SO3 decomposition over CuO-CeO2 based catalysts in the sulfur-iodine cycle for hydrogen production

The effect of several catalyst supports with large specific surface area (such as SiC, Al2O3, SiC-Al2O3-ball, and SiC-Al2O3) on catalytic activity was evaluated in this study. CuO-CeO2 supported on SiC-Al2O3 exhibited high stability and activity, which was considerably close to the thermodynamic equilibrium curve at 625 °C during the stability test for 50 h. The SO3 decomposition temperature decreased from 750 °C to 625 °C. SiC-Al2O3contained numerous micropores and mesopores and had a large specific area, indicating strong adsorption, as determined by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and nitrogen adsorption measurement. X-ray photoelectron spectroscopy (XPS) revealed that the surface of SiC-Al2O3consisted of Al2O3, SiC, and SiO2 and that the cerium oxide surface had the largest number of defects. Temperature-programmed reduction (H2-TPR) results indicated that the cerium-copper oxides on the surface of powdered SiC-Al2O3 had the strongest redox potential and that CuO had the lowest reduction temperature.