Abstract
Nickel-based carbide catalysts combined with four different metals (Mo, Nb,W, and Zr) and supported on Al-SBA-15 were investigated for the hydrocracking of distillers dried grains with solubles (DDGS) corn oil to produce biofuels under mild reaction conditions. The effects of the fractional sums of the electronegativities of the transition metals on the catalyst activities, selectivities, and stabilities were investigated. The closer the fractional sum of the transition metal electronegativities was to the electronegativity range of the noble catalysts (2.0-2.2), the better was the catalyst performance. The highest diesel selectivity was obtained from NiWC/Al-SBA-15, with a fractional sum of electronegativity of 2.06. The effects of doping a promoter (Ce) on the catalyst electronegativity and activity were studied. Adding Ce generally improved the catalyst performance, by adjusting the combined electronegativities nearer to 2.0-2.2. However, other parameters affected by Ce addition, such as textural properties, or the performance of individual metals could also impact catalyst performance. The NiNbC/Al-SBA-15 catalyst promoted with 5% Ce maintained stable activity for 168 h at 400 degrees C and 4.48 MPa H-2. (C) 2014 Elsevier B.V. All rights reserved.