Water adsorption beyond monolayer coverage on ZnO surfaces and nanoclusters
2008 (English)In: SOLAR HYDROGEN AND NANOTECHNOLOGY III / [ed] Westin, G, 2008, Vol. 7044, E440-E440 p.Conference paper (Refereed)
The surface structures of ZnO surfaces and ZnO nanoparticles, with and without water, were studied with a ReaxFF reactive force field (FF) and molecular dynamics (MD) simulations. The force field parameters were fitted to a training set of data points (energies, geometries, charges) derived from quantum-mechanical DFT/B3LYP calculations. The ReaxFF model predicts structures and reactions paths at a fraction of the computational cost of the quantum-mechanical calculations and as such allows dynamical simulations of reactive process for large (>>1000 atoms) and long (> 100 ps) timescales. Our simulations give the following results for the (10 (1) over bar0) surface. (i) The alternating H-bond pattern of Meyer et al. for a single monolayer coverage is reproduced by our simulations. This pattern is maintained at elevated temperatures (COOK). (ii) At coverages beyond one water monolayer we observe enhanced ZnO hydroxylation at the expense of ZnO hydration. (iii) This is achieved through an entirely new H-bond pattern mediated via the water molecules in the second layer above the ZnO surface. (iv) During a water desorption simulation at T=300K we observe that the desorption rate slows significantly when two monolayers remain. (v) Simulations of nanoparticles in the presence and absence of water suggest that water plays a key role in the determination of nanoparticle shape by catalyzing surface reconstruction reactions and stabilizing specific surface structures.
Place, publisher, year, edition, pages
2008. Vol. 7044, E440-E440 p.
, PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE), ISSN 0277-786X ; 7044
Water adsorption, zinc oxide, hydroxylation, hydrogen bonding, molecular dynamics simulation
Research subject Inorganic Chemistry
IdentifiersURN: urn:nbn:se:uu:diva-108387DOI: 10.1117/12.795337ISI: 000260995300007ISBN: 978-0-8194-7264-9OAI: oai:DiVA.org:uu-108387DiVA: diva2:235686
Conference on Solar Hydrogen and Nanotechnology III San Diego, CA, AUG 13-14, 2008
Dep. of Materials Chemistry, The Ångström Laboratory, Uppsala University, Box 538, S-75121 Uppsala, Sweden2009-09-172009-09-172015-02-13