A catalytic converter is a device that was created in the early 80's. It is designed to reduce the amount of harmful elements expelled from a running combustion vehicle. Over the past fifteen years this device has dramatically decreased the amount of pollution created by vehicles, while still remaining as fuel-efficient. 

Most Catalytic converter are located directly in the exhaust system.

Some are located on a side system next to the direct exhaust line so that they can be turned on or off. Most catalytic converters are located closer to the engine of the car, so that the emissions are still vaporized when they pass through the filter. Although there are different types of converters, the standard converter is about the size of two 2L pop bottles place next to each other.

The elements that are expelled from a standard combustion vehicle are shown in the table below.

Element Outline

Nitrogen Gas (N2) Air that passes through engine consists of 78 % N2.
Carbon Dioxide (CO2) Created by a bond between Carbon and Oxygen during combustion.
Water vapor (H2O) Hydrogen and Oxygen bond during combustion. 
Carbon Monoxide (CO) Poisonous and colourless gas.
Hydrocarbons (VOCs) Fuel that is not fully combusted is evaporated, creating VOCs. 
Nitrogen oxides (NO, NO2 = NOx) Factor in smog, acid rain and irritation of human mucus membranes.

A standard catalytic converter used today uses a "three way system" to remove CO, VOCs and NOx molecules. A converter consists of two catalysts, a Reduction Catalyst (A) and an oxidation catalyst (B). Catalysts consist of ceramic and metal (Platinum, Rhodium and/or palladium) configured in a honeycomb pattern (C). The converter is designed to cover the maximum surface volume of emissions while using the smallest amount of metal.

Section (A) of the catalytic converter is called the reduction catalyst; it consists of Platinum and Rhodium. The reduction Catalyst separates the Nitrogen atoms from the NO or NO2 gas and leaves the oxygen to form O2, the remaining N atoms are bonded together to form N2. Section (B) of the catalytic converter is called the Oxidation Catalyst. The Oxidation Catalyst burns the remaining VOCs over a platinum surface, this reacts the hydrocarbons with the remaining oxygen forming 2CO2. 

Most catalytic converters are equipped with a sensor computer injection system. This is located in the main output before the converter. It measures how much oxygen is being pumped into the converter and adjusts the air/fuel ratio to inject at a 14.7:1. 

Conclusion:

The Catalytic converter is an effective way to reduce the amount of CO, VOCs, and NOx molecules produced by a vehicle. In addition it is a relatively cost efficient system to reduce pollution compared to integrating electric, bio-diesel, fuel cell, and/or natural gas vehicles into our current production line. Therefore, Catalytic converters are in human kinds best interest and create a safer atmosphere to live and breath in for all living creatures.