In a big push for solar fuel, Govinder Singh Pawar has created a semiconductor that can store solar energy more efficiently than any other method we know today.
New Delhi: Indian-origin scientist Govinder Singh Pawar has possibly pushed the world one giant step closer to moving to a pollution-free world. In a big push for solar fuel, Pawar has created a photoelectrode — a semiconductor that can both store solar energy more efficiently than any other method we know today and also use it to generate enough voltage to extract hydrogen from water — for fuelling our world.
A scientist at the University of Exeter, Britain, Pawar said he has been working on this project as his PhD for the past two and a half years. Over 85 per cent of the world’s energy today is sourced from fossil fuel all over the world. “The amount of energy we consume today is only half of what it is expected to be in 2050,” he explained in his new paper that was published in the science journal ‘Nature’ earlier in February.
Given the looming threat of climate change and incessant human fight over oil, the time is way past for us to have found a sustainable, alternative source of fuel that is scalable and can be implemented widely. This need held Pawar’s attention.
Pawar’s parents immigrated to Britain over 20 years ago. He studied chemistry in college, finishing with a Master’s at Loughborough University. In his third and fourth year at college, Pawar realised he was most captivated by his research projects when they related to energy.
“I was always interested in electrochemistry and physical chemistry,” he said. “New sources of energy for the future in a ‘green’ and sustainable way had interested me greatly. I wanted to pursue a PhD related to that.”
And so he married his two interests and set out to help solve one of our planet’s biggest problems. Now he works under the guidance of Dr. Asif Tahir, who also supervised him for this paper.
Through humankind’s travails with wind, water, and solar energy, the pot of gold at the end of this sustainable energy rainbow is anti-climactically the most common element in our universe – hydrogen. This would be our ideal energy source for the future.
Hydrogen fuel is a zero-emission fuel that is clean and is completely capable of replacing carbon energy sources. Despite the fact that nearly every star we see is almost entirely made of it, molecular hydrogen is very hard to come by on earth. One of the few ways it can be effectively produced is by extracting it from water.
Splitting water into oxygen and hydrogen is a process called ‘artificial photosynthesis’, which essentially replicates what plants around us do within their complex, invisible systems. However, the bigger problem is cost-effective production and storage of fuel. The amount of energy required to split water is so high, that process requires a sustainable energy source itself.
In his laboratory, Pawar and Tahir have created a semiconductor that has eluded cost-effective production for years. The semiconductor can both store solar energy and then also produce energy to split the water. The material is made of Lanthanum orthoferrite, or LaFeO3, and is today the best material that can be used for artificial photosynthesis. It absorbs more sunlight than any other material tested before, uses it to split water, and then store the hydrogen fuel.
Materials being used currently are either too expensive, use toxic chemicals, have excessively complicated structures, are unstable, or use expensive techniques like coating with an atom-sized layer of metals to improve performance. The semiconductor material Pawar developed took several iterations and a very long time to arrive at just the right combination and order of plating, coating, spraying, and heating.
Pawar’s results spell great news. “My paper shows that we are able to produce semiconductor materials which are non-toxic, inexpensive, stable, and scalable,” he said. Most importantly, it can produce hydrogen without an external catalyst; all that is needed is sunlight and water.
Pawar is currently collaborating with researchers at IIT-Madras, who are tackling the problem of making the material absorb even more solar energy than it does now. At the moment, the amount of sunlight it can absorb is a limitation. “If it can absorb more light, it would be able to produce more hydrogen,” he said. “The next step is to improve the materials light absorption capabilities for more hydrogen generation, which we are currently working on.”
Further research could potentially make Pawar’s results scalable enough to implement on an experimental basis in vehicles and heating homes. Britain has been ahead of the curve, several trucks today already run on a hydrogen-diesel mix and the country has seen reduced emissions. Several Scandinavian countries have hydrogen powered public buses. Norway has plans to move to an entirely hydrogen-fuelled home heating system. Turkey has been doing heavy work in the area too.
Pawar’s material, if scaled well, could one day potentially be an effective cost-saving technique to propel a large part of the world into a hydrogen economy.
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19 December 2018
20 December 2018