Synthesis of Pt-immobilized on silica and polystyrene-encapsulated silica and their applications as electrocatalysts in the proton exchange membrane fuel cell

Abstract

Nano sized Pt particles were successfully immobilized onto SiO2 and polystyrene-encapsulated silica core shell (SiO2@PS). To make the immobilization of Pt onto both silica and polystyrene-encapsulated silica core shell, SiO2 was first functionalized with -NH2 using 3-amino propyl trimethoxysilane (APTMS) while for core shell, the negatively charged surface of polystyrene (PS) was changed with positive charge by cationic surfactant such as cetyltrimethylammonium chloride (CTACI) to make the formation of SiO2 shell on preformed PS sphere. Transmission electron micrograph (TEM) images shows that Pt nanoparticles immobilized onto SiO2 and SiO2@PS were to be 3-4 nm without agglomeraiton. The energy dispersive spectroscope (EDS) shows that Pt contents on both SiO2 and SiO2@PS were to be 21.45% and 20.28%, respectively. In case of Pt-SiO2@PS, it is believed that Pt should have been immobilized onto PS surface and pore within SiO2 shell as well as SiO2 surface. The MEA fabricated with Pt-SiO2@PS shows better cell performance than of Pt-SiO2.