Self-Anchored Platinum-Decorated Antimony-Doped-Tin Oxide as a Durable Oxygen Reduction Electrocatalyst

Abstract

The lifetime of commercial proton exchange membrane fuel cells (PEMFCs) is circumscribed by the insufficient durability of commercial catalysts. The use of metal oxide supports in place of carbon significantly increases electrocatalyst durability. Herein, following density functional theory predictions of improved platinum (Pt) stability on antimony-doped tin oxide (ATO) supports, we synthesized ATO whose morphology and crystal structure were engineered using a Pt-anchoring technique. X-ray photoelectron spectroscopy indicated that the Pt anchor sites aided in the reduction of Pt precursors to Pt on the ATO surface. X-ray absorption near-edge spectroscopy revealed the existence of strong metal–support interactions (SMSIs) between Pt and ATO. The combination of SMSIs and high control over Pt dispersion enabled the Pt/Pt-aerogel-ATO (Pt supported on aerogel ATO with Pt anchor sites) electrocatalyst to achieve 2 × the area-specific activity of Pt/C in ex situ testing. In a H2/air PEMFC, Pt/Pt-aerogel-ATO cathodes enabled 20% higher peak power density and <1/6 the loss of active surface area as compared to Pt/C. In a PEMFC under rigorous potential cycling, the Pt/Pt-aerogel-ATO retained its initial peak power density as opposed to a 58% loss for Pt/C. Furthermore, cost models indicate that Pt/Pt-aerogel-ATO is 26% less expensive than Pt/C over its useful lifetime.

Acidic oxygen evolution reaction: Mechanism, catalyst classification, and enhancement strategies

“…As an alternative to carbon materials, metal oxides are regarded as promising substrate materials due to their good corrosion resistance and interaction with surface-supported noble metals. [206,207] For example, Nb-doped TiO 2 (ATO) could be tightly connected to the amorphous IrO 2 particles on its surface and had a small face resistance (Figure 16E). [203] Moreover, the ATO substrate enabled lower oxidizability of iridium on the surface (Figure 16B,C).…”

Design of advanced aerogel structures for oxygen reduction reaction electrocatalysis

“…In order to increase the durability, some treatments have been done with aerogels, for example, heat treatments, chemical treatments (HNO 3 , H 2 SO 4 , etc. ), or use of carbon‐free aerogels 82 …”

“…), or use of carbon-free aerogels. 82 One possible treatment is to protect the carbon with a thin metal oxide coating. A thin layer of coating can, on one hand, keep the main morphology and the electrical properties of carbon underneath, and on the other hand, provide better resistance for corrosion.…”

Lens-Shaped Carbon Particles with Perpendicularly-Oriented Channels for High-Performance Proton Exchange Membrane Fuel Cells

“…Proton exchange membrane fuel cells (PEMFCs) are considered promising power sources for achieving eco-friendly energy conversion. − However, the sluggish oxygen reduction reaction (ORR) requires a vast amount of scarce or expensive catalysts such as platinum (Pt) and has been a major hurdle for the commercialization of PEMFCs. − Thus, a great amount of effort has been devoted toward developing a highly active system with low Pt usage or Pt-free catalysts. − Nonetheless, the relatively thick catalyst layer is required to reduce Pt weight fraction, which severely impedes mass transport of reactants and products, limiting the PEMFC performance. − Although the introduction of pores inside carbon particles can increase the surface area, − it is essential to control the channel structures in terms of size and connectivity in the cathode to enhance the mass transport efficiency …”