In the flow reactor system, ATR-FTIR spectrophotometry is coupled with atmospheric pressure quadrupole residual gas analyzer (RGA) for multi-analysis of chemical and photochemical reactions on metal oxide particles under simulated environmental conditions (i.e. relative humidity, temperature, solar flux). During the experiment, a thin layer of metal oxide particles deposited on the ATR crystal, placed in the internal compartment of the FTIR spectrometer (Thermo Nicolet is50), is exposed to a steady stream of traces gases. The reactive  gases are mixed well prior to introduction to the reaction chamber. Kinetics and speciation of new surface product formation (monodentate, bidentate and bridged) are analyzed by collecting surface IR spectra as a function of time. Primary gases and secondary gas products are quantified using mass spectrometry.

 

Here, temperature is controlled by using a flow through jacketed ART crystal (PIKE Technologies) and a refrigerated/heated circulator (Julabo). Relative humidity is introduced by passing a controlled dry air flow through water bubbler and continually monitored via RH sensor attached to the reaction chamber. Simulated sun light (~ 1 sun)  is provided using a 150 W xenon solar simulator (Newport).