H2O and H2 interaction with ZnO surfaces: A MNDO, AM1, and PM3 theoretical study with large cluster models

✍ Scribed by João B. L. Martins; Juan Andrés; Elson Longo; C. A. Taft

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 686 KB
• Volume: 57
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1996)57:5<861::aid-qua5>3.0.co;2-w

✦ Synopsis

We investigated the adsorption and heterolytic dissociation of H 2 0 and H2 molecules on a (ZnO)*? cluster corresponding to ZnO (OOOl), (OOOl), and (lOi0) surfaces using MNDO, AM^, and PM3 semiempirical procedures. The geometry of the adsorbed molecule has been optimized in order to analyze binding energies, charge transfer, and preferential sites of interaction. The adsorbed species interact most strongly when it is bonded to the twofold coordinated zinc atom of the cluster surface. The interaction of the H 2 0 molecule with the surface of ZnO has a charge transfer from H 2 0 to the surface ranging between 0.17 and 0.27 au. The neighboring atoms of the surface are the main receptors during the process of charge transfer. Our results indicate that there is a weak bonding of the hydrogen atom from OH with the oxygen surface atom that could produce the O--H....O band. The interaction of the H2 molecule with the surface is generally weak and only the PM3 method yields a strong binding energy for this interaction. There is a charge transfer from the H2 molecule to the surface. The chemisorption of H on oxygen atom of the surface transfer charge from the surface to the H. We also calculated the vibrational analyses for these interactions on ZnO surface and compared our results with available experimental data.