Scientists turn carbon dioxide back into fuel

•  Carbon dioxide is produced by the burning of fossil fuels in power plants and car engines and continues to accumulate in the atmosphere, warming the planet. But trees and other plants do slowly capture carbon dioxide from the atmosphere, converting it to sugars that store energy.
• In a new study from the U.S. Department of Energy's Argonne National Laboratory and the University of Illinois at Chicago, researchers have found a similar way to convert carbon dioxide into a usable energy source using sunlight.
• While plants use their catalysts to make sugar, the researchers used theirs to convert carbon dioxide to carbon monoxide.
• Although carbon monoxide is also a greenhouse gas, it is much more reactive than carbon dioxide and scientists already have ways of converting carbon monoxide into usable fuel, such as methanol.
• Although the reaction to transform carbon dioxide into carbon monoxide is different from anything found in nature, it requires the same basic inputs as photosynthesis.
• One of the chief challenges of sequestering carbon dioxide is that it is relatively chemically unreactive. On its own, it is quite difficult to convert carbon dioxide into something else.
• When converting carbon dioxide from the atmosphere into a sugar, plants use an organic catalyst called an enzyme.
• To make carbon dioxide into something that could be a usable fuel needed to find a catalyst - a particular compound that could make carbon dioxide react more readily.
• The researchers used a metal compound called tungsten diselenide, which they fashioned into nanosized flakes to maximise the surface area and to expose its reactive edges and ultimately create carbon monoxide.

Analysis:

• Carbon-dioxide levels in the Earth's atmosphere have fluctuated wildly for millennia; at one point billions of years ago, it was the dominant gas in the atmosphere. Today’s higher concentrations are the "unambiguous result of human emissions." Concentrations of carbon dioxide and other gases "are well above the natural range of atmospheric concentrations compared to the last 650,000 years.
• Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and natural gas.
• Governments are taking measures to limit emissions of carbon dioxide and other greenhouse gases like adopting different ways e.g., Kyoto Protocol, an agreement between countries that they will cut back on carbon dioxide emissions.
• According to an estimate, the average temperature of the earth has increased by 0.8 C in the last 130 years. It is predicted that if the global temperature rises by 3.60 C, the polar ice caps and glaciers would melt. This would increase the water level of oceans by about 100 m and hence lead to the flooding of low-lying coastal areas of the earth.

By: Vishal