Temperature programmed desorption (TPD) is one of the most widely used surface analysis techniques available for materials research science. It has several applications such as knowing the desorption rates and binding energies of chemical compounds and elements, evaluation of active sites on catalyst surfaces and the understanding of the mechanisms of catalytic reactions including adsorption, surface reaction and desorption, analysing material compositions, surface interactions and surface contaminates. Therefore, TPD is increasingly important in many industries including, but not limited to, quality control and industrial research on products such as polymers, pharmaceuticals, clays and minerals, food packaging, and metals and alloys.
When TPD is used with the aim of knowing desorption rates of products that were previously adsorbed on a surface, it consists of heating a cold crystal surface that adsorbed a gas or a mixture of gases at a controlled rate. Then, the adsorbates will react as they are heated and then they will desorb from the surface. The results of applying TPD are the desorption rates of each of the product species that have been desorbed as a function of the temperature of the surface, this is called the TPD spectrum of the product. Also, as the temperature at which each of the surface compounds has been desorbed is known, it is possible to compute the energy that bounded the desorbed compound to the surface, the activation energy.