A review on the integration of ultrasonication in hybrid systems for enhanced hydrogen yield.

This review synthesizes recent developments in ultrasonication (US)/assisted and US/hybrid processes for hydrogen generation, with a focus on US/electrochemical techniques. It summarizes recent findings, discusses existing constraints, and suggests promising routes for further advancement. US/hybrid processes, including US/electrocatalytic techniques and other US-assisted methods, show great promise in improving efficiency and reducing the energy needed for hydrogen generation. The paper emphasizes how ultrasonication can accelerate electrochemical processes, improve mass transfer, and reduce overpotentials. Ultrasonication enhances the physical and chemical parameters of US/electrocatalytic processes by decreasing cell voltage and overpotentials while boosting overall energy efficiency. Other ultrasonication hybrid processes, such as sonocatalysis and US/photocatalysis, have demonstrated the potential to use ultrasonication to activate catalysts and increase hydrogen yields. Notwithstanding these progresses, difficulties remain, such as improving the understanding of the mechanisms underlying US-enhanced hydrogen generation; optimizing operating conditions (e.g., frequency, acoustic power, electrode materials, and solution temperature); and studying hydrogen production from non-aqueous solutions. This review provides a comprehensive framework for future investigation in this evolving field.