Preparation, structure and catalytic properties of magnetically separable Cu–Fe catalysts for glycerol hydrogenolysis

Abstract

The Cu–Fe catalysts with stoichiometric proportion (Cu/Fe molar ratio was 0.5) were prepared by an epoxide assisted route. The structural properties of Cu–Fe catalysts were determined by X-ray diffraction (XRD), and Mössbauer spectroscopy measurements. These results indicated that a crystalline phase transformation from c-CuFe₂O₄ to t-CuFe₂O₄ occurred when elevating the calcination temperature from 500 to 600 °C. The M–H plots exhibited that all Cu–Fe catalysts had ferromagnetic nature and the saturation magnetization values monotonously increased with increasing calcination temperature irrespective of the phases composition. The significant superparamagnetic behavior was observed in the results of magnetic and Mössbauer spectroscopy measurements. The H₂ temperature-programmed reduction (H₂-TPR) was also conducted for examining the reducibility of Cu–Fe catalysts. The catalytic performance of Cu–Fe catalysts was examined for the hydrogenolysis reaction of glycerol. It is found that the formation of spinel CuFe₂O₄ greatly enhances the hydrogenolysis activity. The highest glycerol conversion (47%) was obtained over CuFe-500 catalyst, while the selectivity of 1,2-propanediol was maintained at about 92% for all catalysts.