Morphologies dependence of hydrogen evolution over CeO₂ via ultrasonic triggering

Ultrasonic field can lead to cavitation bubbles explosion, which rises a high-frequency oscillation and generates a high-frequency current in semiconductor nanoparticles in suspension. However, the effect of nanoparticle morphology on ultrasonic-triggered H₂ production is still unclear. To this end, herein, nanorods CeO₂ (nrCeO₂), CeO₂ nanocubes (ncCeO₂), and CeO₂ nanospheres (nsCeO₂) were successfully synthesized. Among them, one-dimensional nrCeO₂ had the most abundant O-vacancies. As revealed by the COMSOL simulation, nanoparticle deformation was easier in nanorods compared with nanocubes and nanospheres, resulting in more efficient charge separation and facilitating H₂ production reaction in nrCeO₂. In detail, within a 5 h’ period, nrCeO₂ presented the highest H₂ production activity of 983.1 μmol g⁻¹ h⁻¹ with the positive charge (q+) trapping agent of CH₃OH, and that of 278.1 μmol g⁻¹ h⁻¹ in pure water. This work presents a new understanding about the relationship between nanoparticle morphology and H₂ production activity, and provides a promising, efficient, and clean H₂ production approach, which can be further extended to multi-field coupling reactor.