Iron polyphthalocyanine-derived ternary-balanced Fe3O4/Fe3N/Fe-N-C@PC as a high-performance electrocatalyst for the oxygen reduction reaction

Abstract

The oxygen reduction reaction (ORR) is the cornerstone reaction of the cathode in metal-air batteries; however, slow kinetics requires high-performance catalysts to promote the reaction. Polyphthalocyanine (PPc) has a typical chemical cross-linking structure and uniformly dispersed metal active sites, but its poor activity and conductivity limit its applications as an ORR catalyst. Herein, a manageable and convenient strategy is proposed to synthesize ternary ORR catalysts through the low-temperature pyrolysis of FePPc. The optimal catalyst, Fe 3 O 4 /Fe 3 N/Fe-N-C@PC-2.5, exhibits excellent ORR activity in alkaline solution with a half-wave potential of 0.90 V, which is significantly higher than that of commercial 20% Pt/C (0.84 V). Electrochemical tests and extended X-ray absorption fine structure spectroscopy reveal that the superior ORR activity of Fe 3 O 4 /Fe 3 N/Fe-N-C@PC-2.5 could be ascribed to the balance of its ternary components (i.e., Fe 3 O 4 , Fe 3 N, and Fe-N 4 species). A Zn-air battery incorporating Fe 3 O 4 /Fe 3 N/Fe-N-C@PC-2.5 as an air cathodic catalyst delivers a high open-circuit voltage and peak power density. During galvanostatic discharge, the battery demonstrates a specific capacity of 815.7 mA h g −1 . The facile strategy of using PPc to develop high-performance composite electrocatalysts may be expanded to develop new types of catalysts in the energy field.

Metal-coordinated porous polydopamine nanospheres derived Fe 3N-FeCo encapsulated N-doped carbon as a highly efficient electrocatalyst for oxygen reduction reaction

“…Among various non-precious electrocatalysts, transition metal nitrides incorporated carbon materials (MNx-C) have become prospective alternatives to replace Pt-based precious electrocatalysts owing to their high conductivity, economical cost and intriguing ORR performance [7,8]. Particularly, FeN3-decorated carbon materials (Fe3N-C) demonstrated comparable ORR activity to Pt/C [9,10], and FeN3 nanoparticles have been substantiated to be genuine active species toward ORR [11]. However, the inevitable aggregation of FeN3 during the reaction can obviously decrease its activity and stability.…”

3D Fe3O4-decorated Nitrogen-doped Graphene Aerogel as a Highly Durable Electrocatalyst for Oxygen Reduction Reactions

“…The absence of satellite peaks demonstrates that the Fe species is present as Fe3O4 in the catalyst [14,24,32]. The O 1s spectrum (Figure 4d) can be divided into three peaks appearing at the binding energies of 530.5 (Fe-O), 532.1 (O-C =O), and 533.56 eV (C-OH) [33]. The analysis of the XPS profiles demonstrates the presence of Fe3O4 and the successful doping of N into graphene.…”

Anchoring Highly Dispersed Pt Electrocatalysts on TiOx with Strong Metal–Support Interactions via an Oxygen Vacancy-Assisted Strategy as Durable Catalysts for the Oxygen Reduction Reaction

“…The D band of PTO-V o -H/C negatively shifts 15.8 cm –1 when compared with TiO 2 -V o /C, which indicates the more defects induced by oxygen vacancies in PTO-V o -H/C after Pt deposition and H 2 reduction. The higher intensity ratio of D-band to G-band for PTO-V o -H/C ( I D / I G = 1.15) indicates a higher degree of defects or disorder, which is related to the composite supports and further promotes the ORR . Moreover, the peaks around 400, 520, and 620 cm –1 correspond to the symmetrical stretching mode of TiO 2 and oxygen vacancies, respectively. , The magnified spectra (inset of Figure c) shows the peak at 520 cm –1 for PTO-V o -H/C with weaker intensity than that for TiO 2 -V o /C, indicating the anchoring role of oxygen vacancies in the lattice.…”

“…Quick global population growth and numerous consumptions of fossil fuel energy have led to severe environmental pollution and energy crisis; thus, the development of sustainable renewable energies has aroused extensive attention in order to alleviate these phenomena. − Based on the efficient utilization of hydrogen and oxygen, proton exchange membrane fuel cells (PEMFCs) have been deemed as one of the most promising new energy devices with the high energy conversion, low working temperature, fast start, and environmental sustainability. − The sluggish catalytic kinetic of the oxygen reduction reaction (ORR) occurs in the cathode of PEMFCs, which limits the efficiency and application of the large-scale practical applications. − At present, platinum (Pt)-based catalysts are widely acknowledged as the first choice for ORR. However, the scarcity and high cost of Pt also hamper the further widespread implementation for PEMFC applications. − Moreover, the working condition of PEMFCs, including high potential and strong acidity, exerts great influence on durability of electrocatalysts .…”