Catalysts and How They Work
How do they work?
A common misconception is that catalysts lower the activation energy of a reaction, whereas really, they are using an alternative route of the reaction in order for the bonds of the reactant to be broken with a lower activation energy.

The way catalysts situate this ‘alternative route’ is by binding to the reactant molecule and changing the electron configuration so that there is high electron density near the bond that are trying to be broken. As electrons have a -1 charge, they repel when within close proximity. The electromagnetic force then causes these electrons to repel, therefore breaking the bond at a lower activation energy level by using an ‘alternative route.’

An effective, yet simple analogy can be used to describe the way catalysts work, for example, take a steep, curved hill like the shoddy one you see below. The hill has a road starting from the foot of the left side and finishing on the foot of the right side of the hill. There is also a tunnel running through the hill. A car can go over the hill, resulting in the same finishing point as the tunnel despite taking longer and using more energy. The car could use the alternative catalyst route, which enables it to get from one side to the other in a shorter time period, without using as much energy.

The reactant, the car in this case will always have the tunnel, the catalyst to use, as during reactions catalysts remain unchanged throughout the reaction.
Where are they used?
Catalysts are used in everything from our body to large scale industrial process such as catalytic cracking. They are effective and used a lot as they can always be used again as catalysts remain chemically unchanged at the end of a reaction they work for. The biological catalyst amylase exists in all humans and it breaking down carbohydrates and maltose, as well as this, the catalyst zeolite is used in cracking chambers in order to break large useless alkanes into smaller more useful alkanes and alkenes. Shown by these two examples, catalysts are used everywhere because they save money and are often more environmentally friendly.
Why are they useful to chemists?
Catalysts are very useful to chemists and they are used in an array of different chemical reactions. Not only are they more practical as they remain unchanged at the end of a reaction, they provide the reactants with an alternative route which in turn means less energy is required for the reaction to take place. Because less energy is being used catalysts are environmentally friendly and they allow chemists to perform reactions at a lower energy cost and at a consistent rate.

Zeolite
Zeolite is a chemical catalyst that is used in the industrial process that occurs at most oil refineries, catalytic cracking. It is used as it allows the cracking of large, less useful alkanes into smaller more useful hydrocarbons. It allows catalytic cracking at around 500°C whereas thermal cracking, (a similar process without the catalyst zeolite) occurs at around 850°C. The temperature difference of 350°C saves a lot of energy, which results in a lot of money saved. This is why the catalyst zeolite is used in cracking. Below is a picture of zeolite. A substitute catalyst for zeolite is aluminium oxide.