Alumina-Titania Nanolaminate Condensers for Hot Programmable Catalysis

Abstract

For programmable catalysis applications, nanolaminates composed of thin alternating layers of alumina and titania (ATO) were engineered using atomic layer deposition (ALD) as the dielectric material for a Pt-on-carbon catalytic condenser. Systematic investigation assessed synthesis parameters such as deposition temperature, alumina and titania layer thicknesses, the total number of layers (and interfaces), and the presence of a capping alumina layer on the maximum achievable charge accumulation in the Pt catalyst layer. The highest capacitance ATO configuration demonstrated a specific capacitance of ~1,200 nF/cm2 with working voltages of ±5 V, enabling the storage of 4×10^13 electrons or holes per cm2 at room temperature. Adsorption of carbon monoxide on the Pt/C-ATO device characterized by grazing incidence infrared spectroscopy showed changes in the surface binding energy of 13.1 ± 0.8 kJ/mol for an applied external voltage bias of ±1 V. The results enhance our understanding of nanolaminate structures and provide a method for increasing charge condensation strength for higher temperature surface chemistries.