Ultrasonic-assisted synthesis of solid acid catalysts: Mechanisms, efficacy, and industrial prospects

Abstract

Against the backdrop of increasingly severe global energy and environmental pressures, solid acid catalysts are attracting growing attention as greener alternatives to conventional liquid acids, owing to their ease of separation, lower corrosivity, reusability and reduced environmental impact. However, mainstream preparation routes still suffer from intrinsic limitations, such as insufficient density and non-uniform spatial distribution of acid sites, inadequate structural stability and suboptimal catalytic performance. Ultrasonic-assisted synthesis harnesses the transient high temperatures and pressures, intense micro-jets, shear fields and reactive radical species generated by acoustic cavitation to enhance the dispersion of active components, regulate the balance between Brønsted and Lewis acid sites and tailor pore architecture. These effects collectively improve acid loading efficiency, strengthen catalytic activity and extend catalyst lifetime. This review first summarizes the main types and preparation strategies of solid acid catalysts and analyzes the key challenges in their synthesis. It then focuses on the enhancement mechanisms and structural regulation effects of ultrasound in catalyst preparation, together with recent advances in the design and optimization of ultrasonic reactors. Finally, the prospects and critical issues for the industrial application of ultrasonic-assisted solid acid catalyst preparation are discussed, with the aim of providing a useful reference for translating ultrasonic technology from laboratory research to large-scale production.