What is a Photocatalyst?

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About Photocatalyst

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 upon exposure to light. This phenomenon is known as photocatalysis.
The illumination of the catalyst causes the generation of free charges (electrons and holes) that can participate in chemical reactions, altering the reaction rate.
Photocatalysis includes reactions that take place by utilizing light and a semiconductor. All the photocatalysts are basically semiconductors.
There are various materials that show photocatalytic capability, and titanium dioxide (TiO2) is said to be the most effective.
The photocatalytic reactions can be categorized into two types based on the appearance of the physical state of the reactants.
- Homogeneous photocatalysis: When both the semiconductor and reactant are in the same phase, i.e. gas, solid, or liquid.
- Heterogeneous photocatalysis: When both the semiconductor and reactant are in different phases.
It is valuable for applications like air and water purification, self-cleaning surfaces, and even in some aspects of solar energy conversion.

Q1) What are photons?

Photons are fundamental subatomic particles that carry the electromagnetic force — or, in simpler terms, they are light particles.he photon is also the “quantum,” or fundamental unit, of electromagnetic radiation. Everyone is surrounded by photons: Like all other subatomic particles, photons exhibit wave-particle duality, meaning that sometimes they behave as tiny particles and sometimes they act as waves. Photons are massless, allowing them to travel at the speed of light in a vacuum.

Source: IISER Bhopal Researchers develop material to break down chemical warfare agents like Mustard Gas