论文标题
偶然的钼缺陷复合物
Molybdenum Defect Complexes in Bismuth Vanadate
论文作者
论文摘要
MonoClinic Bismuth Vanadate（Bivo $ _4 $）是一种有前途的$ n $ type半导体，用于在阳光驱动的水分中应用。几项研究表明，高浓度的MO和W掺杂剂可大大增强其光催化活性。在目前的工作中，我们执行了\ textit {ab initio}计算，以评估bivo $ _4 $中MO相关对之间最有利的相对位置。令人惊讶的是，我们验证了Mo $ $ _ {\ text {v}} $ bivo $ _4 $中的最低能量配置，尽管在最近的静脉排斥和较大的晶体晶格上发生了较大的静电率和较大的应变。对于W $ _ {\ text {v}} $缺陷对中的W $ _ {\ doped bivo $ _4 $中的缺陷对观察到了类似的结果。我们表明，这种效果的起源在于杂质的原子轨道之间的有利杂交，这种杂交只有在它们彼此最接近时才能得到验证，从而导致焓增强，从而克服了对构造能量的排斥成分。结果，MO和/或W掺杂的Bivo $ _4 $可能会呈现供体 - 供体缺陷复合物，这是可以在改善这些金属氧化物的光催化活性的实验方法中应用的结果。
Monoclinic bismuth vanadate (BiVO$_4$) is a promising $n$-type semiconductor for applications in sunlight-driven water splitting. Several studies have shown that its photocatalytic activity is greatly enhanced by high concentrations of Mo and W dopants. In the present work, we performed \textit{ab initio} calculations to assess the most favorable relative position between Mo-related pairs in BiVO$_4$. Surprisingly, we verify that the lowest energy configuration for Mo$_{\text{V}}$ pairwise defects in BiVO$_4$ occurs on nearest-neighbor sites, despite the higher electrostatic repulsion and larger strain on the crystal lattice. Similar results were observed for W$_{\text{V}}$ defect pairs in W-doped BiVO$_4$. We show that the origin of this effect lies in a favorable hybridization between the atomic orbitals of the impurities that is only verified when they are closest to each other, resulting in an enthalpy gain that overcomes the repulsive components of the pair formation energy. As a consequence, Mo and/or W doped BiVO$_4$ are likely to present donor-donor defect complexes, which is an outcome that can be applied in experimental approaches for improving the photocatalytic activity of these metal oxides.
