• Question: @George whats Catalytic Chemistry.

    Asked by Teigan to George on 19 Nov 2014.
    • Photo: George Dowson

      George Dowson answered on 19 Nov 2014:

      Truly excellent question!
      There are two sides to catalysts. Firstly when you have a reaction you want to do, there’s the starting energy level of the reagents (starting materials) and the energy level of the products. If the starting energy level is higher than product one, the reaction is downhill so tends (but not always) to work, like rolling a rock down from the top of a hill to the bottom. However reactions usually break bonds or involve intermediate states that require high energy, so although the overall trip might be downhill, there may be a big energy barrier to get over called the activation energy. This is demonstrated in this cartoon:

      Catalysts can allow lower energy pathways and so can shink the activation energy “lump” making the reaction happen more easily, however they cannot make an uphill reaction happen or make a reavtion more energetic as that would either consume the catalyst (which means its not a catalyst) or break the laws of physics!

      The definimg characteristic of catalysts is that they are not consumed by a reaction. They go through cycles, going from resting to activated, then doing a reaction then releasing a product then turning back to the resting form. Sometimes each cycle can take a microsecond sometimes an hour, sometimes a catalyst (a bad one) can only do 10 cycles, others can do billions or even be unlimited. They’re like assembly line factories just the size of one molecule! They’re fascinating to work with and develop.