Surfactant-Free Solvothermal Method for Synthesis of Mesoporous Nanocrystalline TiO₂ Microspheres with Tailored Pore Size

Figure 2

SEM images of mesoporous TiO₂ microspheres prepared with different amounts of urea: (a) 8 mmol; (b) 12 mmol; (c) 16 mmol; (d) 20 mmol.

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