Sn-doped hematite (α-Fe₂O₃) nanoparticles of fairly uniform and Sn-dependent size and shape were synthesized via a simple combination of hydrothermal co-precipitation and calcination. The effects of Sn doping on the unit cell size, crystallinity, particle size and shape, as well as the magnetic, optical and photocatalytic properties of hematite nanoparticles were analyzed. The incorporation of Sn⁴⁺ ions into the crystal structure of hematite was confirmed by determination of the unit cell expansion due to the replacement of octahedrally coordinated Fe³⁺ ions by significantly larger Sn⁴⁺ ions, as well as a substantially reduced hyperfine magnetic field due to magnetic dilution upon the substitution of non-magnetic Sn⁴⁺ ions for magnetic high-spin Fe³⁺ ions. Sn doping caused a decrease in length and width and an increase in thickness of elongated hematite nanoparticles. Fairly uniform Sn-doped hematite nanoellipsoids or nanocuboids were formed, depending on the Sn content. Temperature dependence of magnetization measurements showed the disappearance of the magnetic phase transition (Morin transition) in hematite upon Sn doping. Magnetic coercivity decreased upon Sn doping due to a decrease in shape anisotropy induced by the change in particle shape from nanorods to nanoellipsoids and nanocuboids. The optical and electronic properties of hematite nanoparticles were significantly affected by Sn doping – the absorption edge was shifted to higher wavelengths, while direct and indirect optical band gaps narrowed with the increasing Sn⁴⁺-for-Fe³⁺ substitution. Sn-doped hematite nanoellipsoids containing 4.3 mol% Sn exhibited a substantial visible light photocatalytic activity in the heterogeneous photo-Fenton process, but this activity significantly decreased with higher Sn doping.

Sn掺杂的赤铁矿（α-Fe ₂ O ₃）纳米颗粒具有相当均匀且与Sn相关的尺寸和形状，通过水热共沉淀和煅烧的简单组合合成。分析了Sn掺杂对赤铁矿纳米颗粒的晶胞尺寸、结晶度、粒径和形状以及磁性、光学和光催化性能的影响。由于八面体配位的 Fe ³⁺离子被明显更大的 Sn ⁴⁺取代，因此通过测定晶胞膨胀来确认Sn ⁴⁺离子掺入到赤铁矿的晶体结构中离子，以及由于用非磁性 Sn ⁴⁺离子替代磁性高自旋 Fe ³⁺后的磁性稀释而显着降低的超精细磁场离子。Sn掺杂导致伸长的赤铁矿纳米颗粒的长度和宽度减小以及厚度增加。根据 Sn 含量，形成了相当均匀的 Sn 掺杂赤铁矿纳米椭球或纳米长方体。磁化测量的温度依赖性表明，Sn掺杂后赤铁矿中的磁相变（莫林转变）消失。由于从纳米棒到纳米椭圆体和纳米长方体的颗粒形状变化引起的形状各向异性降低，因此在 Sn 掺杂时矫顽力降低。Sn掺杂显着影响了赤铁矿纳米粒子的光学和电子特性——吸收边缘向更高波长移动，而直接和间接光学带隙随着Sn ⁴⁺ -for-Fe ³⁺的增加而变窄代换。含 4.3 mol% Sn 的 Sn 掺杂赤铁矿纳米椭球体在非均相光芬顿过程中表现出显着的可见光光催化活性，但这种活性随着 Sn 掺杂量的增加而显着降低。