In a development especially relevant to India and Bangladesh, an international team of researchers has designed a nanomaterial that can be used to make "markedly more effective" catalytic converters for vehicles that could reduce car exhaust pollution.
Researchers at the University of Wollongong (UOW), in Australia, working with colleagues in Japan, Turkey, Bangladesh and at the Australian Nuclear Science Technology Organisation (ANSTO) have created a material that improves catalytic converter efficiency by "three to four times".
Catalytic converters reduce the pollution from vehicle exhaust by converting toxic gases and pollutants to less toxic pollutants. Among the pollutants, sulphur oxides and nitrogen oxides (NOX), badly impact photosynthesis of plants, damage immune system and generate reactive oxygen species (ROS) in the cells of affected organisms.
In a paper published in Nature Communications, the research team described how they created porous rhodium on a nanoscale. Rhodium is a chemical element commonly used in catalytic converters to reduce nitrogen oxides in exhaust gases. Making it porous increases its surface area, thereby making it more effective.
Lead author of the paper, Professor Yusuke Yamauchi from the Australian Institute for Innovative Materials (AIIM) at UOW said the porous rhodium nanoparticles could make a dramatic improvement to air pollution in cities around the world.
"At the moment, the conversion rate of our catalyst is three to four times that of a normal catalyst, the efficiency increase is three to four times," Yamauchi said.
Co-author Md. Shahriar Hossain, also from AIIM, said the new material could already be used to replace conventional catalytic converters, but the team was looking to develop it further to make it more efficient at converting other pollutants in addition to NOX.
"At this moment, with the conventional catalytic converter, we can simply replace it without any problem. You can just open the existing filters and put it in plug and play," Hossain said.
Hossain said he believed the technology could play a big role in reducing air pollution around the world, but saw it as being of particular benefit in South Asia and other parts of the developing world.
"In the West, people will be moving more and more to electric vehicles so there won't be the same problem. But in Bangladesh, in India and elsewhere in South Asia -- where already there are enormous problems with smog and air pollution from car exhausts -- petrol and diesel engines will continue to dominate for the next 50 or 60 years. This catalytic converter could really solve a lot of problems in that part of the world and we have recently started the collaboration with Bangladeshi researchers," he said.
The team is collaborating with researchers in Bangladesh to test this technology there in the agriculture sector.
"The problem is that while the NOX is converted to oxygen and nitrogen, the conversion also releases the carbon dioxide, which is very bad, so we also want to stop that. We think we can make a hybrid system that can decompose both NOX, SOX (sulphur oxide) and carbon dioxide, so that is the aim," Hossain explained.
Yamauchi said that because rhodium, a rare metal, is expensive, the team was also looking at testing different alloys to see if they could be of similar efficiency as converters.
"Iron and copper are very cheap materials so we will test some rhodium-copper and rhodium iron alloys -- if we can get the same efficiency with an alloy and at the same time lower the cost of the material then I think it will be more widely adopted," he said.
Co-author Tofazzal Islam, a plant biotechnologist, said this nanotech research breakthrough significantly reduces environmental pollution and indirectly improves the productivity of crops and other agricultural produces.
"This discovery highly benefit the developing countries like Bangladesh for maintaining higher agricultural productivity which is essential for ensuring food and nutritional security of this highly populated country," said Islam, Head of the Department of Biotechnology at Bangabandhu Sheikh Mujibur Rahman Agricultural University.
The study was partly supported by an Australian Research Council (ARC) Future Fellow, the UOW-ANSTO 2016 grant, and the AIIM-MANA 2016 grant. World Bank provided partial funding of this work through a sub-project of Higher Education Quality Enhancement Project (HEQEP).
Other co-authors are Bo Jiang, Cuiling Li, Omer Dag, Hideki Abe, Toshiaki Takei, Tsubasa Imai, Kathleen Wood and Joel Henzie.
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