Combined experimental and computational modelling studies of the solubility of nickel in strontium titanate
Combined experimental and computational modelling studies of the solubility of nickel in strontium titanate
复制标题
DOI：
10.1039/b902591j
复制
发表时间：
2009-01-01
影响因子：
--
通讯作者：
Fowles, Martin
中科院分区：
文献类型：
--
作者：
Beale, Andrew M.;Paul, Michael;Fowles, Martin
结合X-射线技术和原子计算模型已被用来研究镍在SrTiO 3中的溶解度的关系，这种材料的催化部分氧化甲烷的应用。实验已经证明，低温水热合成成功地制备了在SrTiO 3晶格的八面体配位的Ti 4+位点中掺杂有高达5原子% Ni的单相结晶材料。计算模型表明有限的溶解度，并确定最有利于能量的Ni状态为Ni 2+，而不是Ni 3+。然而，建模也表明，镍应该占据Sr 2+的网站。这个明显的矛盾是解决考虑水热合成过程中的动力学效应。原位EXAFS研究的热行为的Ni掺杂的SrTiO 3在空气和H-2/He表明，NiO相偏析和减少，得到一个高分散的Ni金属颗粒上的SrTiO 3氧化物。
A combination of X-ray techniques and atomistic computational modelling has been used to study the solubility of Ni in SrTiO3 in relation to the application of this material for the catalytic partial oxidation of methane. The experiments have demonstrated that low temperature, hydrothermal synthesis is successful in preparing monophase, crystalline material with up to 5 atom % Ni doped in the octahedrally coordinated Ti4+ site of the SrTiO3 lattice. Computational modelling indicates limited solubility and identifies the most energy favoured Ni state as Ni2+ as opposed to Ni3+. However, modelling also suggests that thermodynamically Ni should occupy the Sr2+ site. This apparent contradiction is resolved by considering the kinetic effects operating during hydrothermal synthesis. An in situ EXAFS study of the thermal behaviour of Ni doped SrTiO3 in air and H-2/He shows that NiO phase segregates and reduces to give a high dispersion of Ni metal particles on the SrTiO3 oxide.