Surface chemistry at the liquid/solid interface

In this Prospective, a critical overview is provided on the status and future of the analytical techniques available for the study of chemistry at liquid/solid interfaces. A number of spectroscopies already available are identified, including infrared absorption, surface-enhanced Raman (SERS) and sum frequency generation (SFG) to obtain vibrational information, and second harmonic generation (SHG) and X-ray absorption (XAS) to provide electronic details of surfaces and adsorbates. X-ray scattering and X-ray diffraction techniques are also used for structural characterization, and surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) to follow adsorption uptakes and kinetics. Finally, optical and scanning microscopies add a spatial dimension to these studies. Overall, a number of surface-sensitive techniques do already exist to address chemical issues at liquid/solid interfaces, but those are still limited, and have perhaps not been exploited to their fullest yet. There is also a need for more cross collaboration among different research communities, and for new and clever developments to augment the toolbox of liquid/solid interface characterization.

Research highlights► Liquid/solid interfaces are ubiquitous in nature, and require renewed effort from the surface science community. ► Molecular vibrational information at liquid/solid interfaces can be obtained by using IR, Raman, and SFG spectroscopies. ► Electronic information can be extracted by optical and X-ray absorption spectroscopies. ► X-ray scattering and diffraction techniques are well suited to provide structural information. ► Quantitative adsorption isotherms and kinetics can be obtained with SPR and QCM, and spatial information recorded using optical and scanning probe microscopies.