Chemistry Reference
In-Depth Information
DFT CALCULATIONS FOR
SURFACES OF SOLIDS
4.1
IMPORTANCE OF SURFACES
Surfaces are technologically important in many fields, including catalysis,
interfaces, membranes for gas separations, and semiconductor fabrication.
Understanding the geometry and electronic structure of surfaces is important;
for example, it has been established that there is often a correlation between the
structure of a surface and its catalytic activity. One area of research in catalysis
where DFT has played an important role is the effort to improve the technology
and reduce the cost of the three-way catalysts that reduce CO, NO
x
, and
SO
x
emissions from cars. These catalysts achieve the rather ambitious goal
of oxidizing hydrocarbons and CO while simultaneously reducing NO
x
.
Traditionally, they have incorporated expensive materials such as platinum,
and they have been subject to poisoning under certain conditions. DFT
methods have played an important role in elucidating the mechanisms of
the relevant reactions on catalytic metals, zeolites, and oxides and have
led to improvements in the design of catalytic converters that improve their
efficiency and lower their cost.
Surface science experiments and DFT have often been teammates in very suc-
cessful projects. DFT has been used alongwith ultra-high-vacuum surface science
experiments such as scanning tunneling microscopy (STM), temperature-
programmed desorption, X-ray diffraction, and X-ray photoelectron spectroscopy
