Surface properties and performance for VOCs combustion of LaFe{sub 1-y}Ni{sub y}O{sub 3} perovskite oxides

LaFeO{sub 3}, LaNiO{sub 3} and substituted LaFe{sub 1-y}Ni{sub y}O{sub 3} (y=0.1, 0.2 and 0.3) perovskites were synthesized by the citrate method and used in the catalytic combustion of ethanol and acetyl acetate. Chemical composition was determined by atomic absorption spectrometry (AAS) and specific areas from nitrogen adsorption isotherms. Structural details and surface properties were evaluated by temperature-programmed reduction (TPR), infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), temperature-programmed desorption of oxygen (O{sub 2}-TPD) and photoelectron spectroscopy (XPS). Characterization data revealed that total insertion of nickel in the LaFeO{sub 3} takes place for substitution y=0.1. However, NiO segregation occurs to some extent, specifically at higher substitutions (y>0.1). The catalytic performance of these perovskites was evaluated in the combustion of acetyl acetate and ethanol. Among these molecules, ethanol exhibited the lowest ignition temperature, and the catalytic activity expressed as intrinsic activity (mol m{sup -2} h{sup -1}) was found to increase substantially with the nickel substitution. These results can be explained in terms of the cooperative effect of a LaFe{sub 1-y}Ni{sub y}O{sub 3} and NiO phases, whose relative concentration determines the oxygen activation capability and hence their reactivity. - Graphical abstract: LaFeO{sub 3}, LaNiO{sub 3} and substituted LaFe{sub 1-y}Ni{sub y}O{sub 3} (y=0.1, 0.2 and 0.3) perovskite-type oxides have been investigated as catalysts in the total combustion of ethanol and acetylacetate. The characterization indicate variation in specific surface area, crystal structure, reducibility and surface composition. The catalytic activity expressed as intrinsic activity (mol m{sup -2} h{sup -1}) increases with nickel substitution. A synergy between Ni{sup 3+} and Fe{sup 3+} cations at the B position of the LaFe{sub 1-y}Ni{sub y}O{sub 3} perovskite for VOCs combustion was observed.