2D confined metals (2D-M) under heteroepitaxial relations with graphene (Gr) allow for the potential control of chemical properties of the 2D-M by an external electric field. If this external electric field is supplied by an insulating substrate (such as a dielectric or a ferroelectric), then it can enable a non-Faradaic manipulation of electrocatalytic reactions via the M-Gr electrocatalyst system. In this work, we will explore the architecture of a 2D metal-graphene (2D M-Gr), where the substrate is supplying an electric field as well as fulfilling the role of the insulating substrate (dielectric) in the system. The insulating substrate will carry an embedded electron charge at the interface between two dielectric (DE) layers, close to the surface of the metal, allowing for electronic influence on the metal. In this system, graphene acts as an imperfect screener of electric fields allowing the dielectric/ferroelectric-generated field to influence the metal. We find that providing an approximate potential of 0.1 V yields a significant increase in the hydrogen evolution current within a 2D platinum/graphene (2D Pt/Gr) system. Extended X-ray absorption fine structure (EXAFS) studies are used to examine 2D M-Gr epitaxy. EXAFS results indicate a strain condition imposed by Gr on the metal grown, where Gr is constraining nearest-neighbor distances through epitaxial directions. Experimental research on the strain induced in graphene-templated Pt monolayers by Alamgir et al. found that a single graphene layer induces a 3.5% compressive strain on the Pt adlayer deposited onto it, increasing the catalytic activity of the system In the 2D M-Gr system, our strained, epitaxially grown metal on Gr will be demonstrated on an Au/Gr/DE and Pd/Gr/DE system.

References:

1. Abdelhafiz, Ali, et al. “Layer-by-Layer Evolution of Structure, Strain, and Activity for the Oxygen Evolution Reaction in Graphene-Templated PT Monolayers.” ACS Applied Materials & Interfaces, vol. 7, no. 11, 2015, pp. 6180–6188., https://doi.org/10.1021/acsami.5b00182.