Danish scientists at the University of Aarhus have demonstrated a technique, that utilizes a scanning tunneling microscope (STM) and something called density functional theory calculations (DFT), to make movies of chemical reactions.
Wendt, a post-doc at the Interdisciplinary Nanoscience Center (iNANO) at the University of Aarhus in Denmark, stresses that it is not easy to get such high-resolved STM movies but that there is a great potential to unravel how a surface catalyzed reaction occurs on an oxide surface.
“Using averaging techniques such as vibration spectroscopy, which can be applied for the study of powder samples, it is often impossible to identify intermediate species on well-characterized single crystal surfaces,” says Wendt. “In our paper (Observation of All the Intermediate Steps of a Chemical Reaction on an Oxide Surface by Scanning Tunneling Microscopy), we demonstrate, for the first, time how time-lapsed STM imaging can successfully reveal unprecedented details about the intermediate steps for a surface catalyzed reaction.”
The paper was first-authored by Jesper Matthiesen who is now at Pacific Northwest National Laboratory. The team, which included members of iNANO’s Scanning Probe Microscopy Group, led by Flemming Besenbacher, and Theoretical Surface Science Group, led by BjÃ¸rk Hammer, specifically studied the oxidation of hydrogen adatoms by oxygen molecules on rutile titanium dioxide (110) by high-resolution STM.
Read on at Nanowerk…
Image: STM images of the h-TiO2(110) surface before (left) and after 4 L oxygen exposure at ∼165 K (right). Symbols in image on the left indicate single H adatoms (hexagon) and next-nearest H adatoms (rectangle, full line). The circles in he image on the right indicate the newly formed species in the titanium troughs. (Image: Stefan Wendt, iNANO)