Influence of crystal of Fe2O3 in magnetism and activity of nanoparticle CaO@Fe2O3 for biodiesel production

Two different crystals of Fe2O3 prepared with and without KNO3 were respectively used as magnetic cores for supporting CaO, which were designated as CaO@gamma-Fe2O3 and CaO@ hematite Fe2O3. The comparison of catalytic performance of both catalysts was studied by transesterification of soybean oil and methanol. The differences of two catalysts samples in the aspects of morphology, magnetism and basicity were investigated by XRD, SEM, CO2-TPD and VSM spectroscopy. CaO@gamma-Fe2O3 with the yield of 98.8% performed higher catalytic activity than CaO@ hematite Fe2O3 due to better stereo properties, stronger magnetic properties and stronger basicity. In addition, CaO@gamma-Fe2O3 catalyst also performed better acid-resistance and recyclability, which represented a highly efficient alkaline heterogeneous catalyst for its universally application. (C) 2017 Elsevier Ltd. All rights reserved.