Catalyst–support
interactions are known to be of great importance
for the performance of supported oxide catalysts such as supported
vanadia. With the aim of enhancing the oxide–support interactions,
we propose a strategy for the controlled synthesis of embedded oxide
catalysts using atomic layer deposition (ALD). As demonstrated for
vanadia (VO
x
), the synthesis is based
on the sequential deposition of VO
x
and
the “support” material (Al2O3,
SiO2, TiO2) onto graphene oxide, which serves
as a sacrificial carrier matrix facilitating the embedding of VO
x
, followed by template removal by calcination
or ozone treatment. Detailed characterization of the synthesis process
and the final catalysts is carried out using multiple spectroscopic
(Raman, UV–vis, XPS), thermogravimetric, and electron-microscopic
(TEM, EELS) analyses. The successful formation of a VO
x
–support interphase is confirmed by UV Raman
spectroscopy. Despite the high loadings (L
V > monolayer coverage) of accessible sites, the embedded VO
x
is present in a dispersed state in the case
of the
ozonolyzed samples. Structural models are proposed to account for
the observed behavior. The activity of the embedded VO
x
catalysts is verified in the oxidative dehydrogenation
(ODH) of ethanol and compares favorably with reported data on conventional
supported catalysts. Compared to the literature, the ozonolyzed VO
x
/Al2O3 catalysts show
a significantly improved performance, whereas the VO
x
/SiO2 catalysts define a benchmark. Our results
demonstrate the feasibility of rational catalyst engineering of supported
oxide catalysts.