Facile Synthesis, Growth Mechanism, and UV-Vis Spectroscopy of Novel Urchin-like TiO2/TiB2 Heterostructures

A TiO2/TiB2 heterostructure with a sea-urchin shape, as a new material system, was successfully synthesized by a facile hydrothermal approach in an aqueous solution of ethylenediamine (EDA). This complex architecture is a core/shell urchin structure composed of high-density anatase TiO2 (A-TiO2) nanorod-built networks (shell part) that stand on a TiB2 microcrystal (core part). The microstructure can be controlled by the temperature, time, reactants, and additives. A three-step sequential oriented attachment growth model is proposed based on the observations from a time-dependent and temperature-dependent morphology evolution process. Importantly, UV-vis absorption spectra show that the absorption peak and absorption edge has all obvious shift to a lower energy because of the nanometric effect and N-doping.