Improving hydrogen generation from biomass and solid waste by combining sonophotocatalysis through carbon-based materials: Challenges and future perspectives

Environmental pollution is becoming one of the main issues facing human civilisation as a result of the world's growing industrialisation. Using limitless solar energy, photocatalysis may be used to address environmental issues. Whilst, the incorporation of ultrasonic cavitation in various processes such as the Fenton-like process, electrochemical process, and especially sono-photocatalysis offer ideal conditions for increasing biomass fragmentation and conversion into target products and green hydrogen within a lesser reaction time. The scientific community and industry have taken a serious interest in the intensification of ultrasonic processes for a variety of applications, as well as the resulting synergistic effects based on conventional comparisons in literature. In light of this, the purpose of this review is to summarize the current research in the field, provide an overview of the recent studies on ultrasound-assisted different catalytic processes for hydrogen production and discuss their limits and validity, comparing them to conventional techniques. Finally, a few future perspectives in the form of suggestions on ultrasound-assisted photocatalysis for hydrogen production from various biomass models and different wastes, and highlighting the role and recent evolution of carbon-based materials in this field, are presented together with current issues and challenges to clarify future attitudes in the hopes of exploring this ideal combination for large-scale H2 production.