Numerical modelling of the adsorption and thermal desorption of NH3 on ZrO2

This paper deals with the interaction of NH3 with ZrO2. The adsorption sites of the ZrO2 surface and the thermal behaviour of the adsorbates formed are examined by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). Kinetic parameters of the adsorption and desorption of NH3 are determined by numerical modelling based on Temperature Programmed Desorption (TPD) studies. Special interest was directed towards TPD spectra, which exhibited an intense peak in the low-temperature range as well as a sample dependent shoulder at higher temperatures corresponding to H3N⋯⋯HO–Zr4+ and H3N⋯⋯Zr4+ surface species, respectively. Kinetic modelling provided activation energies for NH3 desorption between 100 and 105 kJ mol−1 and from 141 to 164 kJ mol−1.