nz8b00516_si_001.pdf (1.63 MB)
Suppression Effect of Small Organic Molecules on Oxygen Reduction Activity of Fe/N/C Catalysts
journal contribution
posted on 2018-05-18, 00:00 authored by Yu-Cheng Wang, Yu-Jiao Lai, Li-Yang Wan, Hong Yang, Jiao Dong, Long Huang, Chi Chen, Muhammad Rauf, Zhi-You Zhou, Shi-Gang SunPyrolyzed
Fe/N/C catalysts have high selectivity for catalyzing
the oxygen reduction reaction (ORR) and exhibit no activity toward
the electrooxidation of small organic molecules (SOMs). As such, their
tolerance toward SOMs has rarely been questioned. Unexpectedly, we
found that SOMs can greatly suppress the ORR activity of microporous-type
Fe/N/C catalysts in alkaline medium. Such a suppression effect is
strengthened as molecular polarity decreases or molecular weight increases
and can be attributed to the blockage of micropore transport channels
for ORR-related species by SOM adsorption. Interestingly, such a suppression
effect by micropore filling disappears in the acidic medium. High
tolerance to SOMs in acidic medium is attributed to the protonation
of pyridinic-N, which increases the polarity of the micropore surrounding
and inhibits the adsorption of low-polarity SOMs. This study is helpful
to guide the synthesis of porous Fe/N/C electrocatalysts, especially
when they are applied in an alkaline medium.