Nickel catalysts for the hydrodeoxygenation of biodiesel

Abstract

A number of nickel and nickel-copper catalysts for the hydrodeoxygenation of fatty acid esters (biodiesel) were studied. The CeO2 and ZrO2 oxides and the CeO2-ZrO2 binary system were used as supports. The Ni-Cu/CeO2-ZrO2 catalyst exhibited the highest activity; it allowed us to quantitatively convert biodiesel into linear alkanes under mild conditions (290–320°C, 1.0 MPa). It was found that the selectivity of the formation of the main product (heptadecane) was 70–80%. The main correlations between the nature of catalysts and their activity under conditions of the target reaction were determined using temperature-programmed reduction, X-ray diffraction analysis, and electron microscopy. It was hypothesized that the high activity of Ni-Cu/CeO2-ZrO2 in the test reaction can be explained by the presence of a Ni1 − x Cu x (x = 0.2–0.3) solid solution as a constituent of the active component of the catalyst.