New method from IIT Guwahati helps produce sustainable green hydrogen fuel

Guwahati: A catalyst that can release hydrogen gas from wood alcohol, with no side production of carbon dioxide has been developed by researchers at the Indian Institute of Technology (IIT) Guwahati. The research, published in the journal ACS Catalysis, opens up exciting avenues for the development of the hydrogen-methanol economy.

Beyond being an easy and environmentally safe process, the method produces formic acid which is a useful industrial chemical. This development makes methanol a promising 'Liquid Organic Hydrogen Carrier' (LOHC) and contributes to the concept of hydrogen-methanol economy.

As the world is moving towards finding alternatives to fossil fuels, hydrogen gas continues to be the best source of clean energy generation. Currently, hydrogen is produced either by the electrochemical splitting of water or from bio-derived chemicals such as alcohol.

In the new method, hydrogen is typically produced from methyl alcohol (commonly called wood alcohol) using a catalyst, in a process called methanol reforming. There are two problems with the catalytic production of hydrogen from wood alcohol. The first is that the process involves high temperatures in the range of 300 degrees Celsius and at high pressures. Secondly, the reaction co-produces carbon dioxide, which is a greenhouse gas. This is where the team has found a solution.

"In methanol-reforming, in stark contrast to well-reported catalytic systems that act like brahmastra and result in complete destruction to carbon dioxide, the current work involves a smart strategy to design pincer (crab-like) catalysts that selectively produce high-value formic acid and clean-burning hydrogen," said Dr Akshai Kumar AS, Associate Professor, Department of Chemistry at IIT Guwahati, in a statement.

The team developed a special form of catalyst called the 'pincer' catalyst, which contains a central metal and a few specific organic ligands. It is called a pincer because the organic ligands are like the claws of a crab that hold the metal in place.

Because of this special arrangement, the catalyst becomes very specific and selective.

Thus, as wood alcohol is broken into hydrogen, formic acid is generated instead of carbon dioxide. The reaction takes place at 100 degrees Celsius, much lower than the temperatures required for conventional methanol-reforming. To make the catalyst reusable, the researchers loaded the catalyst on an inert support. By this, they could reuse the catalyst over many cycles.

The novel catalytic system which produces hydrogen and formic acid from wood alcohol is a step towards achieving the Global goal of decarbonisation of the planet set for 2050, the study showed.