respectively. Consistent with a photothermal process, for dry gas flow, the three light sources exhibit an Arrhenius-type dependence of the CO2 photo-desorption as a function of applied current (fits not shown here). This shallow Arrhenius dependence looks like a linear trend, which is within the reasonable approximation that the local temperature increases due to light absorption of TiN is proportional to the light power that the sample experiences, thereby releasing CO2. The white light has the shallowest increase of the 3 LEDs, consistent with a small irradiance value (see Fig. ) and discontinuous spectrum in the range of interest, 380 -750 nm. The UV light desorbs the most CO2, closely followed by the red light, consistent with both, the UV and red wavelengths aligning with the absorbance TiN, with the red light being more effective at activating the TiN NPs. In the humid flow, the overall CO2 photo-desorption increases for all three lamps. While the CO2 desorption increases similarly to the dry case for the white light, there is an inflexion point ~400 mA and ~700 mA for the UV and red light, respectively. This behavior could be indicative of a mass-transfer limited regime, due to efficient CO2 desorption being close to the saturation capacity of the PEI system. A competitive mechanism could be a heat transfer limitation of the material system due to illuminating only one contactor half.