Calcination Temperature Effect in Catalyst Reactivity for the CO SELOX Reaction Using Perovskite-like LaBO3 (B: Mn, Fe, Co, Ni) Oxides

H-2 production by conventional processes such as reforming reactions involves formation of some undesired products such as CO. Selective CO oxidation (SELOX) is a good alternative to reduce its concentration because it is a thermodynamically favorable process. Perovskite-like oxides (LaMO3) are used in this work to catalyze the CO-SELOX process and they were synthetized by the self-combustion method. All catalysts were calcined at different temperatures (400 degrees C-800 degrees C) to analyze its impact on the material physicochemical properties. Different analytical techniques were used to study changes in structural and chemical properties. Temperature-programmed reaction (TPRe), using CO oxidation and CO-SELOX, was used to measure the catalytic reactivity of perovskite-like oxides. It was found that catalytic activity decreases when calcination temperature (CT) increases and that is correlated with oxygen mobility, surface defects, and surface concentration of manganese or cobalt species. It is also found that there is a crystalline phase change in the solids when the CT increases from 500 to 600 degrees C. The high catalytic activity observed at low CT remained even if they were calcined below 600 degrees C, which implies the possibility of amorphous species having catalytic activity that do not require a well-structured perovskite.

Automated summary

The study shows that the higher the calcination temperature, the lower the catalytic activity, which is correlated with oxygen mobility, surface defects, and surface concentration of manganese or cobalt species. There is a crystalline phase change in the solids when the calcination temperature increases from 500 to 600 degrees Celsius. High catalytic activity observed at low temperatures remains even if calcined below 600 degrees Celsius, implying the possibility of amorphous species having catalytic activity that do not require a well-structured perovskite.