Electrochemical characterization of nitrogen-incorporated tetrahedral carbon films grown by a filtered cathodic vacuum arc

Tetrahedral carbon films incorporating nitrogen (taC:N) have been produced on Si, Ta, Ti, and electrochemically roughened Ag surfaces using a single commercial filtered cathodic vacuum arc (FCVA) carbon ion source in the presence of nitrogen gas at reduced pressure. Highly resolved Raman spectra under visible laser excitation were obtained for taC:N films only a few nanometers thick deposited on roughened Ag, including the rather elusive T band characteristic of sp³ hybridized bonding. The electrochemical response of taC:N supported on polished Ta in aqueous solutions was virtually identical to that reported earlier for taC:N films on Si prepared by the simultaneous incidence of a custom-made FCVA carbon ion source and a nitrogen ion gun. Reversible kinetics for Ru(NH₃)₆Cl₃ reduction in 1 M KCl and electrocatalytic activity for chlorine evolution and reduction in 1 M HCl solutions are observed juxtaposed to high overpotentials for hydrogen and oxygen evolution.