INFRARED PHOTOACOUSTIC SPECTROSCOPY OF CATALYTICALLY INTERESTING POWDERS.

This paper describes a photoacoustic cell designed for catalytic studies that can obtain spectra under conditions of up to 400 degree C with gas flow corresponding to a space velocity of 0. 5 s** minus 1. Experiments were performed examining methanol adsorption on silica and Na-Y zeolite. The photoacoustic spectra were able to clearly display the entire spectrum 4000-400 cm** minus **1, so that the C-O stretching band was superimposed on the Si-O bands. Adsorption studies of CO on Pt/Al//2/O//3 and Pt-black showed that photoacoustic spectra may be obtained for supported metal catalysts, but not for massive metal catalysts. Criteria are presented that relate the applicability of PAS to the physical properties of the powdered catalyst.