Literature review on developments in in-situ/operando techniques for studying reaction kinetics, changes in oxidation state and phase composition especially during redox reactions including the state of the art and new characterization techniques. Techniques to characterise catalyst surface phase transitions in redox reactions are SXRD (surface x-ray diffr.), XAS (x-ray abs. spectr.), infrared techniques including FTIR and DRIFTS, UV-Vis, STM, and DP-ETEM (differentially pumped-environmental TEM). These techniques are normally coupled with analytical devices such as GC and/or MS to obtain kinetic information.