Tolerance of silicon oxide coated Pt/C catalyst towards CO and H₂S contamination in hydrogen for PEMFCs

Platinum on graphitized low surface area carbon (Pt/C) was coated with a silicon oxide (SiO2) thin film and employed as anode catalyst to manipulate the tolerance of proton exchange membrane fuel cells (PEMFCs) towards monoxide (CO) hydrogen sulfide (H2S) contamination. The SiO2 coating, prepared by successive hydrolysis 3-aminopropyl-triethoxisilane (APTES) tetraethoxysilane (TEOS), formed clusters in proximity Pt sizes comparable particles, leaving most surfaces free. performance without CO investigated in-situ at relative humidities (RH) 100, 70 40%. When operated neat hydrogen, SiO2-Pt/C showed marginally better owing an improved protonic conduction due water retaining hydrophilic SiO2. Upon operation contaminated fuel, performed worse than that Pt/C particularly high RH. stripping measurements revealed increase oxidation potential for SiO2-Pt/C, suggesting increased coverage consequently higher overpotentials during fuel. H2S coating extended lifetime until cell voltage broke down, which is attributed enhanced retention solubility sulfuric species. This article protected copyright. All rights reserved.