Fig. 2

Morphology and surface area characterizations of pristine DF, DF-SiO, and DF-Si, respectively. a–c SEM images of pristine DF (a scale bar = 5 μm), DF-SiO (b scale bar = 5 μm), and DF-Si (c scale bar = 5 μm), respectively. d–f TEM images of pristine DF (d scale bar = 1 μm), DF-SiO (e scale bar = 500 nm), and DF-Si (f scale bar = 500 nm), respectively. g–i N2 adsorption/desorption curves of pristine DF (g), DF-SiO (h), and DF-Si (i), respectively. j–l SXT images of DF (j scale bar = 2 μm), DF-SiO (k scale bar = 2 μm), and DF-Si (l scale bar = 2 μm), respectively