Porous NiCo₂O₄ nanostructures as bi-functional electrocatalysts for CH₃OH oxidation reaction and H₂O₂ reduction reaction

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• 作者：Rui Ding ; Li Qi ; Mingjun Jia ; Hongyu Wang
• 关键词：NiCo2O4 ; Electrocatalysts ; CH3OH oxidation reaction ; H2O2 reduction reaction ; Fuel cells
• 刊名：Electrochimica Acta
• 出版年：15 December, 2013
• 年：2013
• 卷：113
• 期：Complete
• 页码：290-301
• 全文大小：3013 K

文摘

Porous nickel cobaltite (NiCo₂O₄) nanostructures were synthesized via a facile chemical deposition route. Their physicochemical properties were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS) and nitrogen sorption measurements. Their electrocatalytic performances were investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) tests. The obtained NiCo₂O₄ materials exhibit typical agglomerate porous nanostructures with the specific surface area (SSA) and pore volume of 190.1 m² g^鈭? and 1.136 cm³ g^鈭?. Remarkably, the NiCo₂O₄ materials exhibit higher electrocatalytic activity, lower overpotential, better stability and greater tolerance compared to those of NiO and Co₃O₄ materials synthesized by the same procedure. As for the NiCo₂O₄ electrode, a current density of 98 mA cm^鈭? was obtained toward CH₃OH electro-oxidation at 0.6 V in 1 M KOH and 0.5 M CH₃OH electrolytes, and a current density of 223 mA cm^鈭? was achieved toward H₂O₂ electro-reduction at 鈭?.3 V in 3 M NaOH and 0.5 M H₂O₂ electrolytes. Moreover, the NiCo₂O₄ electrode shows a desirable stability for both electrocatalytic reactions. The impressive electrocatalytic activity is largely attributable to the binary electroactive sites of Co and Ni species, intrinsic high electronic conductivity and superior porous nanostructures of the NiCo₂O₄ electrode, which are very promising for further development of high performance non-Pt catalysts alkaline fuel cells (AFCs).