Comparative Study of Different Electrochemical Techniques for the Preparation of Supported Pt-Ru Catalysts

Abstract

Bimetallic Pt-Ru particles supported on glassy carbon rods were synthesized by simultaneous electrochemical deposition. Pt-Ru alloy particles were deposited from a dilute aqueous acid solution of chloroplatinic acid and ruthenium trichloride by different electrochemical techniques: (i) coulostatic deposition at constant potential; (ii) double potentiostatic steps; and (iii) multiple cycles of potentiostatic pulses. It was found that particle size distribution, and the morphology and composition of the deposits strongly depend on the deposition method. Scanning electron microscopy images showed the presence of agglomerates with diameters in the submicrometre scale composed of nano-sized particles. The catalysts prepared by multiple cycles of potentiostatic pulses exhibited better activity for methanol oxidation and enhanced tolerance to CO poisoning compared with those prepared by the other techniques. This behaviour could be associated with the structure containing a high number of defects of the particles and a higher ruthenium content in the solid solution.