Deposition of two-dimensional (2D) materials onto catalyst
surfaces
is known to alter the adsorption energies of active sites due to the
nanoconfinement effect. Traditionally, these 2D catalyst heterostructures
were prepared by depositing a 2D material onto a pristine metallic
surface. Preparing well-defined 2D monolayers, instead, on metal-oxide
surfaces is challenging, although it is possible via O2 intercalation by oxidizing a metal substrate underneath. Several
studies demonstrate this intercalative behavior of 2D covers, however,
without the preparation of ordered structures, which are imperative
for defining fundamental reaction mechanisms in confined space. We
report the successful preparation and characterization of a well-defined,
ultrathin cuprous oxide-like film grown between h-BN and Cu(111).
The confined surface oxide adopts a “Cu2O-like”
structure resembling the well-studied “44” Cu2O structure, although the oxidation temperature is surprisingly lower
than its uncovered oxide counterpart and the h-BN layer remains intact
following oxidation. Our experimental results, backed by theoretical
simulations, outline the development of a heterostructure with an
h-BN/metal-oxide interface as a model system, utilizing a preparation
method likely transferable to a wide range of 2D/metal heterostructures
and opening the door to new catalyst designs.