Pure hematite nanorods and very long and thin cobalt-doped hematite nanorods (nanoneedles) were prepared by a combined precipitation and annealing method. The influence of the level of cobalt doping on different properties of hematite nanorods was investigated. Incorporation of cobalt in the form of low-spin Co³⁺ ions into the structure of hematite by substitution for high-spin Fe³⁺ ions was proved by determination of a significant unit cell contraction by powder X-ray diffraction (PXRD) and characteristic positions of the absorption edge in X-ray absorption near edge structure (XANES) spectra and peaks in X-ray emission (XES) spectra. Cobalt doping caused a gradual elongation and thinning of hematite nanorods – very long and thin 1D nanoparticles (nanoneedles) were formed in the presence of 10 and 12 mol% Co. Magnetic measurements showed a strong increase in low-temperature remanent magnetization and coercivity upon cobalt doping, as well as a disappearance of the Morin transition, which was also confirmed by Mössbauer spectroscopy. Cobalt doping significantly affected optical properties of hematite nanorods – absorption in the visible and NIR ranges increased, which was accompanied by narrowing of the optical band gap. Compared with pure hematite nanorods cobalt-doped hematite nanoneedles showed a significantly better electrocatalytic activity for the oxygen evolution reaction (OER).

通过沉淀和退火相结合的方法制备了纯赤铁矿纳米棒和非常长且很薄的掺钴赤铁矿纳米棒（纳米酮）。研究了钴掺杂水平对赤铁矿纳米棒不同性能的影响。通过取代高自旋Fe ³⁺将低自旋Co ³⁺离子形式的钴掺入赤铁矿结构中通过粉末X射线衍射（PXRD）和X射线吸收近边缘结构（XANES）光谱中的吸收边缘的特征位置以及X射线发射（XES）光谱中的峰确定了显着的晶胞收缩来证明离子。钴掺杂导致赤铁矿纳米棒逐渐伸长和变薄–在10和12 mol％Co的存在下形成了非常长且很薄的1D纳米颗粒（纳米针）。磁性测量表明，钴的低温剩余磁化强度和矫顽力大大增加掺杂，以及莫林跃迁的消失，这也得到了莫斯鲍尔光谱学的证实。钴掺杂显着影响赤铁矿纳米棒的光学性能-可见光和NIR范围内的吸收增加，这伴随着光学带隙的缩小。