Fe3C/Fe2O3 heterostructure embedded in N-doped graphene as a bifunctional catalyst for quasi-solid-state zinc–air batteries

Abstract

The development of nonprecious metal catalysts with highly efficient and durable activities is of great importance for high performances of zinc-air batteries. Herein, the N-doped graphene wrapped Fe 3 C/Fe 2 O 3 heterostructure has been designed as a bifunctional oxygen catalyst for zinc-air batteries. In the synthesis process of the catalyst, graphene oxide (GO) can assemble with graphitic carbon nitride (g-C 3 N 4 ) and FeOOH nanorods by the π−π stacking and hydrogen bonds, respectively. The assembly of GO, g-C 3 N 4 and FeOOH nanorods results in nanostructure of carbon layers coated iron species and leads to outstanding durability in both alkaline and acidic media. The synergistic effect of nitrogen doping and Fe 3 C/Fe 2 O 3 heterostructure allows the catalyst (Fe 3 C/Fe 2 O 3 @NGNs) to display high oxygen reduction and evolution reaction activities. The liquid zinc-air battery assembled with the catalyst presented a remarkable peak power density (139.8 mW cm −2 ), large specific capacity (722 mAh g −1 ) and excellent charging-discharging cycling performance. The quasi-solid-state zinc-air battery with the catalyst exhibited an impressive open-circuit voltage and a peak power density. Therefore, the Fe 3 C/Fe 2 O 3 @NGNs catalyst is expected to have a bright future for practical applications in energy conversion devices.

Flocculant-Assisted Synthesis of Graphene-Like Carbon Nanosheets for Oxygen Reduction Reaction and Supercapacitor

“…It is indicated that an excess Fe (III) salt causes the particles of Fe species aggregated during calcination, thereby reducing the SSA. The results indicated that a proper amount of iron can increase the SSA of the materials, which was consistent with previous work [29]. It has been reported that high SSA materials can introduce more active sites to boost ORR activity and supercapacitor performance [30].…”

Highly efficient electrocatalytic hydrogen evolution promoted by O–Mo–C interfaces of ultrafine β-Mo2C nanostructures

“…However, the surface metal atoms of Mo 2 C and other carbide catalysts are easily oxidized in aerobic environments, creating a thin adherent surface oxide layer. 22,23,[27][28][29] In previous reports, the existence of Mo in low and high valence states is commonly observed in Mo 2 C nanomaterials, with Mo 2+ , Mo 4+ and Mo 6+ frequently being seen by XPS. 15,23,[30][31][32][33] The 4+ and 6+ oxidation states generally result from surface oxidation of Mo 2 C, with their role in the HER over Mo 2 C-based catalysts having received little attention to date.…”

d-Orbital steered active sites through ligand editing on heterometal imidazole frameworks for rechargeable zinc-air battery

“…Platinum on carbon (Pt/C) and ruthenium oxide (RuO 2 ) are the respective ORR and OER benchmarks, however, their applications in rechargeable ZABs are not favored due to their scarcity and inferior bifunctionality 7,13 . Previous attempts on economically viable electrocatalysts primarily involve inorganic candidates, such as heteroatom-doped carbon materials, metal compounds or their composites 9,[14][15][16][17][18][19][20][21][22][23][24] . However, their electrocatalytic activity and stability are limited by dissolution or aggregation of inorganic components triggered by corrosion in highly concentrated alkaline electrolytes of oxygen free radicals emerged during battery cycling 3,25,26 .…”