Thermal Decomposition of Nanostructured Bismuth Subcarbonate

Abstract

Nanostructured (BiO)2CO3 samples were prepared, and their thermal decomposition behaviors were investigated by thermogravimetric analysis under atmospheric conditions. The method of preparation and Ca2+ doping could affect the morphologies of products and quantity of defects, resulting in different thermal decomposition mechanisms. The (BiO)2CO3 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)2CO3 and Ca-(BiO)2CO3 nanowires. The first one was caused by the decomposition of (BiO)4(OH)2CO3 impurities and (BiO)2CO3 with surface defects, with an activation energy of 118–223 kJ/mol, whereas the second one was attributed to the decomposition of (BiO)2CO3 in the core of nanowires, with an activation energy of 230–270 kJ/mol for the core of (BiO)2CO3 nanowires and 210–223 kJ/mol for the core of Ca-(BiO)2CO3 nanowires. Introducing Ca2+ ions into (BiO)2CO3 nanowires improved their thermal stability and accelerated the decomposition of (BiO)2CO3 in the decomposition zone.