Ancient Chemistry “Pharaoh’s Snakes” for Efficient Fe-/N-Doped Carbon Electrocatalysts

Abstract

The method of fabricating nonprecious metal electrocatalysts with high activity and durability through a facile and eco-friendly procedure is of great significance to the development of low-cost fuel cells and metal-air batteries. Herein, we present that an ancient chemical reaction of "Pharaoh's snakes" can be a fast and convenient technique to prepare Fe-/N-doped carbon (Fe/N-C) nanosheet/nanotube electrocatalysts with sugar, soda, melamine, and iron nitrate as precursors. The resultant Fe/N-C catalyst has a hierarchically porous structure, a large surface area, and uniformly distributed active sites. The catalyst shows high electrocatalytic activities toward both the oxygen reduction reaction with a half-wave potential of 0.90 V (vs reversible hydrogen electrode) better than that of Pt/C and the oxygen evolution reaction with an overpotential of 0.46 V at the current density of 10 mA cm comparable to that of RuO. The activity and stability of the catalyst are also evaluated in primary and rechargeable Zn-air batteries. In both conditions, three-dimensional Fe/N-C exhibited performances superior to Pt/C. Our work demonstrates a success of utilizing an ancient science to make a state-of-the-art electrocatalyst.

Noble‐free oxygen reduction reaction catalyst supported on Sengon wood ( Paraserianthes falcataria L. ) derived reduced graphene oxide for fuel cell application

“…This finding also agrees with the XRD spectra and the aforementioned O 1s deconvolution peak, which mostly showed a Fe 3 O 4 peak on the catalyst. Apart from the bulky agglomerated surface, the oxide functional group apparently decreased the charge density between active sites, which is indicated by positive shift in the binding energy (higher than 2 eV) of Fe 2p from other work (710 eV) . It is worth noting that the absence of peaks at 707 eV implies successful leaching of the Fe 0 state or Fe particle during acid washing…”

“…The pairing peaks at 711.9 and 725.5 eV are attributed to Fe 2+ 2p, which is present on Fe/N/RGO . Satellite peaks at 719 eV indicate the background spectra of Fe 3 O 4 formation .…”

“…50 The pairing peaks at 711.9 and 725.5 eV are attributed to Fe 2+ 2p, which is present on Fe/N/RGO. 54,55 Satellite peaks at 719 eV indicate the background spectra of Fe 3 O 4 formation. 56 Thus, both Fe 3+ and the background spectra confirm a dominant oxide form, Fe-O, of iron metal on the RGO surface.…”

Synthesis and Active Site Identification of Fe−N−C Single‐Atom Catalysts for the Oxygen Reduction Reaction

“…In most cases, Fe−N−C catalysts are prepared by pyrolyzing a precursor containing iron, nitrogen and carbon elements. Generally, the obtained catalysts possess highly heterogeneous structures with multiple phases including nitrogen‐doped carbons (denoted as N x C y ), nitrogen‐carbon encapsulated bulk iron species (denoted as Fe@N x C y ) and nitrogen coordinated atomic iron moieties imbedded in carbon matrix (denoted as FeN x or FeN x C y ) . All these species contribute to the overall ORR activity thus making this system rather complex .…”

Fe3O4/Nitrogen‐Doped Carbon Electrodes from Tailored Thermal Expansion toward Flexible Solid‐State Asymmetric Supercapacitors

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template-assisted carbonizations, [5,6] electrochemistry deposition, [7] spontaneous gas-foaming, [8] "gel-blowing," [9] "Pharaoh's snakes" reaction, [10] and nanocasting have been developed, and allowing different types of NCMs synthesis from various organic precursors. [11] Although it is possible to obtain desired NCMs with tailored structures and properties by carefully selecting specific procedures, [12] these processes always suffer from removing a template and multi-step operation.

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