The Potential of Non Carbon Based Catalysts for Automotive Fuel Cells

Abstract

In this paper we compare the performance and stability of state of the art carbon based catalysts with non carbon based catalyst. Technically Iridium-Oxide supported Platinum exhibits excellent stability under corrosion at 1.4V, with good transport properties and activity in a fuel cells electrode. However for commercial success there is a need for replacing Iridium. As one potential example we have prepared Antimony doped Tin-Oxide supported Platinum. This material is showing fundamentally promising properties, but instability of the dopant leads to a reduction in activity of the catalyst.

Highly Stable PEMFC Electrodes Based on Electrospun Antimony‐Doped SnO2

“…Although the performance of the Pt/Sb–SnO 2 –MEA is still lower than the Pt/C‐based MEA (maximum power density of 0.96 W cm −2 ), this result clearly identifies the support conductivity as one of the main factors driving MEA performance. Another possible reason for the reduced activity compared to the Pt/C‐based MEA could be dissolution of antimony, which could poison the surface of platinum, as observed by Suchsland et al . Nevertheless, the results obtained after the accelerated stress test (AST; Figure described below) seem to exclude this scenario.…”

“…[10,40,53,62] The remaining challenge is to overcomei st he increase fuel cell performance,w hichi ss till lower than that obtained for Pt/C MEAs. Further studies are in progress to verify the stabilityo fA TO under PEMFC operating conditions, which has already been suggested as ap ossible issue relatedt ot his reduced activity, [49][50][51] andm eets this challenge and proposes ar eal alternative to carbon supports.…”

“…[48,49] It has been already demonstrated that the stability of the antimony-doped SnO 2 is not an intrinsic characteristic of the material, but instead strongly dependso nt he synthesis conditions, which are related to the antimony ion concentration at the surface. [47] This explainst he certain instability of ATO-based electrodes (Sn or Sb dissolution) reported by somer esearch groups, [49][50][51] whereas, in other cases, potentials as high as 1.8 V could be reached without degradation. [52] In this work, SnO 2 loose-tubes with different amount of antimony (at %) were obtained through electrospinning and subse-High durability and activity for the oxygen reduction reaction were demonstrated for oxide-supported platinum catalysts.…”

“…It seems that the stabilityo ft he ATOs upport is not compromised,asr eported elsewhere. [49][50][51] As ar esult of the improved conductivity of the catalyst layer, MEAs integrating ATO-based cathodes provide significantly higherp erformances than Nb-SnO 2 based MEAs. Although, they offer al ower maximump ower density compared to Pt/C-…”

Particle-Support Interferences in Small-Angle X-Ray Scattering from Supported-Catalyst Materials

“…The absolute calibration of the photodiode measuring the transmitted photon current is done with a glassy carbon standard [18]. The investigated catalyst consists of platinum nanoparticles supported on iridium-titanium oxide (Pt=IrO 2 -TiO 2 ) and is provided by Umicore AG & Co. KG [19]. The Pt content is 8.8 wt %, and the support oxide consists of two separate phases of IrO 2 (≈66 mol%) and TiO 2 (≈34 mol%).…”