Theoretical analysis of Polyethylene terephthalate (PET) adsorption on Co and Mn-doped ZnO (000-1)

Abstract

We have studied, using DFT calculations, the adsorption of Polyethylene Terephthalate (PET) on the pristine and doped polar ZnO (000-1)-O surfaces. The considered dopants are Cobalt and Manganese. The obtained results, before PET adsorption, show that the incorporation of Co and Mn in the ZnO surface produces oxygen passivation, a blueshift, and an important increase of magnetic moment. These facts are important to the control and development of devices in several areas such as catalysis and spintronic. For PET adsorption on pristine ZnO (000-1)-O surface is observed the formation of two hydroxyl and a carbonyl groups. Moreover, the magnetic moment of the pristine ZnO surface is zero after PET adsorption. This behavior is attributed to the reconstruction and passivation due to H atoms adsorbed on the surface. The PET adsorption produces a blueshift when it is adsorbed on pristine and doped ZnO (000-1)-O. This adsorption produces a decrease (increase) of the magnetic moment value for Co (Mn) doped surface, from 16.8 µB to 15.6 µB (6.2 µB to 16.6µB). Finally, the computed adsorption energy for both doped surfaces shows that the adsorption is energetically favorable and the process is exothermic. These values are -4.8 eV and -9.8 eV for Co and Mn-doped surfaces, respectively. Then we can conclude that PET adsorption is better in Mn-doped than Co-doped ZnO (000-1)-O.