 Operando spectroscopy is a class of methodology, rather than a specific spectroscopic technique such as FTIR or NMR.Operando spectroscopy is a logical technological progression in in situ studies.Catalyst scientists would ideally like to have a "motion picture" of each catalytic cycle, whereby the precise bond-making or bond-breaking events taking place at the active site are known; this would allow a visual model of the mechanism to be constructed.