Electrochemical preparation and characterization of Pt particles on ITO substrate: Morphological effect on ammonia oxidation

Pt particles with different surface morphology (spherical, flower-like or sheet-like) were successfully deposited on the ITO substrate by controlling the deposition current density using the electrochemical deposition method. The prepared Pt/ITO electrodes were characterized by scanning electron microscopy, inductively coupled plasma, X-ray diffraction and cyclic voltammetry. The results showed that the fabricated Pt/ITO electrode can be successfully used for the electro-oxidation of ammonia. Furthermore, the surface morphology of the Pt particles on the ITO substrates has a significant influence on the electrocatalytic activity for ammonia oxidation. The flower-like and sheet-like Pt particles have a much higher electrocatalytic activity for ammonia oxidation than the smooth spherical Pt particles. The high electrocatalytic activity of the former is not only due to their larger electrochemical active surface area, but also due to their special morphology. There are many tips or edges on the surface of the flower-like or sheet-like Pt particles which may contribute to their high electrocatalytic activity per unit electroactive surface area, as confirmed by the electrochemical tests.