A surface-promoted redox reaction occurs spontaneously on solvating inorganic aerosol surfaces

Spontaneous chemistry on aerosol surface Interfacial redox chemistry plays an important role in the formation of gas molecules and aerosol particles. However, the characterization of such heterogeneous processes is challenging, and they are often omitted in chemical kinetics models. Using ambient-pressure x-ray photoelectron spectroscopy combined with molecular dynamics simulations, Kong et al . discovered spontaneous redox chemistry promoted by the surface at the first stages of the solvation process on a typical inorganic aerosol surface of ammonium sulfate (see the Perspective by Ruiz-Lopez). Several unexpected species have been identified as being possible products of a sulfate-reducing ammonium oxidation reaction, and this may help to resolve some of the enduring conundrums of atmospheric chemistry. The present results could also be useful for the development of wastewater treatments and other industrial technologies. —YS