1 research outputs found
Catalyzed SnO<sub>2</sub> Thin Films: Theoretical and Experimental Insights into Fabrication and Electrocatalytic Properties
SnO<sub>2</sub> thin films are studied experimentally and from
first-principles as model supports for Pt nanoparticle catalysts in
an acidic environment. SnO<sub>2</sub> thin film supports are attractive
model systems because composition, microstructure, and surface termination
can be tailored by varying the deposition parameters. SnO<sub>2</sub> films are synthesized by reactive dc magnetron sputtering, and the
effects of the deposition conditions on the physicochemical and electrochemical
properties are investigated experimentally and theoretically. Variation
of the deposition conditions results in limited long-range order SnO
or SnO<sub>2</sub> films. Annealing in either case leads to well-crystallized
SnO<sub>2</sub> films, but with different growth directions. Films
deposited as SnO<sub>2</sub> show only growth along the [110] direction,
while SnO<sub>2</sub> films formed from deposited SnO show no preferred
orientations. Hybrid density functional theory (DFT) suggests that
growth along the [110] direction is driven by (110) being the lowest
energy surface, while the loss of orientation in the SnO derived films
originates from an almost degenerate set of surface energies at the
SnO|SnO<sub>2</sub> equilibrium. The oxygen reduction reaction activity
of Pt nanoparticles depends on the SnO<sub>2</sub> film orientation.
A 2-fold higher catalytic activity is observed for Pt nanoparticles
on the SnO<sub>2</sub> film without preferential orientation compared
to Pt on SnO<sub>2</sub> grown along the [110] direction, pointing
to the presence of strong surface-dependent metalāsupport interaction