Details

Autor(en) / Beteiligte

• Loutzenhiser, P. G
• Gálvez, M. E
• Hischier, I
• Stamatiou, A
• Frei, A
• Steinfeld, A

Titel

CO2 Splitting via Two-Step Solar Thermochemical Cycles with Zn/ZnO and FeO/Fe3O4 Redox Reactions II: Kinetic Analysis

Ist Teil von

• Energy & fuels, 2009-05, Vol.23 (5), p.2832-2839

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2009

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Two-step thermochemical cycles for splitting CO2 with Zn/ZnO and FeO/Fe3O4 redox pairs using concentrated solar energy are considered. Thermogravimetric-based kinetic analyses were performed for the reduction of CO2 to CO with Zn and FeO. Both reactions are characterized by an initial fast interface-controlled regime followed by a slow diffusion-controlled regime, which are described using a shell−core kinetic model. In the interface-controlled regime, a power rate law is applied with apparent activation energies 113.7 and 73.4 kJ mol−1, and corresponding reaction orders 0.339 and 0.792, for the Zn/CO2 and FeO/CO2 systems, respectively. In the diffusion-controlled regime, limited by the ion mobility through the oxide shells, the apparent activation energies are 162.3 kJ mol−1 for Zn/CO2 and 106.4 kJ mol−1 for FeO/CO2. Additional reaction mechanisms above the Zn melting point for Zn/CO2 reactions are postulated.