Fe-containing polyimide-based high-performance ORR catalysts in acidic medium: a kinetic approach to study the durability of catalysts

Abstract

The ORR activity and durability of Fe-containing non-precious N-doped carbon catalysts in acidic medium were studied using a rotating ring-disk electrode voltammetry and XPS technique.

One step synthesis of chlorine-free Pt/Nitrogen-doped graphene composite for oxygen reduction reaction

“…The slopes in the high current density region were 150, 142, 147, and 120 mV/decade for the same samples. These values are comparable with those reported in the literature for similar systems, which implies that the rate determining step is the same for every electrode in this region [9,[58][59][60]. When the slope of the polarization curve is around 60 mV/decade, the electrode surface is under Temkin adsorption conditions.…”

Degradation by Hydrogen Peroxide of Metal-Nitrogen-Carbon Catalysts for Oxygen Reduction

“…This degradation mechanism can probably not be dealt with at a system level and is therefore an inescapable issue for Me-N-C catalysts. While the % H 2 O 2 produced during ORR is often not much higher on Fe(Co)-N-C than on Pt/C catalysts, [25][26][27][33][34] 33,37 The important difference between the durability of Pt/C and Fe(Co)-N-C catalysts in PEMFC may thus stem from their different reactivity toward H 2 O 2 . Moreover, chemical disproportionation of H 2 O 2 on Fe(Co)-N-C catalysts via Fenton chemistry might produce a significant amount of radical oxygen species (ROS).…”

“…A restricted number of studies have focused on the degradation mechanisms of Fe(Co)-N-C catalysts. [15][16][17][18][19][20][21][22][23][24][25][26][27][28] Fe-N-C catalysts pyrolyzed in NH 3 have shown the highest initial activity and power performance thus far, but degrade very quickly in PEMFC, mostly due to a protonation and anion-binding effect of highly-basic surface N-groups that are characteristic of NH 3 pyrolysis. 16 Fe(Co)-N-C catalysts synthesized at high temperature in inert gas are initially less active but are more stable in PEMFC.…”

Morphology-Controlled Nitrogen-Containing Polymers as Synthetic Precursors for Electrochemical Oxygen Reduction Fe/N/C Cathode Catalysts

“…Indeed, Olson et al proposed a bi-functional ORR mechanism over Fe/N/C catalysts in 2010 [25], but quantitative discussion to resolve the quasi-four-electron reduction reaction proved difficult. While Ohsaka and co-workers tried to apply the Damjanovic-Hsueh approach [21,26], which involves detailed RRDE analysis by plotting of the obtained parameters against the rotation speeds, such analysis relying on rotation speeds suffered from huge noise [27,28]. To address these concerns, Nabae and co-workers recently developed a new model (Figure 2b) and method for RRDE analysis [29].…”

“…In this context, as shown in Figure 3, a hybrid mechanism is worth considering for the ORR conducted over Fe/N/C catalysts, where the first two-electron reduction to form H 2 O 2 is catalyzed by metal-free N/C catalytic centers and the following two-electron reduction of H 2 O 2 and/or the direct four-electron reduction of O 2 to form H 2 O are catalyzed by Fe/N/C-based catalytic centers. from huge noise [27,28]. To address these concerns, Nabae and co-workers recently developed a new model ( Figure 2b) and method for RRDE analysis [29].…”