Efficient oxygen reduction reaction using mesoporous Ni-doped Co₃O₄ nanowire array electrocatalysts

Abstract

Catalyst for oxygen reduction reaction (ORR) is of highly industrial importance for fuel cells and metal-air battery. ORR catalysts with high electrochemical activity, selectivity, stability and low cost are extremely desirable but still remain challenging. Herein, mesoporous Ni-doped Co 3 O 4 nanowire (NW) arrays are reported as a highly efficient and low-cost ORR catalyst. The Ni doping affords more electroactive sites and enhanced conductivity, and the mesoporous structure provides increased surface exposure, which may improve ion/electron transport and reduce charge transfer resistance. The NW arrays exhibit a high ORR activity with four-electron transfer reaction in alkaline media, a half-wave potential of 0.86 V vs. RHE and a superior stability to the commercial Pt (20 wt. %)/C catalyst. Our results suggest that the mesoporous Ni-doped Co 3 O 4 NW arrays could be a promising ORR catalyst for fuel cells and metal-air batteries.

Co3O4 Nanoparticles Anchored on Selectively Oxidized Graphene Flakes as Bifunctional Electrocatalysts for Oxygen Reactions

“…Deconvoluted Co 2p high resolution spectra of pure Co 3 O 4 and Co 3 O 4 @GF_ox are presented in Figure (left); binding energy, BE, values and relative atomic percentages determined based on the deconvolution of high resolution spectra are summarized in Table S1. The Co 2p high resolution spectra present two main peaks corresponding to Co 2p 3/2 and Co 2p 1/2 spin‐orbit components ,,. The energy difference Δ2p 3/2 ‐2p 1/2 of 15.2 – 15.3 eV is in well agreement with the reported typical values of 15.1 – 15.25 eV for the mixed‐valence cobalt oxide Co 3 O 4 , corroborating the XRD data .…”

Defect‐Rich Nitrogen Doped Co3O4/C Porous Nanocubes Enable High‐Efficiency Bifunctional Oxygen Electrocatalysis

“…75‐2078) . More remarkably, the diffraction peaks of N‐doped samples shift negatively as the nitridation temperature increased, and there is no obvious phase change until the nitridation temperature reached 400 °C (Figure S1, Supporting Information), implying the more substitution of O by N atoms in the N‐doped Co 3 O 4 samples . For N‐Co 3 O 4 @NC‐4, the occurrence of cobalt nitride impurity phases is distinct .…”

Hierarchical NiCo2S4 Nanowire Arrays Supported on Ni Foam: An Efficient and Durable Bifunctional Electrocatalyst for Oxygen and Hydrogen Evolution Reactions

“…All of the potentials in the LSV polarization curves were iR‐corrected with respect to the ohmic resistance of the solution, unless specifically indicated. Because the Ni foam might have dissolved during hydrothermal synthesis, due to decomposition of urea in the aqueous environment, accurate measurement of the catalyst loading on the Ni foam was challenging. Therefore, the reported current density was based on the geometrical area.…”