Effect of the Oxide–Carbon Heterointerface on the Activity of Co₃O₄/NRGO Nanocomposites toward ORR and OER

Abstract

This work reports the synthesis of Co3O4 particles that can be used as effective electrode materials for both the oxygen reduction (ORR) and evolution (OER) reactions. The development of such catalysts, free from precious group metals and capable of decreasing overpotentials in fuel cells, metal–air batteries, and water electrolyzers, also requires stable supporting and conducting substrates in order to deposit low metal oxide loadings. This challenging approach led us to prepare Co3O4 materials on graphene-based composites more stable than common used Vulcan carbon. Co3O4 particles synthesized from a solvothermal method were thereby deposited onto reduced graphene oxide (RGO) and N-doped reduced graphene oxide (NRGO) prepared from the Hummers method. The structural properties and surface composition of the different materials characterized by X-ray diffraction, transmission electron microscopy, and X-ray induced photoelectron spectroscopy measurements were combined to cyclic voltammetry experiments for revealing the charge transfer from cobalt to nitrogen, which greatly affects the charge acceptance of the surface Co atoms. Electrochemical measurements provided sound evidence of active and stable Co3O4 catalysts toward the ORR and OER.

Preparation and Electrochemical Properties of NiCo2O4 Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

“…For all catalysts, the Co III /Co IV redox transition takes place at potentials higher than 1.50 V versus RHE . This transition can be clearly observed for Co 3 O 4 /RGO_GO catalysts but it appears only as a shoulder of M II /M III redox transitions for nickel cobaltites.…”

“…The GO precursor was synthesised using the Hummers method from a commercial graphite powder (Sigma–Aldrich) . The RGO precursor was prepared from GO using a previously described method based on the combination of chemical treatments performed with NaOH and NaBH 4 solutions . Co 3 O 4 /RGO_GO, NiCo 2 O 4 /RGO_GO and NiCo 2 O 4 /RGO‐1_RGO catalysts were synthesised using a general procedure .…”

Bifunctional electro-catalytic performances of CoWO4 nanocubes for water redox reactions (OER/ORR)

“…oxides, [12][13][14] hydroxides, 15 phosphates, [16][17][18] suldes, 19,20 mixed metals 21,22 etc.) were considered as the effective water oxidation electrocatalysts.…”

Recent Advances and Prospects of Metal‐Based Catalysts for Oxygen Reduction Reaction

“…In the nonplatinum‐based electrocatalyst, in addition to the M‐N/C catalyst, transition metal oxides (TMOs), chalcogenides, nitrides/oxynitrides, and carbides are included. Although transition metal compound catalysts are difficult to use in acidic media, studies have shown that they exhibit good performance in alkaline media.…”