SEMINARS OF DEPARTMENT OF CHEMISTRY – UNIVERSITY OF CRETE
We invite you to attend the event
“Chemistry beyond the bulk: Reactivity at air-water interfaces”
Dr. Maria Angelaki
Aarhus University, Denmark
TUESDAY / JUNE 23, 2026 / 12:00
The lecture will be hosted on the Seminar room (Department of Chemistry)
Abstract
Water covers about 71% of the Earth’s surface (e.g., oceans and glaciers) and is essential for all biological systems. Although bulk water is inert, water droplets provide a favourable environment for chemical processes. The unique properties of the air–water interface can accelerate chemical reactions and initiate the spontaneous reduction of organic compounds. In our group, we found that OH radicals can form spontaneously near the air-water interface of aqueous aerosols in the absence of any precursor, catalyst, or light. OH⁻ ions may partially exist, to a small extent, as an ion-radical pair (OH···e⁻), which can undergo charge separation in the presence of strong interfacial electric fields, producing OH radicals. Hydrogen peroxide (H2O2), an important atmospheric oxidant, is subsequently formed through a complex reaction mechanism. The extent of oxidant formation at the air–water interface was also found to depend on the ionic composition of the droplets and particle acidity. We further showed that this chemistry is also important in organic particles. Solid organic particles undergo OH-driven oxidation under typical tropospheric relative humidity conditions, and this oxidation depends on particle size, confirming a surface-driven process. The production of OH radicals at the air–water interface of organic particles therefore represents a previously unrecognized but important pathway for aerosol oxidation, particularly under nighttime conditions when photochemical oxidant sources are limited. Overall, our work highlights the air–water interface as a uniquely reactive environment capable of driving unexpected oxidative chemistry in atmospheric aerosols, revealing overlooked pathways that may influence aerosol aging, atmospheric oxidation capacity, air quality, and climate processes.
Short CV
Maria obtained her bachelor’s degree in chemistry from the Department of Chemistry at the University of Crete in 2015. In 2017, she completed her Master thesis in Physical Chemistry at the same department, working in the laboratory of photochemistry and kinetics (LAPKIN) under the supervision of Dr. Vassileios Papadimitriou. In 2021, she obtained her PhD in Physical and Analytical Chemistry from the same laboratory, under supervision of Dr. Vassileios Papadimitriou and the co-supervision of Prof. Maria Kanakidou. During her PhD, she studied the gas-phase tropospheric degradation of furans, important biomass-burning products, by several tropospheric oxidants, and evaluated their fate and impact on climate and air quality. After a short postdoctoral position at the environmental chemical processes laboratory (ECPL, group of Prof. Kanakidou), she joined the group of Dr. Christian George at the CNRS in Lyon, France, in 2022. Her research focused on processes that occur at the air-water interface of aqueous droplets that lead to the spontaneous formation of tropospheric oxidants. Her studies revealed critical information about the oxidation capacity of the troposphere and gave new insights about the oxidation processes of organic aerosols during nighttime. Since 2025, she is a postdoctoral researcher at Aarhus University, in the group of Prof. Fabian Mahrt. Her research is now focusing on the cloud-forming ability of secondary organic aerosols produced from reactions between organic compounds and tropospheric oxidants, as well as on their phase state and other physicochemical processes.
