报告时间：7月28日，星期五，10:30-11:30 

报告地点：能源楼会议中心一号会议室 

报告人：Prof. Stjepko Krehula, Ru？er Bo？kovi？ Institute, Zagreb, Croatia 

　　报告摘要

　　Mixed Ni-Fe(oxy)hydroxides of various Ni:Fe molar ratios (from 0:100 to 100:0) were synthesized by a hydrothermal precipitation in a highly alkaline medium and investigated using X-ray powder diffraction (XRPD), M？ssbauer spectroscopy, magnetic measurements, thermogravimetric analysis (TGA), scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR) spectroscopy and ultraviolet–visible–near infrared (UV-Vis-NIR) spectroscopy. Fe oxyhydroxide goethite (α-FeOOH) nanorods and Ni hydroxide β-Ni(OH)₂ fluffy nanostructures were formed in a pure Fe or Ni system, respectively. Ni-doped α-FeOOH or Fe-doped β-Ni(OH)₂ were formed at intermediate Ni:Fe ratios accompanied with Ni-ferrihydrite and Ni ferrite as minor phases. Incorporation of Ni in α-FeOOH and Fe in β-Ni(OH)₂ by a cation substitution was confirmed from the shifts in the position of XRPD lines (due to a difference in ionic radius of  Fe³⁺ and Ni²⁺) and from a decrease in the hyperfine magnetic field in α-FeOOH (due to a substitution of Fe³⁺ by Ni²⁺ with a lower magnetic moment). The Fe³⁺-for-Ni²⁺ substitution in β-Ni(OH)₂ caused a formation of an interstratified structure with β-Ni(OH)₂ and α-Ni(OH)₂ structural units interconnected inside the same structural layers and in the same crystallites. An increased Fe content in Ni hydroxide caused an increase in amount in α-Ni(OH)₂ structural units containing intercalated water molecules and nitrate ions. Mossbauer spectra showed the presence of some Fe³⁺ ions located in the highly distorted octahedral sites, presumably at the boundary between α-Ni(OH)₂ and β-Ni(OH)₂ structural units. Electrochemical measurements showed significantly higher oxygen evolution reaction (OER) activities of Ni-doped goethite and Fe-doped Ni hydroxide compared to pure phases. The highest activity (the lowest overpotential) was measured for sample Ni67 (67 mol% Ni, 33 mol% Fe) containing Fe-doped Ni hydroxide and Ni ferrite as a minor phase.