Glycerol Steam Reforming over Bimetallic Co−Ni/Al2O3

Abstract

Glycerol steam reforming has been performed in a fixed-bed microreactor containing bimetallic Co−Ni/Al2O3 catalyst using a wide range of steam-to-glycerol ratios (3 ≤ STGR ≤ 12) for reaction temperatures between 773 and 823 K at atmospheric pressure. Physicochemical characterization revealed the presence of both Lewis and Bronsted acid sites on the catalyst although the catalyst appears to have a net surface acidity (acid:basic site concentration ratio = 9.0). Co and Ni oxides as well as the metal aluminates were identified from XRD pattern with crystallite size (131.5 nm) similar to that obtained from H2 chemisorption experiments (136.0 nm). Glycerol consumption rate data analysis implicates fractional orders with respect to both glycerol (0.25) and steam (0.36) with an activation energy of 63.3 kJ mol−1. Similar treatment for H2, CO2, CO, and CH4 production rate evinced positive fractional orders for both reactants with the exception of CO which has mild inhibition by steam (−0.065). Mechanistic conside...