The effect of rapid thermal annealing on sputtered Pt and Pt3Pd2 thin film electrocatalysts for aqueous SO2 electro-oxidation

Abstract

Insight into the effect that rapid thermal annealing (RTA) has on the structural and electrochemical characteristics of sputtered Pt and Pt3Pd2 thin film electrocatalysts is communicated. The DC magnetron sputtered thin films were rapidly annealed at temperatures ranging from 600 to 900 °C under an Ar atmosphere. The microstructural changes and electrochemical properties (onset potential, current density and stability) induced by rapid thermal annealing were investigated towards the electro-oxidation of aqueous SO2. An increase in annealing temperature induced different degrees of crystallinity, and the surfaces changed from being smooth and granular to surfaces exhibiting defined grain boundaries. Electrochemical characterisation, employing linear polarisation (LP) and cyclic voltammetry (CV), revealed improved catalytic activity for the Pt3Pd2 thin film catalysts (compared to Pt) exhibiting lower onset potentials, competitive currents and acceptable stability. The Pt3Pd2 thin film, annealed at 800 °C, proved to be a promising contender in competing with pure Pt towards the electro-oxidation of aqueous SO2