A cutaway catalytic converter that you can pass around so that students can see the honeycomb structure that increases surface area. Great for heterogeneous catalysis and redox.
This demo is usually used during a unit on catalysis, but it could be used during a thermodynamics unit where you could investigate why the reactions only occur spontaneously at high temperatures. It's also a great consumer chemistry demo. Allow about 10 minutes for this demo.
Most modern cars are equipped with three-way catalytic converters. "Three-way" refers to the three regulated emissions it helps to reduce -- carbon monoxide, VOCs (volatile organic compounds), and NOx (the various nitrogen oxides) molecules.
2NO --> N2 + O2 or 2NO2 --> N2 + 2O2
2CO + O2 --> 2CO2
All of these reactions only occur at high temperatures after the engine has warmed up.1
cutaway catalytic converter
Display the catalytic converter and explain how it works. You might want to point out how the honeycomb structure increases surface area.
Don't drop it on your toe!