The thermal stability of the prepared materials was analysed using a STA F3 449 Jupiter® Netzsch thermal analyser. Simultaneous TG-DTA experiments were performed under a dynamic flow of argon (70 mL/min) with samples without any pretreatment. Each sample of approximately 10 mg was heated from 30°C up to 700 °C at a heating rate of 10 °C/min in an Al2O3 DTA pan. Measurements were repeated twice for each sample.