Temperature programmed techniques in catalysis: Study of fuel cell anodes

Temperature programmed (TP) experiments involve using small amounts of powdered catalyst (∼50–300 mg) in a microreactor. In the case of TP desorption (TPD), the catalyst is pretreated to obtain a particular state and then exposed to reactants. The reactor is then flushed with inert gas as the reactor temperature is linearly increased with time. Any species adsorbed on the catalyst surface are desorbed, at temperatures indicative of their strength of adsorption, and detected with a mass spectrometer. The theory and experimental procedure behind general TP techniquesare presented. The use of specific TP techniques, such as TPD, TPR (reduction), TPO (oxidation), and TP Rx (reaction), for the study of electrocatalysts for fuel cell applications are discussed and results presented.