Question

What is the meaning of catalyst? With examples

Answer 1

A catalyst is a substance that causes a chemical reaction to happen in a different way than it would happen without that catalyst - for example, a catalyst could cause a reaction to happen at a faster rate, or at a lower temperature, than would be possible without the catalyst.

A substance which when used in small amount in reactions modifies the rate of a reactionwithout being consumed in the reaction itself is known as a catalyst and this phenomenon is known as Catalysis. By using catalyst the rate of reaction is increased and we require lesser activation energy.

There are many good examples of catalysts. Some famous ones are:

1. The Iron catalyst used in the Haber-Bosch process, which is the main industrial process for ammonia production. This process is critical for world wide fertilizer production and is a multi-billion dollar industry that enables massive scales of global crop production. The catalyst is typically iron promoted with K22O, CaO, SiO22, and/or Al22O33. The original catalyst for this process used osmium, but that element is too rare and expensive for industrial use.
2. Chromium on silica (Cr/SiO22), “The Phillips Catalyst”, is responsible for half the world’s polyethylene production.
3. Tungsten on silica (W/SiO22) is used for industrial scale olefin metathesis. See the Shell Higher Olefin Process (SHOP).
4. The Grubbs' catalysts (a series of transition metal carbene complexes) are used as homogeneous catalysts for olefin metathesis
5. Gold nanoparticle catalysts for low temperature CO oxidation.
6. Amorphous MoS22 for water splitting