Synthesis, Purification, and Electrocatalytic Activity of Platinum Nanocatalyst with Globular Dendritic Structure

A new Pt nanocatalyst was synthesized by chemical reduction of K sub(2)PtCl sub(4) by ascorbic acid in the presence of a non-ionic surfactant Brij-35 (CH sub(3)(CH sub(2)) sub(10)CH sub(2)(OCH sub(2)CH sub(2)) sub(23)OH) in aqueous solution at room temperature. The obtained Pt nanocatalyst was characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDX), X-ray powder diffraction, thermogravimetry (TG), and cyclic voltammetry (CV). The uniform Pt nanocatalyst possesses a globular dendritic morphology with a mean diameter of 36.9 nm. The branches of the globular dendrites are 2-4 nm in diameter and 4-6 nm in length. A simple purification method with multiple water washing was developed to remove Brij-35 and other by-products from the surface of Pt nanocatalyst. TG, EDX, and CV results show that the surface of Pt nanocatalyst after purification is as clean as that of commercial Pt black (fuel cell grade, 99.9%). Compared with commercial Pt black, Pt nanocatalyst demonstrates a hi