Thermal stability study of catalyst (CuO/ZnO) supported on phenyl polyhedral oligomeric silsesquioxanes

The stability of heterogeneous catalytic systems is critical for their long-term. Therefore, the thermal degradation behaviors of CuO/ZnO supported on octaphenyl and dodecaphenyl polyhedral oligomeric silsesquioxane and silsesquioxane were investigated. The presence of the metal oxides does not interfere with the degradation mechanisms up to the temperature of 450 °C. After that temperature, the metal oxides accelerate the degradation rate of the supports. Irreversible thermal events, including molecular relaxation and crystal rearrangement, with low transition energy, were observed using differential scanning calorimetry. In all cases, the thermal analysis revealed complex behaviors. The crystal structure of both supports is destroyed in the oxidative atmosphere at 900 °C but partially destroyed in the nitrogen atmosphere. The vibrational frequencies of the residues in the inert and oxidative atmosphere showed after 500 °C the deformation of the Si–O peak due to intercage linkages formation.