Theoretically probing the possible degradation mechanisms of an FeNC catalyst during the oxygen reduction reaction

Abstract

For FeNC catalyst widely used in oxygen reduction reaction (ORR), its instability under Fuel Cells (FCs) operating condition has become the biggest obstacle to the practical application. The complexity of...

Exploring Durable Single-Atom Catalysts for Proton Exchange Membrane Fuel Cells

“…However, they later abandoned this hypothesis because the decay behaviors were found not sensitive to the properties of the proton providers . Very recently, Wei and co-workers associated protonation with demetalation . On the basis of theoretical calculations, they identified a fragile intermediate of *Fe­(OH) 2 that was vulnerable to N protonation during the ORR.…”

“…52 Very recently, Wei and co-workers associated protonation with demetalation. 53 On the basis of theoretical calculations, they identified a fragile intermediate of *Fe(OH) 2 that was vulnerable to N protonation during the ORR. The protonation of N (*Fe(OH) 2 −(NH) 2 ) would weaken Fe−N bond and ultimately result in demetalation in the form of Fe(OH) 2 .…”

Vicinal Co atom-coordinated Fe–N–C catalysts to boost the oxygen reduction reaction

“…According to the work by Li et al , 25 the formation of *Fe(OH) 2 , which is a structure of two OH* species adsorbed on the same side of Fe, is the main reason for Fe site leaching and irreversible activity decline. Here, the structure of *Fe(OH) 2 was named *2OH Fe , and the free energy of *2OH Fe formation was calculated over these two catalytic models.…”

“…The results reveal that the *Fe(OH) 2 intermediate is easily formed by the adsorption of OH species on the same side of the Fe–N 4 site, which could result in the successive protonation of N and permanently damage the Fe–N 4 moiety, leading to the leaching of Fe. 25 Thus, strong adsorption of ORR intermediates on the Fe center is primarily responsible for the Fe dissolution and deactivation of the Fe–N–C catalyst. In this regard, weakening the adsorption of ORR intermediates on the Fe site to stabilize the Fe–N structure might be a feasible route to effectively improve the durability of Fe–N–C catalysts.…”

Enhancing the ORR activity of fullerene-derived carbons by implanting Fe in assembled diamine–C60 spheres

“…Another is the reduction of O 2 to hydrogen peroxide (H 2 O 2 ) via a two-electron (2e − ) process. 44 Based on the Koutecky–Levich (K–L) equation, the electron transfer number ( n ) can be estimated. As shown in Fig.…”