Preparation and Characterization of Pd-Ti Electrocatalyst on Carbon Supports for Oxygen Reduction

Nanoscale bimetallic Pd-Ti catalysts on carbon supports were prepared in liquid using ammonium tetrachloropalladate and titanium isopropoxide. The size of the metal particles ranged from sub-nanometer to greater than 10 nm, and the X-ray diffraction pattern of metal particles was dominated by a cubic crystalline structure. Depending upon the preparation conditions, the catalysts were comprised of Pd and TiO2 or Pd-3 Ti-like alloy. The surface Ti/Pd ratio was much greater than the original metal loading. We propose that the bimetallic particles were comprised of short-range Pd and TiO2 or Pd-Ti alloy nanocrystal covered by a thin TiO2 layer.