Sb-Doped SnO₂Aerogels Based Catalysts for Proton Exchange Membrane Fuel Cells: Pt Deposition Routes, Electrocatalytic Activity and Durability

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 g Pt −1 versus 27 A g Pt −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.

Strong Interaction between Platinum Nanoparticles and Tantalum-Doped Tin Oxide Nanofibers and Its Activation and Stabilization Effects for Oxygen Reduction Reaction

“…In Figure 8 The ORR mass (MA) and specific activity (SA) values at 0.9 V vs RHE of Pt deposited on the Ta doped SnO2 fibers and on carbon black and HiSPEC 9100 are listed in Table 5. Pt/1Ta:SnO2 electrocatalysts exhibited the highest specific and mass activities reported for Pt deposited on SnO2 supports doped with Ta [43,45] or other heteroatoms [15,16,43,86,88,89,[23][24][25][26][27]29,30,33]. The specific activity was the same for both Ta:SnO2-based electrocatalysts (640 A cm -2 ) and, in agreement with the different ECSA, the mass activity increased from 307 A gPt -1 for 34Pt/1Ta:SnO2 to 465 A gPt -1 for 7Pt/1Ta:SnO2.…”

“…In order to increase its conductivity, tin oxide is mostly employed in composites with carbon e.g. as a protecting layer preserving the conductivity of the support [19][20][21] or n-doped with pentavalent ions [22] including niobium [23][24][25][26][27][28] and antimony [15,24,[36][37][38]26,[29][30][31][32][33][34][35] providing an extra electron as charge carrier.…”

Current status, opportunities, and challenges in fuel cell catalytic application of aerogels

“…It includes antimony, NiCo 2 O 4 , silicon, and TiO 2 aerogel. Ozouf et al provide aerogel antimony‐doped tin dioxide (ATO) for use as PEMFC cathode electrocatalyst support. The best performance was shown by Pt/ATO with preparation method using ethylene glycol in chemical reduction route.…”

Highly Durable and Active Pt/Sb-Doped SnO2 Oxygen Reduction Reaction Electrocatalysts Produced by Atomic Layer Deposition

“…In addition to identifying suitable supports, the PGM deposition method also plays a crucial role in the activity and durability of the catalyst. Wet chemical methods (e.g., polyol, wet impregnation, and chemical reduction) optimized for Pt dispersion on carbon yield suboptimal results with MMOs due to their lower surface area and lower porosity. − Alternate methods such as ultraviolet (UV) irradiation Pt deposition and organometallic chemical deposition (OMCD) fail to translate into improved ORR activity, and electrodeposition scales poorly. , On the other hand, atomic layer deposition (ALD) using fluidized bed reactors enables large-scale Pt deposit onto MMO supports while the self-limiting surface chemistry intrinsic to the ALD process enables precise control of the particle size of deposited material. − Despite prior success in synthesizing ORR catalysts using ALD, scaling-up and testing of durable MMO supported Pt catalysts in actual PEMFCs are woefully lacking.…”