Catalytic performance of organically templated nano nickel incorporated-rice husk silica in hydroconversion of cyclohexene and dehydrogenation of ethanol

Abstract Rice husk silica (RHS) was extracted from local rice husk by acid digestion and burning at 650 °C. RHS-Ni catalyst was prepared by dissolving RHS in 1 N NaOH and titrating with 3 N HNO 3 containing 10 wt.% Ni 2+ . The organic modifiers, either p -amino benzoic acid (A) or p -phenylenediamine (PDA) were incorporated in 5 wt.% and reduced in H 2 flow. Investigation of the three catalysts, (RHS-Ni) R350 , (RHS-Ni–A) R350 and (RHS-Ni–PDA) R350 , confirmed good dispersion of Ni nanoparticles; all catalysts were amorphous. The BET surface areas increased in the order: (RHS-Ni) R350 R350 R350 with controlled pore sizes. The as-prepared catalysts were applied for both hydroconversion of cyclohexene with molecular H 2 and ethanol dehydrogenation, using a flow-type reactor, at different temperatures. The activity in cyclohexene hydroconversion and selectivity to cyclohexane depended upon the reaction temperature; at t 2 –Ni–amine complex, pore regulation as a prime requirement for H 2 storage and homogeneous distribution of incorporated Ni nanoparticles. At t  > 150 °C, the backward dehydrogenation pathway was more favored, due to unavailability of H 2 ; the process became structure-sensitive. In ethanol conversion, the prevailing dehydrogenation activity of organically modified catalyst samples was encouraged by improved homogeneous distribution of Ni nanoparticles and created micropre system.