• Question: how would you convert the solar energy into fuel using simple terms

    Asked by loch2591 to Stephen on 9 Nov 2017.
    • Photo: Stephen Rhatigan

      Stephen Rhatigan answered on 9 Nov 2017:


      The method that I study is a called photo-catalysis. There are a number of different reactions which can make different fuels but to keep things simple let’s focus on one: splitting water to produce hydrogen fuel.
      So in an ideal world you need three things:
      1. Sunlight – check (not so much in Ireland).
      2. Water – check.
      3. A photo-catalyst material – they exist but the efficiency isn’t great.
      Now let’s break down the process into steps:
      1. The sun shines on the photo-catalyst material.
      2. The photo-catalyst absorbs the energy from the sunlight (actually electrons in the material absorb the energy).
      3. The energy is transferred to the surface of the material where there are water molecules present.
      4. The energy is transferred to the water molecules, breaking them apart (there are many steps involved in this process but the end result is hydrogen gas and oxygen gas).
      5. Now the energy is stored (mostly) in the bonds of the hydrogen gas.
      6. When the hydrogen and oxygen are recombined the energy is released and you have water again.
      I hope that explanation helps and there is a picture on my profile which might make things easier to imagine (under the “my work” heading). If not please leave a comment and I’ll try again.

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