Diffuse Reflection Infrared Spectroscopy (Drifts): Application to the in Situ Analysis of Catalysts

Institut français du pétroleThe diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) technique, less practiced than the transmission mode because of its limitations, is extremely useful, indeed indispensable, for non-transparent materials and/or for in situ measurements at elevated temperature. The authors describe the principles of this technique and its advantages over transmission infrared spectroscopy. The application of DRIFTS to the characterization of catalysts is illustrated by two studies conducted on the interaction of molybdenum with the precursor of fuel desulphurization catalysts, and on the in situ modifications under reactive gases of catalysts for reducing nitrogen compounds in exhaust gases.