Synthesis of Porous Se@SiO2 Nanospheres

Porous Se@SiO₂ nanospheres (College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai, China) used herein were synthesized as described in our previous study.21 (link),23 (link) Firstly, Cu_2−xSe nanocrystals were prepared and mixed with n-hexanol, n-hexane, deionized water, Triton X-100, and tetraethyl orthosilicate. [Cu(NH₃)₄]²⁺ was developed by adding ammonium hydroxide to the mixture. Oxygen was used to oxidize Se²⁻ to develop Se quantum dots. In an alkaline environment, the silica was coated upon the Se quantum dots by orthosilicate hydrolysis, thus forming solid Se@SiO₂ nanospheres. Then, the solid Se@SiO₂ nanospheres were coated with polyvinylpyrrolidone. After treatment with hot water, the Se@SiO₂ nanospheres formed porous structures. Porous Se@SiO₂ nanospheres were characterized by means of a D/max-2550 PC X-ray diffractometer (XRD; Rigaku Corporation, Tokyo, Japan; Cu-Kα radiation) and transmission electron microscopy (TEM; JEM-2100F; JEOL, Tokyo, Japan). Synthesized porous Se@SiO₂ nanospheres were then dispersed in deionized water for subsequent experiments.