Investigating model CeO2 and TiO2 systems by means of Scanning Tunneling Microscopy and Atomic Force Microscopy

Abstract

Atomic scale characterization of materials is important for the fundamental understanding of their properties. Here, model systems of industrially relevant cerium and titanium oxides are characterized with the combination of the Scanning Tunneling Microscopy (STM) and Non Contact Atomic Force Microscopy (NC AFM). Cerium oxide model systems are represented by fully oxidized and partially reduced ultra-thin ceria films supported on copper single crystal. Interaction of the model ceria systems with catalytically important adsorbates (water, methanol) is studied on atomic scale. Titanium oxide model systems are represented by pentacene and C60 molecules adsorbed on the surface of bulk titania in anatase polymorph. Organic layers on titania are studied with intramolecular resolution with the help of the newly developed Double pass scanning mode of NC AFM. The atomic contrast formation mechanisms in STM and NC AFM on ceria and anatase surface are presented. Powered by TCPDF (www.tcpdf.org)

Charakterizace materialu na atomarni urovni je nepostradatelna pro zakladni vyzkum jejich vlastnosti. V teto praci jsou charakterizovany modelove systemy technologicky dulezitych oxidu ceru a titanu kombinaci rastrovaci tunelove mikroskopie (STM) a bezkontaktni mikroskopie atomarnich sil (NC AFM). Modelove systemy oxidu ceru jsou ve forme tenkych vrstev oxidovaneho a redukovaneho oxidu ceru na monokrystalu medi. Je studovana interakce techto modelovych systemu s adsorbaty dulezitymi pro heterogenni katalyzu (voda, metanol) na atomarni urovni. Modelove systemy oxidu titanu jsou ve forme molekul C60 a pentacenu adsorbovanych na povrchu monokrystalu oxidu titanu - anatase. Tyto organicke tenke vrstvy na oxidu titanu jsou studovany s intramolekularnim rozlisenim pomoci nove vyvinute merici metody dvoupruchodoveho rastrovani v NC AFM. Je predstaveno take vysvetleni vzniku atomarniho kontrastu na povrsich oxidu ceru a titanu v STM i NC AFM. Powered by TCPDF (www.tcpdf.org)