| 초록 |
We report a facile one-pot solution-phase route to synthesizing a novel composite hierarchical hollow structure without the requirement of catalysts, surfactants, or templates. The as-prepared products consist of discrete WO2 hollow core spheres and W18O49 nanorod shells (urchin-like structures). SEM and TEM studies suggest the following possible growth mechanism: i) amorphous WO2 solid spheres are generated under a thermodynamically controlled growth stage; ii) W18O49 nanorods are deposited on the surface of WO2 solid spheres under a kinetically controlled growth stage; iii) the WO2 core spheres dissolve via inward Ostwald ripening, and the dissolved materials may be recycled into the growing W18O49 nanorods, yielding W18O49/WO2 hollow urchins. We also demonstrate that the morphology of the hollow urchins is readily tunable through the control of the reactant concentrations from nanowires to nanoruchins. The hollow urchins show a very high BET surface area, suggesting that they are ideally suited for chemical sensor or effective catalyst applications. |
