(704f) Quantum Confined 2D Metals: A Novel Platform for Heterogeneous Catalysis

The creation of a green economy demands fresh approaches in energy-related technologies. 2D materials have been touted as a compelling platform in several key green energy related areas; however, a lack of scalable synthesis methods for producing high-quality 2D materials has limited interest from the catalysis community. Confinement heteroepitaxy (CHet) is a recently developed breakthrough technique for synthesizing large-area, air- stable 2D metals, which could unlock 2D materials in catalysis. CHet produces 2D metals with a protective capping layer of graphene so it can be deployed with elements across the periodic table including transition metals. Quantum confinement, strain from forced lattice matching with the silicon carbide (SiC) substrate, and non-centro symmetric bonding (i.e., covalent to metallic to van der Waals) creates not just atomically thin metals, but entirely novel forms of metals.

This work aims to develop 2D metals for heterogeneous catalysis. Because the original intention for CHet was toward electronic applications, it was developed for growth on wafers; thus, suffering from a low surface to volume ratio and form factor that differs fundamentally from industrial catalysts. Here, CHet is extended from wafers to microparticles to better match industrial requirements, and early evidence such as the presence of ultra-low frequency (sub 100 cm^-1) Raman peaks, which are the signature of 2D metals grown on SiC, shows the successful intercalation of 2D Ga on graphene-covered SiC microparticles. The catalytic activity of 2D metals is screened by measuring the binding strength of various gases using temperature programmed desorption (TPD). In addition to extending CHet to microparticles, a ceramic, 3D-printed microreactor for testing the catalytic activity of 2D metals on wafers is developed to serve as a model system to study the fundamentals of 2D metal catalysis. This work was supported by NSF DMR-2011839 through Penn State MRSEC - Center for Nanoscale Science.