The Catalytic Converter The catalytic converter is a simple but fascinating invention that uses precious metals such as platinum, palladium and rhodium as a catalyst to cause reduction and oxidation reactions that can reduce the dangerous gases produced from combustion engines, converting over 95% of them into less harmful gases. Even though catalytic converters are quite simple, they are still extremely expensive, this is due to the precious metals used as catalysts. The reactions that take place to convert harmful gases into non-harmful gases could not happen without the right amount of energy, for a reaction to take place it must reach the correct activation energy. Activation energy is the minimum amount of energy that the reacting species must possess to undergo the specified reaction. The catalytic converter aids the thermodynamic process by decreasing the activation energy needed for the reaction to take place. The catalyst will not form a product but will change the rate of the reaction. The stainless steel housing of the catalytic converter contains two ceramic blocks, these blocks are honeycombed with hundreds of small passages. This honeycomb structure increases the surface area of ​​the catalytic converter, allowing multiple reactions to react simultaneously. The sides of these passages are coated with platinum, rhodium and palladium. These are very expensive metals, but when used correctly in a catalytic converter they are more than worth the cost. These metals are capable of reacting toxic gases and then recombining into harmless gases, all of this can be done without the precious metals deteriorating or rusting. The point of the honeycomb structure used in these ceramic plates is... in the center of the paper... these dangerously harmful gases would be released into our atmosphere by all combustion engines. Although the catalytic converter, when operating at its optimal temperature, can break down more than 95% of the harmful gases produced by the engine, it does not work well at all when it is not at high temperatures. It takes about five miles of driving for most vehicles to reach a temperature at which the reactions will be close to completion, before this temperature the catalytic converter does virtually nothing to convert these harmful gases. Some catalytic converters now come with coils that connect the engine to the catalytic converter to heat the catalytic converter to the optimal temperature right after the engine begins producing harmful gases. With this improvement the catalytic converter can effectively reduce almost all carbon monoxide and nitrogen oxide.