Artificial leaf
Scientists have designed a means of using solar energy to convert water into hydrogen and oxygen efficiently, using an artificial "leaf." Creative Commons

Scientists may be one step closer to making hydrogen a commercially viable and cheap fuel, paving the way for a clean and green future.

Hydrogen-fuel technologies available in the market are not energy efficient, which renders them unsuitable for large-scale use.

However, scientists from Arizona State University (ASU) have managed to overcome this limitation.

A study by researchers in the university, which was published in Nature Chemistry journal, illustrates the chemical reactions that convert water into hydrogen and oxygen without requiring excessive energy using a solar energy-based artificial "leaf".

The "leaf" is designed to use a chemical pathway similar to that of photosynthesis in plants to oxidise water into oxygen and free hydrogen, according to the study, which was led by Jackson Megiatto.

"Initially, our artificial leaf did not work very well, and our diagnostic studies on why indicated that a step where a fast chemical reaction had to interact with a slow chemical reaction was not efficient," Professor Thomas Moore of ASU said in a statement.

"The fast one is the step where light energy is converted to chemical energy, and the slow one is the step where the chemical energy is used to convert water into its elements hydrogen and oxygen."

"We looked in detail and found that nature had used an intermediate step," Moore continued.

The researchers replicated electron relay of the photosynthetic pathway and observed a marked improvement in the efficiency of the reaction.

"This intermediate step involved a relay for electrons in which one half of the relay interacted with the fast step in an optimal way to satisfy it, and the other half of the relay then had time to do the slow step of water oxidation in an efficient way."

Scientists are hoping that this new development will go a long way in fulfilling the need for an economically viable clean energy source.

If hydrogen could be procured safely and economically, it can be used to fuel combustion engines of spacecraft, airplanes and vehicles.

"[Hydrogen] is an environmentally friendly fuel that has the potential to reduce our dependence on imported oil," a US Department of Energy paper said.

The burning of hydrogen does not generate air pollutants or even greenhouse gases, and is a much cleaner alternative to petroleum.