Molecular solar–thermal (MOST) systems combine
solar energy
conversion, storage, and release within one single molecule. To release
the energy, different approaches are applicable, e.g., the electrochemical
and the catalytic pathways. While the electrochemical pathway requires
catalytically inert electrode materials, the catalytic pathway requires
active and selective catalysts. In this work, we studied the catalytic
activity and selectivity of graphite(0001), Pt(111), and Au(111) surfaces
for the energy release from the MOST system 3-cyanophenylazothiophene
along with its adsorption properties. In our study, we combine in
situ photochemical IR spectroscopy and density functional theory (DFT).
Graphite(0001) is catalytically inactive, shows the weakest reactant–surface
interaction, and therefore is ideally suitable for electrochemical
triggering. On Pt(111), we observe strong reactant–surface
interactions along with moderate catalytic activity and partial decomposition,
which limit the applicability of this material. On Au(111), we observe
high catalytic activity and high selectivity (>99%). We assign
these
catalytic properties to the moderate reactant surface interaction,
which prevents decomposition but facilitates energy release via a
singlet–triplet mechanism.