Facile Synthesis of Fe₃C@Graphene Hybrid Nanorods as an Efficient and Robust Catalyst for Oxygen Reduction Reaction

Abstract

Robust and efficient catalysts for the oxygen reduction reaction (ORR) are required for the development of various energy storage and conversion devices. In this study, a durable and high‐performance Fe3C@graphene ORR catalyst has been developed by the carbonization of urea‐ and agar‐modified Fe2O3 nanorods. The influence of the carbonization temperature and annealing time on the activity and stability of the resulting Fe/C catalyst was studied in detail. The Fe/C catalyst synthesized at a temperature of 700 °C (holding time: 60 min) showed better ORR activity and improved stability compared to a commercial Pt/C catalyst. The improved ORR catalytic activity of the catalyst is due to its high Fe3C content and its good durability results from the unique microstructure of the Fe3C@graphene hybrid

Nanosized FeS2 Particles Caged in the Hollow Carbon Shell as a Robust Polysulfide Adsorbent and Redox Mediator

“…The typical peak at 284.8 and 287.5 eV can be ascribed to sp 2 hybridized carbon and C–O species, respectively. The peak at 286.3 eV corresponding to C-S bonds proves the covalent bonding between sulfur and carbon shell in the composite. , Another small shoulder peak at 283.2 eV corresponds to Fe–C bond resulting from the Fe 3 C formed during the CVD process. − The Fe 2p 3/2 and 2p 1/2 peaks at 708.1 and 721.7 eV are coupled with their satellite peaks at 713.2 and 727.5 eV (Figure e), respectively, consistent with those of reported FeS 2 . ,, This also confirms the successful sulfurization process from Fe 3 O 4 @C to form FeS 2 @C at 500 °C. The S 2p spectrum (Figure f) demonstrates two peaks centered at 168.8 and 167.4 eV, which can be assigned to the sulfates and sulfites species resulting from the adventitious oxidation of the surface during the sulfurization process. ,, As sulfur and FeS 2 are both included in the electrode, there should be two 2p 3/2 /2p 1/2 doublets in the S 2p spectrum.…”

Fe3C@C/CNT Hybrids Derived from Catalytic Pyrolysis of Lignite: Electrocatalysts for OER

“…The lattice fringes with an outer spacing of 0.34 nm correspond well to the (002) plane of graphitic carbon. 41 The inner layer shows a lattice fringe with a spacing of 0.201 nm, which corresponds well to the (031) plane of Fe 3 C. 42 This further confirms that Fe 3 C nanoparticles are encapsulated in carbon layers and carbon nanotubes. This unique core−shell structure can prevent the agglomeration and dissolution of Fe 3 C particles under certain conditions, while Fe 3 C particles can influence the electronic structure of the surrounding carbon, thus enhancing the catalytic activity of OER.…”

“…The lattice fringes with an outer spacing of 0.34 nm correspond well to the (002) plane of graphitic carbon . The inner layer shows a lattice fringe with a spacing of 0.201 nm, which corresponds well to the (031) plane of Fe 3 C . This further confirms that Fe 3 C nanoparticles are encapsulated in carbon layers and carbon nanotubes.…”

“…The high-resolution XPS spectra of the samples for C 1s, O 1s, and Fe 2p are shown in Figure . In Figure b, the four fitted peaks around 283.9, 284.8, 286.0, and 288.9 eV are considered to be C–Fe, C–C, C–O, and CO, respectively. , In Figure c, it is worth noting that there is no N element in L­(KFeN) either. In Figure d, the high-resolution O 1s spectra can be fitted to three peaks at 529.9, 531.9, and 533.6 eV.…”

MOF@Cellulose Derived Co–N–C Nanowire Network as an Advanced Reversible Oxygen Electrocatalyst for Rechargeable Zinc–Air Batteries

“…Tafel curves of all 3D Co–N–C NN samples are shown in Figure c. Of all the samples, 3D Co–N–C NN-800 demonstrates the highest tafel slope, 83 mV dec –1 , comparable to that of commercial Pt/C (81 mV dec –1 ), indicating a similar catalytic feature toward ORR . We also evaluated the effect of rotating speed on the electrocatalytic activity of 3D Co–N–C NN samples to gain a better understanding on the kinetics of ORR.…”