Easily Recycled CuMgFe Catalysts Derived from Layered Double Hydroxides for Hydrogenolysis of Glycerol

Xiaopeng Yu,Yi Wang,Fubao Zhang,Dejun Cheng

doi:10.3390/catal11020232

Abstract

A series of CuMgFe catalysts with different (Cu + Mg)/Fe molar ratios derived from hydrotalcites were prepared by coprecipitation for the hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO). X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), vibrating sample magnetometer (VSM), hydrogen temperature-programmed reduction (H2-TPR), CO2-TPD, and H2-TPD (temperature-programmed desorption of CO2 and H2) were used to investigate the physicochemical properties of the catalysts. The CuMgFe-layered double oxides (CuMgFe-4LDO) catalyst with (Cu + Mg)/Fe molar ratio of 4 exhibited superior activity and stability. The high glycerol conversion and 1,2-propanediol selectivity over CuMgFe-4LDO catalyst were attributed to its strong basicity, excellent H2 activation ability, and an increase in the surface Cu content. The CuMgFe catalysts could be easily recycled with the assistance of an external magnetic field due to their magnetism.

Highlights

The CuMgFe-layered double oxides (CuMgFe-4LDO) catalyst with (Cu + Mg)/Fe molar ratio of 4 exhibited superior activity and stability
CuMgFe-4LDH and CuMgFe-5LDH exhibited a lower crystallization with the increase of evidenced a better crystallization of the phase of hydrotalcite
Increasing (Cu + Mg)/Fe molar ratio might lead to the structural and CuMgFe-5LDH exhibited a lower crystallization with the increase of (Cu + Mg)/Fe distortion and the orderliness decline of hydrotalcite

Summary

Introduction

The CuMgFe-layered double oxides (CuMgFe-4LDO) catalyst with (Cu + Mg)/Fe molar ratio of 4 exhibited superior activity and stability. The conversion of excess glycerol into higher-value chemicals can increase the economic value of the biodiesel industry Different processes such as oxidation, dehydration, and hydrogenolysis have been proposed for the conversion of glycerol [1,2,3,4,5]. Noble metals such as Rh, Ru and Pt are extensively used in the hydrogenolysis of glycerol owing to their high reactivity [9,10,11,12,13,14,15] These catalysts usually facilitate excessive C–C cleavage, resulting in a poor selectivity to 1,2-PDO. Thermal decomposition of LDHs leads to the formation of mixed oxides with small crystal size, basicity, high dispersion, and large specific surface area

Objectives

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Conclusion