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Hybrids of Fe3O4/CoSe2 as efficient electrocatalysts for oxygen reduction reaction

Huang, Yanli, Feng, Chuanqi, Wu, Huimin, Wang, Shengfu, Wang, Feng, Liu, Huakun
Journal of materials science 2018 v.53 no.2 pp. 1123-1134
X-ray diffraction, X-ray photoelectron spectroscopy, catalysts, dielectric spectroscopy, electrochemistry, ethanol, ethylene glycol, hot water treatment, iron oxides, methanol, oxygen, scanning electron microscopy, sulfuric acid, transmission electron microscopy
Here we demonstrated two different hydrothermal methods for synthesizing Fe₃O₄/CoSe₂ hybrids with different weight ratios of Fe₃O₄ and CoSe₂. The synthesized materials were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. And the electrochemical properties were obtained by linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy. For the first method, the obtained catalyst with loading 20% Fe₃O₄ on CoSe₂ (C20a) exhibits the highest oxygen reduction reaction activity. While for the second method, the obtained catalyst with loading 30% Fe₃O₄ on CoSe₂ (C30b) exhibits the highest oxygen reduction reaction activity, with an onset potential of 0.775 V, a half-wave potential of 0.600 V, and Tafel slope of 65 mV decade⁻¹ in O₂-saturated 0.5 M H₂SO₄. Which are better than those of C20a (0.753, 0.567 V and 67 mV decade⁻¹), CoSe₂ (0.708, 0.560 V and 66 mV decade⁻¹) and Fe₃O₄ (0.700, 0.556 V and 79 mV decade⁻¹). More importantly, C30b shows much higher stability and better methanol, ethanol and ethylene glycol tolerance than other prepared materials.