Organic Additives to Improve Catalyst Performance for High‐Temperature Polymer Electrolyte Membrane Fuel Cells

Abstract

High‐temperature polymer electrolyte membrane fuel cells are promising alternatives to low temperature fuel cells, owing to their higher operating temperatures, which allow for easier water management and enhanced catalytic activity. However, their performance suffers from low oxygen solubility in the electrolyte and phosphoric acid poisoning of catalytically active Pt sites. In this work, we developed new organic additives that provide π‐π stacking of the commercially applied carbon support materials as well as variable substitutable functionalities to interact with the Pt nanoparticles. Different electrochemical methods, such as cyclic voltammetry and linear sweep voltammetry, were performed to test the effect of these organic additives on the onset potential, limiting current, and the number of transferred electrons. It is observed that the limiting currents increase for the additive‐modified Pt/C samples, whereas the onset potential for significant oxygen reduction reaction activity remains unchanged. We conclude that enhanced oxygen solubility at the electrode/electrolyte interface is the reason for the observed behavior.

Influence of Ammonia Contamination on HT-PEM Fuel Cell Platinum Catalyst

“…The effect of ammonium on the ORR activity is presented in Figure 6 (a). The limiting current equal to 4.52 mA cm -2 for blank catalyst obtained from ORR curve is in a good agreement with results of Delikaya et al where similar platinum catalyst with 40 wt.% was also tested in 0.5 mol L -1 H 3 PO 4 (35). This value of current corresponds to the ORR 4-ereduction pathway for all cases.…”

“…Usually at a ECS Transactions, 98 (9) 537-552 (2020) potential of around 0.90 V vs RHE the total current density j depends on limitation of ORR kinetics and oxygen diffusion. In this experiment the mixed kinetic-diffusion region is shifted to the negative potential direction and located at around 0.70 V vs RHE probably due to the presence of phosphate ions of the electrolyte (35).…”

Substitution Pattern-Controlled Fluorescence Lifetimes of Fluoranthene Dyes

“…Fluoranthenes 1–5 (Figure A) were synthesized following a previously published procedure, exploiting the Knoevenagel condensation of 1,2-acenaphthenequinone and a subsequent Diels–Alder cycloaddition reaction with symmetrically and nonsymmetrically functionalized acetylene derivatives. , The differently substituted acetylene derivatives were synthesized by a palladium-catalyzed Sonogashira coupling reaction. The syntheses of the novel 4 and 5 derivatives feature a new synthetic approach to the perfluorinated alkyne, bis (pentafluorophenyl)­acetylene, as described in the Supporting Information (Scheme S1).…”

“…Fluoranthene with the molecular formula C 16 H 10 consists of a naphthalene and a benzene moiety, linked by a 5-membered ring. Applications of these dyes range from additives in polymer electrolyte membrane fuel cells (PEMFCs) over active components in blue-emitting OLEDs , to chemosensors …”

“…Fluoranthene with the molecular formula C 16 H 10 consists of a naphthalene and a benzene moiety, linked by a 5-membered ring. Applications of these dyes range from additives in polymer electrolyte membrane fuel cells (PEMFCs) 36 over active components in blue-emitting OLEDs 37,38 to chemosensors. 39 These dyes feature 2−3 absorption maxima between 200 and 400 nm, which are barely affected by substitution pattern and solvent polarity and a slightly structured emission from about 390 to 650 nm.…”