Prof. Hoffmann's research current interests and support cover number of different areas of environmental chemistry and applied physical chemistry. Part of his research group is focused on atmospheric photochemistry related to the production of secondary organic aerosol, the photochemistry of marine aerosols generated via wave breaking, and on the photochemistry of inorganic and organic molecules of interest in ice-dominated environments. In addition, his research group has been examining the detailed nature of the air-water interface and the change in chemical reaction mechanisms at the interface compared to the bulk phase of liquid water droplets and haze aerosol. In particular, the Hoffmann group has been examining the preferential accumulation of anions as a function of ionic radii, polarizability, and hydration energies at water-droplet-air interfaces using electrospray mass spectrometry. In a related study, students and post-doctoral scholars are exploring the photochemical and interfacial chemistry of isoprene and other terpenoids in haze aerosol. From the fundamental physical chemistry perspective, the group is also exploring the natural of acidity and basicity at the air-water interface and its role in catalyzing the uptake of gas phase molecules.
In the area of water treatment technology, the Hoffmann group is continuing to explore the use of ultrasonic irradiation, semiconductor phototcatalysis, semiconductor electrochemistry, and combinations of approaches utilizing ozone as a supplemental oxidant in order to eliminate chemical contaminants from water.
In recent years, there is a renewed focused on solar fuels production via photocatalytic water splitting to produce molecular hydrogen and via the photocatalytic reduction of CO2 in to useful products such as syngas, methane, and higher order hydrocarbons. The Hoffmann group is actively involved in issues related to solar fuels production from the synthesis of new hybrid semiconductor materials that are efficient water.