Researchers Find Way to Turn Carbon Dioxide into Valuable Fuel（在线收听）

Scientists blame greenhouse gases for being a major cause of climate change around the world. This is because greenhouse gases trap heat in the atmosphere and make the planet warmer.

Higher temperatures have caused major environmental problems on Earth, scientific research shows. These problems include loss of sea ice, rising sea levels, loss of ocean life and more intense weather events. Such problems are predicted to worsen unless governments around the world take action to reduce greenhouse gases.

Carbon dioxide is one of the major greenhouse gases. Most of this heat-trapping gas is produced through human activities related to burning fossil fuels for electricity, heat and transportation. Several major industries have attempted to move away from fossil fuels in favor of cleaner energy solutions.

Now, a team of researchers has announced a successful experiment that turned carbon dioxide into useful liquid fuel. The research was led by scientists from Rice University in the United States and was supported by the U.S. Department of Energy.

The findings were recently published in Nature Energy.

The researchers created a device, called a reactor, that converts carbon dioxide into a pure form of formic acid. Formic acid is a substance found in ants and some other insects, as well as in many plants. It is used as an antibacterial material and in the processing of some kinds of clothing.

Haotian Wang led the research team. He is a biomolecular engineer at Rice University. He said in a statement that the results of the experiment were important because formic acid is a major carrier of energy. So, the substance can provide a way to reuse carbon dioxide and prevent it from being released into the atmosphere.

“It’s a fuel-cell fuel that can generate electricity and emit carbon dioxide - which you can grab and recycle again,” Wang said.

Other methods for turning carbon dioxide into formic acid require intense purification processes, Wang said. Such methods are very costly and require a lot of energy. The Rice University team said it was able to reduce the number of steps used in the traditional process to create a low-cost, energy-saving method.

The researchers reported the reactor device performed with a conversion rate of 42 percent. This means that nearly half of the electrical energy can be stored in formic acid as liquid fuel.

The team said the reactor “was able to create formic acid continuously for 100 hours with little degradation” of the device’s parts.

Wang said the reactor could easily be changed to produce other high-value products, including alcohol-based fuels.

The researchers noted that the technology could also be a big help in solving another major energy problem – how to store large amounts of power in small places.

Wang said formic acid can be used as a better storage material for hydrogen, for example. Hydrogen is seen as a possible new energy source to power automobiles and trains. Hydrogen combines with oxygen to produce electrical power, and only releases water and steam into the atmosphere.

The researchers said their findings suggest formic acid “can hold nearly 1,000 times the energy as the same amount of hydrogen. Since hydrogen is difficult to shrink down and store, it currently presents “a big challenge for hydrogen fuel-cell cars,” Wang said.

He added that the team plans to keep working to improve the process. The team also aims to reduce the cost in hopes of bringing the technology to places around the world to help fight climate change.

"The big picture is that carbon dioxide reduction is very important for its effect on global warming,” Wang said. "If the electricity comes from renewable sources like the sun or wind, we can create a loop that turns carbon dioxide into something important without emitting more of it."

I’m Bryan Lynn.

Words in This Story

fossil fuel – n. a fuel, such as coal, oil, or natural gas, that is formed in the earth from dead plants or animals

emit – v. send out gas, heat, light, etc. into the air

grab – v. take hold of something

degradation – n. a worsening of quality

challenge – n. a difficult task or problem : something that is hard to do

renewable – adj. any naturally occurring source of energy, such solar or wind

loop – n. the repeating of something over and over