Conversion of Sb2Te3 hexagonal nanoplates into three-dimensional porous single-crystal-like network-structured Te plates using oxygen and tartaric acid.

Novel applications of nanostructures in catalysis, electronics, photonics, and bionanotechnology are driving the exploration of synthetic approaches to control and manipulate their chemical composition, structure, and morphology. As well as the design of synthetic strategies to produce a new class of nanoscale materials, recent developments have enabled the chemical transformation of one crystalline material into another desired target material. Three of the most important methods for chemical transformation are the ionexchange reaction, the Kikendall effect, and stabilizerdepleted binary semiconductor nanocrystals. The first two methods have been shown to produce nanomaterials with a diverse structure and a controlled composition, but are not suitable to transform binary materials into unary semiconductors. Interestingly, the third method has been successfully adopted by Kotov and Tang et al. to convert CdE (E=Se, Te) into unary E solid nanowires and angled Te nanocrystals. Among the various materials, porous nanostructures have received increasing attention owing to their improved chemical and physical performance over solid materials, as well as their intriguing applications in a variety of fields. In comparison with their polycrystalline counterparts, singlecrystal-like materials have been found to reduce the number of defects, and have enhanced electron-transfer and catalytic properties. However, the development of a facile technique to transform binary materials into three-dimensional (3D) porous unary semiconductors, especially with single-crystallike structures, remains a great challenge. Herein we report a facile approach to transform the asprepared Sb2Te3 nanoplates into 3D porous Te plates through the dissolution of Sb ions, the oxidation of Te ions to Te, and a subsequent Ostwald ripening process induced by oxygen and tartaric acid (TA). We have demonstrated that this method can be adopted to convert Sb2Te3 nanoplates into porous heterogeneous In/Te networks through the reduction of InCl3 during the chemical transformation of Sb2Te3. Furthermore, the as-prepared porous Te plates can be used as the template for the highly efficient synthesis of 3D porous network-structured noble-metal nanoplates with promising applications. Firstly, the Sb2Te3 hexagonal nanoplates were synthesized by using the reported solution–chemical method. Figure 1a shows a scanning electron microscopy (SEM) image of hexagonal nanoplates with a thickness of 50–200 nm. The typical powder X-ray diffraction (XRD) pattern displayed in Figure 1 f identifies these hexagonal plates as the rhombohe-