text: Operando spectroscopy has become a vital tool for surface chemistry. Nanotechnology, used in materials science, involves active catalytic sites on a reagent surface with at least one dimension in the nano-scale of approximately 1–100 nm. As particle size decreases, surface area increases. This results in a more reactive catalytic surface. The reduced scale of these reactions affords several opportunities while presenting unique challenges; for example, due to the very small size of the crystals (sometimes <5 nm), any X-ray crystallography diffraction signal may be very weak.
  As catalysis is a surface process, one particular challenge in catalytic studies is resolving the typically weak spectroscopic signal of the catalytically active surface against that of the inactive bulk structure. Moving from the micro to the nano scale increases the surface to volume ratio of the particles, maximizing the signal of the surface relative to that of the bulk.
  Furthermore, as the scale of the reaction decreases towards nano scale, individual processes can be discerned that would otherwise be lost in the average signal of a bulk reaction composed of multiple coincident steps and species such as spectators, intermediates, and reactive sites.