Chemical Concepts Demonstrated

• Heat-based catalysis
• Use of a ceramic as the solid support for a catalyst

Demonstation

The catalytic combustion unit consists of a glass tube with a honeycomb block of ceramic coated with a noble metal (platinum and/or palladium) inside. The catalytic combustion unit is heated with a Bunsen burner until the bottom starts to glow red. The gas is then quickly shut off, the burner is inserted into the glass tubing, and the gas is turned on again.

Observations

The bottom continues to glow red hot.

Explanation

The catalyst in this situation is the ceramic/metal block.  It catalyses the oxidation of whatever fuel that the Bunsen burner happens to be running off of.  The product from this oxidation is not flammable, and a match would go out if it were held above the unit.

Catalytic combustion units are used on such devices as automobiles and wood-burning stoves.  When the fuel in these devices is combusted, there is a chance that the combustion will be incomplete.  Combustion units such as these complete the oxidation of these fuels and, as a result, produce more heat and less pollutants.

Contributors

• Dr. George Bodner (Perdue University)

   

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