Fig. 4
Analysis of the nanoquartz. a and b XRD, c FTIR, and d 29Si ssNMR data of the microemulsion-synthesized nanoquartz (black lines) and the products from 1-day (brown lines), 2-day (light green lines), 3-day (light blue lines), 5-day (pink lines), 6-day (purple lines), and 7-day (blue lines) hydrothermal synthesis at 175 °C. b provides a more-detailed view of the 1–7 day hydrothermal XRD data between 2θ = 35–70°, to better show the weaker peaks. The inset in d shows an expanded view of the 7-day 29Si ssNMR spectrum, revealing the small, broad Q3 Si–OH peak at −99 ppm. Q4 Si–O peaks appear at −107 to −118 ppm, Q3 Si–OH peaks at −99 to −101 ppm and Q2 Si(OH)2 peaks at −92 ppm
