Iron-/Nitrogen-Doped Electrocatalytically Active Carbons for the Oxygen Reduction Reaction with Low Amounts of Cobalt

Abstract

Transition-metal-doped carbon catalysts are promising Pt-free alternatives for low-temperature fuel cells. They are frequently obtained from sacrificial N-rich zeolitic imidazolate frameworks (ZIFs) doped with Co and Fe. The optimal low loading of metals has to be achieved to guarantee the competitive efficiency and facilitate an inquiry into the mechanism of their catalytic activity. We report on microwave-assisted solvothermal synthesis of Zn,Co-ZIFs with a relatively low (1–15 mol %) Co loading, which were further enriched with Fe(II). Materials were pyrolyzed at 700 °C to form catalytically active carbons bearing metal nanoparticles confined in structured carbon. The electrochemistry test of carbons for the oxygen reduction reaction (ORR) in perchloric acid demonstrated their high efficiency even at low cobalt contents. The initial loading of 10 mol % was found efficient, leading to the production of catalytically active carbons allowing for four-electron path of ORR.

Environmental Technologies to Treat Rare Earth Element Pollution: Principles and Engineering

“…Unfortunately, rapid degradation and slow reaction kinetics substantially reduce the rate of commercialization of low-temperature FCs (Guterman et al, 2009(Guterman et al, , 2014. To mitigate these drawbacks, the following approaches have been tried: forming platinum alloys with d-metals (Gudko et al, 2009;McKeown & Rhen, 2018), control over the NPs size and shape (Chen et al, 2014(Chen et al, , 2020, formation of the core-shell (Alinezhad et al, 2020), Pt-skin or skeleton (Stamenkovic et al, 2006) and yolk (Ao et al, 2018) structures, preparation of PGM-free catalysts like Fe/N/C (Wan et al, 2019), Co/N/C (Haile et al, 2021;Li et al, 2019), Fe/Co/N/C (Lastovina et al, 2018b;Pimonova et al, 2019aPimonova et al, , 2019b, metal-free carbons, transition metal carbides (Guil-López et al, 2010) and nitrides (Abdelkareem et al, 2020) and ternary catalysts (Antolini, 2007).…”

The Oxygen Reduction Activity of Nitrogen-doped Graphene

“…The regular structure and semiconductor properties of graphene limit its regulated space, so the effective properties of graphene performance can be improved by introducing other elements through chemical doping. At the same time, heteroatomic doped carbon catalysts can improve its ORR activity and chemical stability 3 . Chemical doping can also change the internal structure of graphene, e.g.…”

Pyridinic-Type N-Doped Graphene on Cobalt Substrate as Efficient Electrocatalyst for Oxygen Reduction Reaction in Acidic Solution in Fuel Cell

“…On the one hand, many experimental and computational works have been done to reduce platinum loading. − On the other hand, nonprecious electrocatalyst materials exhibited comparable activity to platinum. − Among various nonprecious electrocatalyst materials explored, a great attention has been given recently to heteroatom-doped carbon material catalysts because of their low price and earth abundance of raw material, high catalytic ORR activity, high chemical stability, and environmentally friendly. , …”

“…10−14 Among various nonprecious electrocatalyst materials explored, a great attention has been given recently to heteroatom-doped carbon material catalysts because of their low price and earth abundance of raw material, high catalytic ORR activity, high chemical stability, and environmentally friendly. 15,16 The N-doped carbon has demonstrated excellent performance in an alkaline medium as compared to the activity of platinum. 17 It is well-known that a nitrogen dopant embedded in a carbon structure facilitates the adsorption of oxygenated species on adjacent carbon atoms, rather than acting directly as an adsorption site.…”