Kolkata, May 7 (IANS): Cars that run on air and puff out water vapour as exhaust? Well, Indian scientists claim solar energy can be integrated with unique devices called fuel cells to generate clean energy that could power green automobiles and much more.

At a time when carbon dioxide emissions from vehicles have come under the scanner for problems related to climate change, fuel cells are being seen as promising alternatives to fossil fuels.

And fuel cell vehicles are a reality now. In fact, in November last year, Toyota unveiled the Mirai, one of the first hydrogen fuel-cell vehicles to be sold commercially. Honda also displayed its sleek, new environmental friendly car engineered on the same principle.

"One of the major drawbacks of fossil fuel is that it generates greenhouse gas such as carbon dioxide. Also, due to incomplete combustion it produces a deadly poison like carbon monoxide," Swadhin Mandal, a scientist at Kolkata's Indian Institute of Science Education and Research, told IANS.

But in a fuel cell, hydrogen combines with oxygen to produce electricity, heat, and water - which makes it eco-friendly.

Due to the storage and safety concerns of hydrogen, the focus now is on hydrogen peroxide as the source.

Mandal and his collaborators at IISER-Kolkata and the Pune-based CSIR-National Chemical Laboratory have gone a step ahead to make the technology more energy-efficient.

According to the expert, by using solar energy tapped via photovoltaic cells, one could drive such fuel cells out of air.

"In principle, you can capture oxygen from air and use a photovoltaic cell to convert oxygen to hydrogen peroxide. So on a sunny day, you could use that to produce electricity and water," said Mandal, an associate professor at the institute's Department of Chemical Sciences.

The researchers have shown a new route that makes a hydrogen peroxide-based fuel cell 140 times more active.

Published online in the Journal of The American Chemical Society (JACS), the study is co-authored by students Anand Pariyar, Gonela Vijaykumar, Mrinal Bhunia, Suman Kumar Dey and Santosh K. Singh.

They have displayed the use of a novel iron-based substance to speed (act as a catalyst) up the energy generation - the key to the fuel cell's high performance.

"This makes the procedure not only energy efficient but also cost-effective since we did not use conventionally used platinum catalyst, which is very expensive. Moreover, hydrogen peroxide storage and transportation is very easy compared to hydrogen," said study co-investigator Sreekumar Kurungot from CSIR-NCL, Pune.

Mandal added: "Eventually, with more technological breakthroughs, hydrogen peroxide fuel cells should be able to power automobiles using oxygen from the air. In addition, the hydrogen peroxide-based fuel cell is now considered the best option for use as a power source at space stations, remote military camps and for underwater power requirements."