Water at Metal Oxide Interfaces: To Dissociate or Not to Dissociate?

Metal oxides are a major component of suspended aerosol particulate matter. The molecular level understanding of metal oxide surfaces has important implications in trace gas adsorption and/or chemical processing in atmospheric aerosol chemistry. The extent to which water molecularly adsorbs and/or dissociates at metal oxide interfaces under ambient conditions is becoming increasingly recognized through fundamental studies via spectroscopy and microscopy tools. We will be presenting recent efforts to understand the interfacial chemistry of metal oxide single crystal and thin film surfaces exposed to ambient water vapor conditions using in-vacuo X-ray Photoelectron Spectroscopy (XPS), ambient pressure XPS, scanning tunneling microscopy (STM), and computer simulations. Results highlight the importance of surface chemistry, metal oxide crystal termination, and external humidity conditions on the interfacial dynamics and chemistry of water at metal oxide interfaces.