The reaction of pure hydrogen gas (H2) with oxygen (O2) in the air forms water (H2O) and also releases energy in the process. This energy can be used as fuel. Dr Govinder Singh Pawar, a scientist at the University of Exeter, UK, is leading the research to make the fuel obtained from photosynthesis (or water-splitting) a reality. In fact, the team has already developed the material for the same. The only by-product of this clean energy source? Water! A researcher from the team said, "Our material has excellent stability where, after 21 hours of testing, it does not degrade, ideal for water splitting purpose."

Hydrogen is one of the lightest elements in the periodic table, and due to its simple composition, it is also the most abundant element in the universe. It is also believed to be one of the first elements to be ever formed after the Big Bang. Hydrogen, though the simplest, packs a punch. Hydrogen gas is highly flammable, and very powerful when mixed with oxygen or chlorine. In fact, it is so robust that the mixture is used to launch rockets into orbit. When a flame of pure hydrogen gas (H2) burns in air, it reacts with oxygen (O2) to form water (H2O) and releases energy, which can be used as a fuel. This hydrogen fuel is a zero-emission fuel when burned with oxygen, and the only by-product is water. Though the process seems easy and energy-efficient, the challenge is to obtain clean hydrogen.

Hydrogen doesn't occur naturally on earth. And since it is so light, it rises in the atmosphere and is therefore rarely found in its pure form. But there is one manner in which this process has been occurring for millions of years. Photosynthesis in plants is the process that splits molecules in water, using sunlight. Photoelectrolysis, also known as water-splitting, uses electrolysis of water by light, where photoelectrodes actuate the process of splitting the hydrogen from oxygen by mimicking photosynthesis. The photoelectrodes are crucial in determining the efficiency of the process. And the challenge lies here, in identifying stable, low-cost semiconductors that can act as photoelectrode, to meet the thermodynamic and kinetic criteria for photoelectrolysis.

Hydrogen from this can form the basis of renewable energy and can provide a sustainable pathway for true transformation of environmental challenges. We are at a time where 85% of energy comes from burning exhaustible fossil fuels. This invention of the semiconductor can result in clean energy which is transportable and storable.

Source: https://www.thebetterindia.com/142537/indian-origin-scientist-team-fuel-from-sunlight/