Successive reduction-oxidation activity of FeOx/TiO2 for dehydrogenation of ethane and subsequent CO2 activation

Prototype FeOx/TiO2 was applied for dehydrogenation of ethane to ethylene and successive CO2 activation to CO for further chemical looping (CL) application. The Fe(5)/TiO2 exhibited a facile redox cyclic activity with an insignificant coke formation and comparable CO2 activation through reduction-oxidation reaction cycles. During the oxidative dehydrogenation of chemical looping (CL-ODH), the Fe nanoparticles (Fe2O3) on the rutile TiO2 were partially transformed to the thermally stable FeTiO3 phases with its lower oxidation state (Fe2+) below 700 degrees C. However, the formations of Fe2TiO5 phases were found to be less active than the smaller sizes of iron oxides (Fe3+). The thermally stable iron phases with their reversible redox natures between FeTiO3 and Fe2O3 phases were responsible for a stable reduction-oxidation activity. The robust preservation of the partially reduced surface Fe2+ sites with the copresence of the larger Fe2O3 hematite crystallites on the TiO2 was responsible for improving the redox activity and stability.