Synthesis of carbon-supported Pt nanoparticle electrocatalysts using nanocrystalline cellulose as reducing agent

Abstract

Pt nanoparticles have been synthesized at relatively low temperatures in aqueous solution from hexachloroplatinic acid using cellulose nanocrystals (CNXLs) from cotton as reducing agents. The Pt nanoparticles were characterised using X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis. X-ray diffraction and X-ray photoelectron spectroscopy showed that the particles have a metallic Pt core and an oxidised surface layer. TEM analysis showed that the nanoparticles have an average diameter of approximately 2 nm, which is independent of the reactant concentrations. By performing the reduction reaction in the presence of a carbon-black support (Vulcan XC-72R), and removing the cellulosic material by heating in air, it was possible to produce carbon black supported Pt nanoparticles. Electrochemical analysis revealed that this Pt/C was highly active towards electrocatalysis of the oxygen reduction reaction, suggesting that this method may be very useful for fabricating Pt/C electrocatalysts.