Reaction mechanisms of the O ₂ reduction/evolution reaction

Abstract

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous

Hierarchical oxygen reduction reaction electrocatalysts based on FeSn0.5 species embedded in carbon nitride-graphene based supports

“…The above evidence is rationalized admitting that the ORR mechanism of the proposed ECs is very different with respect to that of the Pt/C ref. The ORR is bottlenecked by the first transfer of electrons from the EC to the dioxygen [10]. At pH = 1, such an electron transfer can only occur through a conventional "inner-shell" process, where dioxygen must undergo direct adsorption on the active sites [12,13].…”

“…On one hand, the identification of the "real" ORR active site for every EC is often difficult; on the other hand, the mechanistic details of the ORR are often studied only superficially, with a particular reference to the role played by the pH of the environment. Since: (i) the latter has a major impact on the ORR mechanism [10,11,27]; and (ii) in different EECS devices, the ORR takes place at a different pH (from 0-1 in the case of protonexchange membrane fuel cells, PEMFCs [28] to [13][14] for anion-exchange membrane fuel cells, AEMFCs [29]), this is a major shortcoming of the state of the art in this field.…”

Perovskite Electrocatalysts for the Oxygen Reduction Reaction in Alkaline Media

“…It is highly recommended to obtain a measurement of background currents in an oxygen-free electrolyte (e.g., by purging with Ar) and to subsequently subtract these currents from the measurement in an oxygen-containing electrolyte to remove double-layer currents and possibly transition metal redox currents [14]. Conceivable reduction products of oxygen (O 2 ) in alkaline media are: superoxide (O 2 − , 1 e − ), hydroperoxide (HO 2 − , 2 e − ) and hydroxide (HO − , 4 e − ) [112]. Hydroxide is the preferred product because the most electrons are transferred per reduced oxygen and due to the very reactive nature of the other products that may corrode cell components [113].…”

Size Effects in Electrocatalysis of Fuel Cell Reactions on Supported Metal Nanoparticles

“…For a discussion of the ORR mechanism in greater detail, see Chapter 9. Despite numerous investigations (see the reviews Tarasevich et al [1983]; Damjanovic [1992]; Kinoshita [1992]; Adzic [1998]; Gattrell and MacDougall [2003]; Durand et al [1996] and references therein), the mechanism of the ORR is still not fully understood. Depending on the electrode material and the reaction conditions, various reaction intermediates may be anticipated, in particular O 2,ad , O À 2,ad , HO 2,ad , O ad , OH ad , and H 2 O 2,ad .…”