No impurity phases were found in the XRD patterns of TiO2 NP samples. The diffraction peaks were indexed with powder diffraction standard data (ICDD 21-1272). The crystallite
size of TiO2 NPs is estimated from broadening of anatase (101) peak using the Debye-Scherrer formula [14]. The calculated crystallite size for TiO2 PS-341 in vivo nanoparticles prepared at 170°C is 6.89 nm. The nanoparticles were also prepared at lower temperatures (140°C, 150°C, and 160°C) and higher temperatures (180°C and 190°C). NPs prepared at lower temperatures have smaller crystallite size but the product yield is low, while NPs prepared at higher temperatures have higher yield but the crystallite size is bigger. The optimum temperature is 170°C for the preparation of TiO2 NPs with narrow size distribution and nearly 100% yield. Figure 1 The Rietveld profile fitting of X-ray diffraction pattern of pure anatase TiO 2 NPs. Experimental (symbols) and fitting (solid lines) X-ray diffraction patterns. The positions
of Bragg reflections are denoted by vertical bars. The difference (experiment minus calculation) curve is shown by a solid line at the bottom. The morphology of SA-coated and DMSA-coated TiO2 NPs was examined by TEM measurements. As shown in Figure 2a,b, the resulting TiO2 NPs (SA-coated and DMSA-coated) appear as spherical particles with good monodispersity. The size distribution of the nanoparticles is in Additional file 1: Figure S2, calculated Selleckchem SCH772984 by measuring hundred particles, shows that the TiO2 NPs have an average size of 6 nm, which is in good accordance with the size of TiO2 NPs observed through XRD measurement. The inset of Figure 2a,b 3-oxoacyl-(acyl-carrier-protein) reductase presents the SAED pattern of TiO2 NPs, confirming that anatase crystal structure can be indexed with (101), (103), (200), (105), (213), (116), (107), and (008) crystallographic planes. Figure 2 TEM image of the TiO 2
NPs. (a) Toluene-dispersible SA-coated NPs. (b) Water-dispersible DMSA-coated NPs. The insets show the corresponding electron diffraction patterns. UV-vis absorption spectra of TiO2 nanoparticles dispersed in toluene and DI water are measured and shown in Figure 3. The absorption coefficient (α) was determined from the optical spectrum using the formula where A and t are the measured absorbance and thickness of the sample, respectively. The optical bandgap energy (E g) was evaluated from the absorption spectrum, and the optical absorption coefficient (α) near the absorption edge is given by following equation: where h, ν, B, and E g are Plank’s constant, frequency of incident photons, constant, and optical bandgap energy, respectively. E g was estimated by plotting hν versus (αhν)1/2 and extrapolating linear portion near the onset of absorption edge to the energy axis as shown in the inset of Figure 3. The determined value of E g is 3.06 and 3.1 eV for TiO2 nanoparticles dispersed in toluene and DI water, respectively.