Fabrication of Large Area Metal-on-Carbon Catalytic Condensers for Programmable Catalysis

Catalytic condensers stabilize charge on either side of a high-k dielectric film to modulate the electronic states of a catalytic layer for electronic control of surface reactions. Here, carbon sputtering provided for fast, large-scale fabrication of metal-carbon catalytic condensers required for industrial application. Carbon films were sputtered on HfO2 dielectric/p-type Si with different thickness (1, 3, 6, 10 nm), and the enhancement of conductance and capacitance of carbon films was observed upon increasing carbon thickness following thermal treatment at 400 °C. After Pt deposition on the carbon films, the Pt catalytic condenser exhibited high capacitance of ~210 nF/cm^2 that was maintained at a frequency ~1,000 Hz, satisfying the requirement for a dynamic catalyst to implement catalytic resonance. Temperature programmed desorption of carbon monoxide yielded CO desorption peaks which shifted in temperature with varying potential applied to the condenser (−6 V or 6 +V) indicating a shift in the binding energy of carbon monoxide on the Pt condenser surface. A substantial increase of capacitance (~2,000 nF/cm^2) of the Pt-on-carbon devices was observed at elevated temperatures of 400 °C that can modulate ~10% of charge per metal atom when 10 V potential was applied. A large catalytic condenser of 42 cm^2 area Pt/C/HfO2/Si exhibited high capacitance of 9,393 nF with low leakage current/capacitive current ratio (<0.1), demonstrating the practicality and versatility of the facile, large-scale fabrication method for metal-carbon catalytic condensers.