A ZnO-based Catalytic System for the Synthesis of Hydrogen Peroxide from Air

Hydrogen peroxide (H₂O₂) has a wide range of applications as an eco-friendly and sustainable oxidant. However, the clean, efficient and convenient synthesis of this compound remains challenging. This work demonstrates a rationally designed electron-self-supplied catalytic system capable of generating H₂O₂ from water and atmospheric oxygen without extra energy input. This catalytic system is made of a ZnO coating containing oxygen vacancies and a Zn substrate. The ZnO catalyst layer obtains electrons from the Zn substrate to synthesize H₂O₂. The H₂O₂ concentration produced by this catalytic system is up to 17.9 mM without any secondary processing. This remarkably high concentration is attributed to the formation of a liquid film on the hydrophilic ZnO surface that promotes the oxygen reduction reaction by accelerating the transfer of oxygen from the ambient air to the catalyst surface. By integrating with atmospheric fog collection, this system can continuously collect H₂O₂ directly from the air.