The Area under Desorption Curve, or TPD, is a measure of the total number of particles that are desorbed from a surface during a thermal desorption process. This value is important because it provides information about the surface coverage and adsorption strength of the particles on the surface.
The Area under Desorption Curve is calculated by integrating the desorption curve, which plots the amount of desorbed particles as a function of temperature. This integration gives the total area under the curve, which represents the total number of particles desorbed.
The Area under Desorption Curve takes into account the entire desorption process, including both low and high temperature desorption. Peak height, on the other hand, only reflects the maximum amount of particles desorbed at a specific temperature. The TPD value is therefore considered a more accurate measure of the total number of desorbed particles.
Yes, the TPD value can be used to calculate the desorption energy of particles on a surface. This can be done by fitting the TPD data to a desorption model and using the integrated area to determine the desorption enthalpy.
One limitation of using the TPD value is that it assumes all particles are completely desorbed from the surface. In some cases, a small fraction of particles may remain adsorbed even after the desorption process is complete. Additionally, the TPD value is affected by the heating rate and may not accurately reflect the true desorption behavior of the particles.