(184f) Growth of High Surface Area Titanium Carbide Films

High-surface area catalytically active films can be synthesized by glancing angle deposition of a metal onto a cold surface in a low ambient pressure of gas. The subsequent surface reaction of the two components results in the growth of nano-porous films with controllable stoichiometry and morphology. We have employed this technique, referred to as reactive ballistic deposition (RBD), to deposit nano-structured, high surface area films of titanium carbide.

It is well known that transition metal carbides have catalytic properties similar in some respects to platinum group metals, with the added benefits of comparatively low cost, high thermal stability, and mechanical durability. Building on our knowledge from the previous investigation of high surface area TiO2 films, we are developing high surface area, porous, transition metal carbide films for the purpose of studying their physical properties and chemical reactivity. Our current work has focused on the deposition and physical characterization of titanium carbide (TiC) films deposited using the RBD technique. Auger electron spectroscopy is used to investigate the stoichiometric dependence of the films on growth conditions. The specific surface area and distribution of binding site energies of the films are measured as functions of growth temperature, deposition angle, and annealing conditions using temperature programmed desorption (TPD) of chlorodifluoro-methane. Results from TPD studies suggest that TiC films grown using the RBD technique have specific surface areas of at least 200 m2/g and are thermally stable to nearly 1000 K. The combination of high surface area and thermal stability suggest that these films could be effectively utilized for heterogeneous catalysis.