Synthesis mechanism of heterovalent Sn2O3 nanosheets in oxidation annealing process |
(a) TG curve, (b) adsorbed oxygen content from XPS verus sample weight, (c) XRD, (d) XPS patterns, and (d) valence-band XPS spectra of Sn3O4 annealed at various temperatures at a 5 °C/min ramp rate. |