Determining the Reaction Mechanisms of Photo-Thermo Synergetic Processes by Kinetic Investigations

Photo-thermo catalysis utilizing light has been a promising strategy to improve the conventional thermal catalytic activity and attracts great attention nowadays. However, how heat works in synergy with light radiation is still unclear. This Concept article is trying to clarify the specific contents via summarizing the kinetic studies including 1) proposing elementary steps through pressure dependence studies, 2) estimating reaction barriers through measuring the apparent activation energies and 3) assigning the kinetically relevant step(s) with kinetic isotope effects (KIE) as well as 4) exploring the relationship of the reaction rate with the light excitation wavelength and light intensity. The challenges in kinetic studies such as describing the light-induced carrier transfer process, the surface temperature under light illumination as well as reaction intermediates were discussed at the same time. Finally, an outlook about kinetic studies in clarifying the photo-thermo catalysis reaction mechanism was proposed.