Photocatalysis
2023 JAN 14
Preliminary >
Science and Technology > Innovation and New technologies > Innovation and New technologies
Why in news?
- Recently, a study has reported a way to achieve a relatively high efficiency in an artificial photosynthesis reaction in which water is split into oxygen and hydrogen using sunlight and a catalyst. The technique is called photocatalysis.
What is Photocatalysis?
- The term photocatalyst is a combination of two words: photo related to photon and catalyst, which is a substance altering the reaction rate in its presence.
- Therefore, photocatalysts are materials that change the rate of a chemical reaction on exposure to light. This phenomenon is known as photocatalysis.
- Photocatalysis includes reactions that take place by utilizing light and a semiconductor.
- The substrate that absorbs light and acts as a catalyst for chemical reactions is known as a photocatalyst.
- All the photocatalysts are basically semiconductors.
- Photocatalysis is a phenomenon, in which an electron-hole pair is generated on exposure of a semiconducting material to light.
About Photocatalytic STH:
- Photocatalytic STH (solar-to-hydrogen) is inspired by photosynthesis, where leaves use energy from incident sunlight to split water into oxygen and hydrogen.
- The process consists of a semiconductor photocatalyst wafer immersed in freshwater or seawater.
- When photons in sunlight strike the water, they dislodge electrons in its atoms, which trigger a redox reaction in the water and separate hydrogen and oxygen.
- The energy source is sunlight and the feedstock is water – both abundant on Earth and green by nature.
Significance:
- Considering electricity is the biggest component of the cost of green hydrogen, the government effectively needs cheaper renewable energy – the breakthrough could also come from cutting-edge technologies like photocatalysis.
PRACTICE QUESTION
Consider the following statements:
1. Photocatalysts are materials that change the rate of a chemical reaction on exposure to light
2. All the photocatalysts are basically semiconductors
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer