Measuring acidity in zeolites using temperature programmed desorption

Temperature-programmed desorption (TPD) of basic molecules from the surface of zeolites has been extensively used to measure their acidic properties. The TPD experiment consists of adsorbing a base molecule on the material of interest and, while flushing the surface with an inert gas, linearly ramping the temperature and measuring desorption of the base. By quantitatively measuring the amount of base desorbed and noting the temperature(s) of desorption, information can be obtained on both the intrinsic and extrinsic acid properties in a single experiment.