Enhanced Hydrogen Production via Photothermal‐Coupled Ultrasound Pyrolysis of Waste Bio‐Oil

Abstract The creation of hydrogen using the lower‐cost feedstock, waste organics (WOs), e. g. kitchen waste bio‐oil, is a win‐win solution, because it can both solve energy problems and reduce environmental pollution. Ultrasound has received considerable interest in organic decomposition; however, the application of ultrasound alone is not a good choice for the hydrogen production from WOs, because of the energy consumption and efficiency. To boost the hydrogen production based on ultrasonic cavitation cracking of bio‐oil, photothermal materials are introduced into the hydrogen production system to form localized hot spots. Materials carbon black (CB), carbon nanotubes (CNT), and silicon dioxide (SiO 2 ) all exhibit significant enhancing effects on the hydrogen production from bio‐oil, and the CB exhibits the most significant strengthening effect among these materials. When the dosage of CB is 5 mg, hydrogen production rate is 180.1 μmol h −1 , representing a notable 1.7‐fold increase compared to the production rate without CB. In the presence of light and ultrasound, the hydrogen production rate can be increased by 66.7‐fold compared to the situation where only light is present without ultrasound.