Photothermal catalysis combines light and heat, and the combination is easy to claim but hard to prove. The central experimental question: does illumination do anything beyond heating the catalyst? A well-designed fixed-bed campaign answers it with controls, not adjectives.
Run the same catalyst in four conditions: dark at reaction temperature (pure thermal), illuminated at the same surface temperature with thermal compensation (photo contribution at matched heat), illuminated with free heating (combined), and dark at the temperature light alone produces (light-as-heat check). The comparison between these four traces is the entire argument.
Surface temperature under illumination is not the oven temperature. Use an IR camera or a contact probe to record the catalyst surface itself, otherwise "thermal compensation" compensates the wrong number and the whole matrix collapses.
If illuminated-at-matched-temperature exceeds dark-at-matched-temperature, light contributes non-thermally, that is photothermal synergy in the strict sense. If combined performance merely tracks the hotter surface temperature, light is acting as a heater, a useful but different phenomenon that should be reported as such.
State light intensity and spectrum at the bed, surface temperature in every condition, and the compensation method. Photothermal papers are judged on these details, because the field has learned to distrust synergy claims without them.
Perfectlight's photothermal fixed-bed systems are built for exactly these four-condition campaigns; see solutions.
