Application of a Temperature-Programmed Desorption Technique to Catalyst Studies

Publisher Summary This chapter focuses on the application of a temperature-programmed desorption method to obtain information on the active centers of catalysts. In principle, this method is similar to the flash-filament desorption method. However, modifications have been made to make the construction and operation of the apparatus easier and to adapt it to studies of materials other than metals—oxide catalysts. An additional important feature of the modified technique is that it permits simultaneous study of a chemisorption process and the surface reaction that accompanies it. The temperature-programmed desorption technique consists of the several steps: (1) catalyst pretreatment, (2) preadsorption of the adsorbate, (3) evacuation after preadsorption to remove the physically adsorbed gas, (4) programmed desorption of the residual chemisorbed gas into the stream of a carrier gas, (5) detection of the desorbed gas in the carrier, and (6) trapping and analysis of the desorbed gas to establish its identity.