Abstract:

Porous CoFe layered double hydroxide（CoFe LDH） nanosheets electrocatalyst was prepared by low-temperature co-precipitation method.The phase,composition and microstructure of the products were characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,scanning electron microscopy（SEM） and transmission electron microscopy （TEM）.The effect of Fe³⁺ content on the growth behavior of CoFe LDH nanostructures and the electrocatalytic activity on oxy-gen evolution of electrolytic water reaction were discussed.The results showed that the morphology,crystallinity and pore structure of the product can be facilely tuned by the addition of Fe³⁺.Porous CoFe LDH nanosheets with large the total pore volume and enriched active sites were achieved under a suitable Co/Fe ratio.Meanwhile,CoFe LDH resulted in the improvement of the conductivity and the acceleration of charge exchange between Fe and Co active centers,thereby enhancing catalytic activity.For oxygen evolution of electrolytic water reaction,the obtained crystalline Co_0.67Fe_0.33 LDH nanosheets reached a current density of 10 mA/cm² with an overpotential of a 291 mV and a tafel slope of 33 mV/dec,and showed good cycle stability.

Key words: layered double hydroxide, CoFe LDH, low-temperature co-precipitation, electrocatalytic property, oxygen evolution reaction