FTIR imaging as a high-throughput technique

The first array-based technique was designed specifically to study reactions on solid phase catalysts as IR thermography.9,19 This approach utilizes IR sensitive FPA detectors to measure the temperature of catalysts under reaction conditions. This approach has the advantages of a theoretical high thermal sensitivity, typically several tens of millikelvin, and the ability to study both endothermic and exothermic reactions. The main disadvantage of this approach, however, is the lack of chemical information. It must be assumed that the temperature change is associated entirely with the desired reaction pathway. The presence of unexpected side reactions will not be detected in this approach, as long as they have similar thermal behavior as the reaction under study. 

It is also possible to partially alleviate the problem of chemical insensitivity by incorporating narrow bandpass filters into the optical setup.20 Thus, by choosing an appropriate frequency region, it becomes possible to detect the presence of a particular reactant or product species. While this adds some measure of chemical sensitivity to the thermography approach, it is only capable of monitoring one species at a time. Additionally, the success of this approach relies upon the fact that the spectral bands of the desired species do not overlap with any other species and that unexpected reaction products that have spectral contributions in the region of interest are not present. 

To remove some of the limitations imposed by the approaches mentioned above, Fourier transform infrared (FTIR) imaging has been developed as a high-throughput technique for the study of heterogeneous catalysts.21,22 By combining an array 

An example of a dedicated sampling accessory is the parallel gas phase array (GPA) that was utilized in the gas phase effluent studies mentioned below. For 

---

Figure 6.1 Basic concept of the application of FTIR imaging as a high-throughput technique. Placing multiple samples in the field of view of the imaging spectrometer allows the collection of a single dataset that contains information from all samples. Reprinted with permission from ACS.

---