Thermal Decomposition of Nanostructured Bismuth Subcarbonate

Nanostructured (BiO)(2)CO(3) samples were prepared, and their thermal decomposition behaviors were investigated by thermogravimetric analysis under atmospheric conditions. The method of preparation and Ca(2+) doping could affect the morphologies of products and quantity of defects, resulting in different thermal decomposition mechanisms. The (BiO)(2)CO(3) nanoplates decomposed at 300–500 °C with an activation energy of 160–170 kJ/mol. Two temperature zones existed in the thermal decomposition of (BiO)(2)CO(3) and Ca-(BiO)(2)CO(3) nanowires. The first one was caused by the decomposition of (BiO)(4)(OH)(2)CO(3) impurities and (BiO)(2)CO(3) with surface defects, with an activation energy of 118–223 kJ/mol, whereas the second one was attributed to the decomposition of (BiO)(2)CO(3) in the core of nanowires, with an activation energy of 230–270 kJ/mol for the core of (BiO)(2)CO(3) nanowires and 210–223 kJ/mol for the core of Ca-(BiO)(2)CO(3) nanowires. Introducing Ca(2+) ions into (BiO)(2)CO(3) nanowires improved their thermal stability and accelerated the decomposition of (BiO)(2)CO(3) in the decomposition zone.