Dilute streams of CO2 were obtained as cylinders of pre-mixed 400 ppm CO2 in N2 from Matheson and humidified by diverting the gas flow through a deionized water bubbler. A flow of 100 sccm was chosen and regulated through a mass flow controller, as illustrated in Figure and photographed in Figure . A flow of 100 sccm of 400 ppm CO2 in N2 is introduced in a quartz cuvette hosting a flat piece of the PEIloaded contactor "coated" with TiN powder. The CO2 stream can also be diverted to a water bubbler to simulate 100% relative humidity. The gas flow exiting the septum-capped cuvette passes through an infrared detector calibrated for CO2 and H2O signals, the LI-COR Ò -850 detector. In this study, two methods of amine-regeneration were used: thermal regeneration, where the cuvette is immersed into an oil bath at T~110 °C, or photo-driven regeneration. The main body of research was conducted using LEDs (300-400 mW/cm 2 ) centered at ~625 nm, ~385 nm, or a broad-spectrum white LED. The focus length from the LED to the sample is 20 cm.