Characterization and Catalytic Properties of Ni‐Fe Spinel Catalysts for Total Oxidation of Ethanol

다국어 초록 (Multilingual Abstract)

This paper deals with the study of the reducibility of Ni−Fe spinel oxides prepared by co‐precipitation and hydrothermal methods with NaOH or ammonia and their behavior in ethanol combustion. The reducibility was investigated by X‐ray photoelectron spectroscopy (XPS) after pretreatment under H2 at 400 °C. Depending on the synthesis method, structural properties (X‐ray powder diffraction (XRD) and Raman analysis), the surface area (BET), particle size (Rietveld refinement), as well as the surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied. The best performances were obtained for hydrothermal conditions with a total conversion achieved at ∼ 300 °C. Ni2+ species seem to play a significant role in complete oxidation of ethanol; they were identified as the active species. A good correlation between structural, textural, reducibility and catalytic activity was established.
The catalytic activity in ethanol oxidation may not only be related to the structural and textural characteristic of the sample but also to its surface composition. Ni2+ species seem to play a significant role in complete oxidation of ethanol; they were identified as the active species. The oxidation of ethanol is favored over basic surfaces, as ethanol is an acidic molecule and may then interact more easily with a basic surface.