Sb-Doped SnO2 Aerogels Based Catalysts for Proton Exchange Membrane Fuel Cells: Pt Deposition Routes, Electrocatalytic Activity and Durability

G Ozouf,C Beauger,L Guétaz,F Maillard,M Chatenet,G Cognard,M Heitzmann,P A Jacques

doi:10.1149/2.0041806jes

Abstract

Tin dioxide is a promising catalyst support to improve the stability of proton-exchange membrane fuel cells (PEMFC) cathodes at high voltages. However, optimizing the catalytic activity for the oxygen reduction reaction (ORR) of tin dioxide based electrocatalyst still remains challenging. In this study, an antimony doped tin dioxide (ATO) aerogel featuring suitable physico-chemical properties for application at a PEMFC cathode was successfully synthetized. Two platinum nanoparticles deposition methods were tested and compared. One is a chemical reduction route (using ethylene glycol, EG), the other uses ultraviolet (UV) irradiation followed by different thermal post-treatments. Electrocatalysts structure and morphology were analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) experiments. The highest ORR mass activity measured in liquid electrolyte at 25°C was obtained for Pt/ATO from EG method (32 A gPt−1 versus 27 A gPt−1 for a reference Pt/HSAC 40 wt%). Pt/ATO turned out to be more stable than Pt/HSAC during an accelerated stress test composed of 5,000 potential cycles between 1.0 and 1.5 V vs. RHE at 80°C.

Highlights

The efficiency of the two deposition protocols was evaluated by considering i) the structure and the morphology of the Pt nanoparticles (XRD, HRTEM and HAADF/STEM), ii) the specific surface area (SPt) and iii) the electrocatalytic activity for the oxygen reduction reaction (ORR) measured in rotating disk electrode (RDE) configuration
ATO aerogel-based electrocatalysts were prepared using two Pt nanoparticle deposition methods starting from the same Pt salt precursor (H2PtCl6)
The Pt specific surface area reaches 32 m2 gPt−1, about half of that measured for the Pt/HSAC taken as reference (SPt = 72 m2 gPt−1)

Summary

Introduction

The efficiency of the two deposition protocols was evaluated by considering i) the structure and the morphology of the Pt nanoparticles (XRD, HRTEM and HAADF/STEM), ii) the specific surface area (SPt) and iii) the electrocatalytic activity for the oxygen reduction reaction (ORR) measured in RDE configuration. Electrochemical measurements.—The Pt specific surface area (SPt) and the ORR mass activity (MA0.9V) at E = 0.9 V vs RHE of different Pt/ATO aerogel samples were determined in RDE configuration and benchmarked to those of Pt/HSAC.

Results

Conclusion