Catalyst Design Research
One of the major research avenues of our group is the study of the preparation of solid catalysts. A typical example is the platinum or rhodium containing automobile catalytic converter used to eliminate carbon monoxide, nitric oxide, and hydrocarbons from auto exhaust. Solid catalysts are usually composed of a metal or metal oxide deposited onto or -supported+ on a high surface area, refractory oxide, which produces small, well anchored metal particles with a maximum amount of exposed metal surface.
Our current efforts involve two aspects of catalyst preparation. First, we are trying to develop a scientific description for impregnation, the first step in catalyst preparation. In this process a salt of the desired metal is dissolved into water, and the support oxide is placed into this solution. We have revived a theory from the colloid science literature to predict how much metal will be adsorbed by the oxide for a full range of liquid conditions such as pH and metal concentration. We are currently in the process of a rigorous and systematic experimental verification of this theory.
In a second vein of work, we look at a further step of catalyst preparation. After impregnation and drying, the catalyst is put through a series of heat and chemical treatments to -activate+ the metal. We study how the shape and chemical structure of the deposited metal particles change as a function of pretreatment conditions. In some cases the size and shape of particles can be controlled. For these studies we use various types of characterization techniques such as electron microscopy and x-ray diffraction.
Lastly, we test the reactivity of the catalysts we produce, and attempt to relate their activity to their structure. We are working with a number of reactions having industrial, energy, and environmental significance.
