Effect of calcination temperature on the structural characteristics and catalytic activity for propene combustion of sol–gel derived lanthanum chromite perovskite

The perovskite type lanthanum chromite LaCrO3 has been synthesized by a sol–gel method. Its bulk structural and surface characteristics have been examined by X-ray diffraction (XRD), SEM, SBET measurements, Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) as a function of the calcination treatment performed between 200 and 1000 °C over the precursor powder and in correlation with information achieved from TG-DTA thermal analysis. The characterization results are employed to rationalize the catalytic behaviour of the system towards propene complete oxidation. It is shown that the catalytic activity becomes optimized when a single perovskite LaCrO3 phase is achieved upon calcination at T > ca. 700 °C. In contrast, coexistence of perovskite LaCrO3 and monazite LaCrO4 at lower calcination temperatures appears detrimental to the combustion activity of the system.

A study of a sol–gel prepared lanthanum chromite perovskite catalyst following in detail the structural evolution as a function of the calcination steps between 200 and 1000 °C in correlation with the catalytic activity for propene combustion of the system at selected temperatures in such range is presented. Figure optionsDownload as PowerPoint slide