School of Chemistry, EaSTChem, University of St Andrews, St Andrews, Fife KY16 9ST, UK.
Dalton Trans. 2013 Jun 14;42(22):7880-7. doi: 10.1039/c3dt32064b. Epub 2013 May 3.
Sr(1-x)NbO3 is an unusual material that displays both metallic type conduction and photocatalytic activity, despite being an NbIV oxide, and it sustains photo-oxidation without degradation. The influence of crystal structure, surface area and surface chemistry on the photocatalytic activity of strontium niobate has been investigated. The crystal structure of strontium niobate depends on the Sr content of the A site, with cubic symmetry for Sr ≤ 0.92 and orthorhombic symmetry for 0.92 < Sr ≤ 0.97. The change of crystal structure from cubic to orthorhombic symmetry seems to have a negative effect on the photocatalytic activity, as the NbO6 octahedra become distorted and unfavourable for d-orbital overlapping. The photocatalytic activity increased significantly by enlarging the surface area through ball milling, nevertheless, a clear trend for the surface area effect on activity is not obtained among samples with different Sr content. An enrichment of Sr on the surface of strontium niobate was observed by XPS, which seems to be a governing factor for improving stability.
Sr(1-x)NbO3 是一种不寻常的材料，尽管它是 NbIV 氧化物，但它具有金属型导电性和光催化活性，并能在不降解的情况下维持光氧化。已经研究了晶体结构、比表面积和表面化学对铌酸锶光催化活性的影响。铌酸锶的晶体结构取决于 A 位的 Sr 含量，Sr ≤ 0.92 时为立方对称，0.92 < Sr ≤ 0.97 时为正交对称。晶体结构从立方对称向正交对称的转变似乎对光催化活性有负面影响，因为 NbO6 八面体变得扭曲，不利于 d 轨道重叠。通过球磨来增大比表面积可显著提高光催化活性，然而，在具有不同 Sr 含量的样品中，并未获得比表面积对活性的明显影响趋势。XPS 观察到 Sr 在铌酸锶表面富集，这似乎是提高稳定性的控制因素。
