The thermal stability of the different samples was evaluated by thermogravimetric analyses (TGA) using a Mettler Toledo Thermogravimetric Analyzer (TGA/SDTA 85-F). 10 g of tested sample was used for each measurement. All the measurements were performed under nitrogen atmosphere, with a gas flow of 10 mL min−1 by heating the material from room temperature to 900 ◦C at a heating rate of 10 ◦C min−1. The analysis was performed by duplicate.