Fourth Meeting of the
Catalysis Club of Chicago 2009-2010
Monday, January 11, 2010

Location TBA

Cost $45 Professionals
$20 Students/Post Docs

A Novel Combustion Synthesis Method for Preparing Active and Selective-High Area Multicomponent Catalysts for Hydrogen Production from Bio-alcohols

Professor Eduardo Wolf
Department of Chemical and Biomolecular Engineering
University of Notre Dame
Notre Dame, IN 46556 USA

Web Site of Professor Wolf

Abstract

A novel method for catalysts synthesis is described to prepare multi-component catalysts for hydrogen production from methanol and ethanol. In this method, referred as Impregnated Layer Combustion Synthesis (ILCS) a reactive solution containing the catalysts' precursor and a fuel, such as glycine, is impregnated into a thin cellulose paper or into a porous support. After drying, the cellulose is ignited at one end resulting in a combustion front that moves in a self-sustained mode leaving behind the desired oxides with high surface area. A high speed IR camera (FLIR SC6000) as well as a conventional visible range camcorder, are used to follow the temperature–time evolution during combustion and determine the composition and textural and crystalline characteristics of the materials thus prepared.

Complex catalysts containing copper, zinc, zirconium in a molar ratio of 7/3/1 were prepared by ILCS. The activity and selectivity of these catalysts for hydrogen production from the oxidative reforming of methanol was measured under various conditions. Pd was added into the mixture during ILCS or by a subsequent impregnation of a previously synthesized Cu/Zn/Zr catalyst (second wave impregnation or SWI). Pd promotion increased the low temperature activity but did not affect significantly hydrogen selectivity. Preparations with Pd added by SWI yielded catalysts with exceptional high activities for methanol conversion giving 40% conversion at just 70°C. We attribute this effect to the increase in Pd dispersion. When the Cu/Zn/Zr-Pd catalyst was supported on zirconia they have high surface area and their conversion and hydrogen selectivity increased at low temperature. A model of the combustion synthesis process for catalysts preparation is discussed. Characterization results correlating the catalytic role of the various components during methanol oxidative reforming are also discussed.

We also report the application of volume combustion synthesis (VCS) to prepare catalysts for hydrogen production from bio-ethanol. Catalysts containing Ni, Fe, and Cu were prepared from an aqueous solution of their nitrate precursors and variable amounts of glycine as a fuel and reducing agent. This solution was then heated over a hotplate heater resulting in the ignition of the mixture as a whole to yield crystalline materials with the desired composition. The amount of glycine was optimized to get pure metals as well as metal oxides. These catalysts were found to be very effective for ethanol decomposition as well as ethanol partial oxidation. Hydrogen production started as 116 °C and gives ~ 50% conversion and ~ 50% hydrogen selectivity at 250 °C. Further work is underway to characterize these catalysts and correlated their structural and surface properties to activity and selectivity.