extending also to energy conversion.