Microwave-assisted synthesis of Pt/C catalyst at high temperatures for PEM fuel cells

Abstract

In this work, Vulcan XC-72 supported platinum electrocatalysts (Pt/C) are synthesized by using a two-step, microwave-assisted polyol method. The effect of synthesis conditions on the properties of Pt/C electrocatalysts is investigated at various temperatures (140–200 °C) and corresponding autogenous-pressures (1.0–7.5 bar) at a constant synthesis duration of 35 min. A completely sealed reaction vessel is used to heat the polyol mixture above its boiling point of 140 °C. Catalysts are characterized by XRD, TGA, FTIR, BET, SEM, TEM, Cyclic voltammetry (CV), and the results are compared with the properties of commercial Pt/C. Pt/C catalyst synthesized at 160 °C exhibits the highest ECSA of 69.2 m2/g Pt, highest Pt loading efficiency of 92%, narrowest Pt particle size distribution with an average of 3.6 nm, and Pt crystallite size of 2.3 nm. SEM and TEM confirm the formation of micron-sized Pt agglomerations for the catalysts synthesized at 180 and 200 °C. Characterization studies show that the polyol method presented in this study is suitable for synthesizing Pt/C catalysts which have comparable properties to commercial Pt/C.