Coupling Diffuse Reflectance Fourier Transform Infrared Spectrometry With Gas Chromatography (DRIFT–GC): a High-performance Coupled Technique for Catalyst Characterization

Abstract

The combination of diffuse reflectance Fourier transform infrared spectrometry and gas chromatography (DRIFT–GC) was applied to the thermal characterization of solid materials. In the instrumental design, particular attention was devoted to minimizing the time delays between the responses of the DRIFT and the GC detectors. It was thus possible to correlate the changes in the IR spectrum with the composition of the gas phase as a function of the linearly increasing temperature. Manganese carbonyl [Mn ₂ (CO) ₁₀ ] dispersed on a porous zeolitic matrix was chosen as reference material to test and validate the analytical methodology, since it combines a simple and predictable decomposition chemistry with a well defined infrared spectrum. Improved insights into the thermal characterization of solid materials and catalysts were achieved with this coupled technique. All gas-phase processes, which are generally hidden to IR investigations, can be revealed and studied. Moreover, the ‘fingerprinting’ capabilities of IR spectrometry allow the deconvolution of the elementary processes of gas evolution, greatly improving the resolution of temperature programmed techniques.