h-BN/Metal-Oxide Interface Grown by Intercalation: A Model System for Nano-Confined Catalysis

Abstract

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 O 2 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 "Cu 2 O-like" structure resembling the well-studied "44" Cu 2 O 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.

Operando XPS for Plasma Process Monitoring: A Case Study on the Hydrogenation of Copper Oxide Confined under h-BN

“…Instead, the shift presumably is an electronic effect as the removal of oxygen at the h-BN/Cu interface changes the band offset and thus lowers the referenced Fermi level. A related reverse effect was seen during oxidation of pristine h-BN/Cu(111) where a peak shift to lower BE is seen upon oxidation . This same behavior has also been seen for the Co/h-BN interface exhibiting p-type band bending .…”

“…This intercalative oxidation can occur thermodynamically, even at room temperature (RT), if the partial pressure of oxidizing species is high enough. This can limit the lifetime of pristine unoxidized h-BN/Cu heterostructures to a few weeks in an ambient environment. − In addition to intercalative oxidation, deintercalation has also been demonstrated, although the ability to subsequently intercalate a reducing molecule and recover the initial interface without completely destroying the h-BN layer has been more challenging to achieve.…”