(532dp) Programmable Catalysts: Metal/Oxide-Graphene Catalytic Condensers

Precise control of electron density at catalytically active sites enables tunable surface chemistry and enhancement of chemical reaction rates. Combining concepts from metal-oxide-semiconductor field-effect transistors (MOSFETs) and heterogeneous catalysts, we successfully fabricated a catalytically active high-k layered device that allows for charge modulation to affect activity. This concept device, i.e. a catalytic condenser, has the following structure: a catalytic layer/graphene/HfO₂(70 nm)/p-type Si, and it relies on both the high-k insulator or dielectric layer and 2D monolayer graphene to accumulate or deplete electrons from the catalytic sites. The graphene-dielectric platform also enables the choice of catalyst to be any metal or oxide provided that the material is electrically conductive. In this poster presentation, we will present studies based on these two classes: (1) Programmable Metals and (2) Programmable Solid Acids (Oxides). Overall, temperature programmed desorption / surface reaction performed on these devices revealed that voltage modulation up to ±10V shifted peak temperatures of adsorbates/products by up to ΔT_peak~±50 ⁰C relative to the uncharged film. The electronic and physical properties of these devices were also successfully characterized by TEM, SEM, UPS, XPS and more. These results indicate that continuous and fast electronic control of semiconductor-like oxides or metals can be achieved with the catalytic condenser device.