Wed. joint seminar

[Cond.Matt. & Stat.Mech.Section]

JOINT ICTP/SISSA CONDENSED MATTER SEMINAR





Luigi Stasi Seminar Room -   ICTP Leonardo Building   (first floor)





Wednesday, 24 March -     4:00 p.m.





Michiel SPRIK  ( University of Cambridge )



"Aligning energy levels at the  TiO2 -water interface



Abstract





When solids come in contact with water the band states in the solid  
shift energy position.  For metal oxides this shift is moreover pH  
dependent as a result of protonation or deprotonation of hydroxyl and  
water molecules adsorbed on the surface.  These surface potentials  
determine the relative position of the electronic states of the solid  
with respect to states of molecules or ions in solution.  This so- 
called band alignment problem is therefore crucial for the  
understanding of the redox properties of the interface.  In this talk  
we discuss our density functional theory based molecular dynamics  
approach to this problem using the application to the rutile TiO2  
(110) water interface and the aqueous hydroxide anion as example. The  
idea is to refer ionization potentials and electron affinities to the  
solvation free energy of the proton in the same supercell establishing  
an effective computational normal hydrogen electrode.  The solvation  
free energy of the proton is computed using a recently developed  
method for reversible proton insertion.