Portugal Guilherme Ribeiro, Arantes Jeverson Teodoro
Federal University of ABC (UFABC), Center for Engineering, Modeling and Applied Social Science - CECS, Santo André, São Paulo, Brazil.
Phys Chem Chem Phys. 2020 Apr 14;22(14):7250-7258. doi: 10.1039/c9cp06769h. Epub 2020 Mar 24.
Sodium tantalate nanostructures have been classified among the best materials to conduct photocatalytic reactions. Therefore, understanding the relationship between nanoscale surface phenomena and photocatalytic properties is of fundamental importance. We performed Density Functional Theory calculations to investigate how chemically different facets may affect intrinsic properties of NaTaO cubic nanowires. Besides half-metallicity, the NaO-terminated wire relaxes structurally, presenting unoccupied down O 2p levels located above its valence band due to severely reduced coordination of its edges, which may allow it to be applied in spintronics systems. NaTaO-terminated wires have surface TaO units that, upon structural reconstruction, become more planar and introduce occupied Ta 5d levels below their conduction band. The emergence of such levels is also related to the overlap of Ta d orbitals from adjacent NaTaO facets. Amongst other properties discussed herein, localized levels may be relevant for photocatalysis not only in terms of intrinsic bandgap engineering but also concerning the alignment with water redox potentials.
钽酸钠纳米结构已被归类为进行光催化反应的最佳材料之一。因此，了解纳米尺度表面现象与光催化性能之间的关系至关重要。我们进行了密度泛函理论计算，以研究化学性质不同的晶面如何影响NaTaO立方纳米线的本征性质。除了半金属性外，以NaO为端基的纳米线在结构上会弛豫，由于其边缘的配位严重减少，在其价带上方呈现未占据的向下O 2p能级，这可能使其适用于自旋电子学系统。以NaTaO为端基的纳米线具有表面TaO单元，在结构重构后，这些单元变得更加平面，并在其导带下方引入占据的Ta 5d能级。这些能级的出现还与相邻NaTaO晶面的Ta d轨道重叠有关。在本文讨论的其他性质中，局域能级不仅在本征带隙工程方面，而且在与水氧化还原电位的对齐方面，可能与光催化相关。
