Fig. 4

Oxidation at 375 °C. a Initial HAADF of material at 150 °C in vacuum, b HAADF of region from which b–h were acquired after heating to 375 °C in 330 mbar gas, c Ti K EDX map, d O K EDX map, e S K EDX map, f Summation of nanoprobe diffraction patterns from line across edge of flake, contrast inverted for clarity, g Ti L₃ EELS map, h O pre-K EELS map, i O K EELS map