Figure 2 | Characterization of nano-SiO2 derived from RHs. a–c, SEM images of SiO2 obtained by heating raw or leached RHs at different temperature.
d,e, TGA (d) and DTA (e) profiles of raw and leached RHs measured under flow of simulated air (20% O2 in Ar) with a ramp rate of 5uC min21.
f, Statistical analysis of particle sizes of nano-SiO2 shown in (c) and nano-Si (Si-RH-5) reduced from it.