Recently, a team led by Dr. Wang Feng, a researcher at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and Associate Researcher Jia Xiuquan, collaborated with the team of Dr. Richard N. Zare at Stanford University in the field of microdroplet chemistry, achieving new progress. They successfully controlled the activity of hydrogen production through "contact electrification" at the water-oil micro-interface during the aerosolization process. The related findings have been published in the Journal of the American Chemical Society.
The "contact electrification" hydrogen production reaction occurs at the water-oil microdroplet interface. Image courtesy of Dalian Institute of Chemical Physics.
The fragmentation electrification effect is an important charging mechanism. This effect typically occurs in environments such as thunderstorm clouds or waterfalls. When large water droplets or ice crystals break under the influence of airflow or collisions, charge separation occurs. This charge separation is due to the uneven distribution of charges inside the water droplets or ice crystals and the fragmentation process itself. Based on the fragmentation electrification effect of microdroplets and the spontaneous charge transfer characteristics at the water-oil interface, the research team controlled the electron transfer during the atomization fragmentation process to regulate the charge carried by microdroplets per unit mass (gram). Additionally, utilizing characterization techniques such as charge measurement, electron paramagnetic resonance spectroscopy, and gas chromatography, the researchers discovered the process of electron transfer from microdroplets to submicron droplets at the water-oil microdroplet interface. This led to the proposal of a new mechanism for accelerating the hydrogen production reaction in the presence of charge separation-neutralization mechanisms. It was also demonstrated that hydrogen species such as hydrogen radicals generated in the process can undergo in-situ reduction of carbon dioxide. Furthermore, the study found that both charge separation and hydrogen production activity are inhibited when surfactants are added to disrupt the water-oil micro-interface.
Based on these findings, the research team proposed that enhancing the hydrogen production activity of water-oil systems through atomization could facilitate the upgraded utilization of oily wastewater.
Related paper: https://doi.org/10.1021/jacs.4c01455
