Prospects of using carbon dioxide as a fuel by converting it into methane have become bright. The research on the matter was led by scientists at Duke University, who developed tiny nanoparticles of rhodium illuminated by ultraviolet light as a source of energy for the reaction.

The success from ultraviolet light has encouraged the researchers to try and create a new version of the nanoparticle to react with sunlight to produce new energy forms.

The research aims to set a milestone by trying to reduce the high levels of carbon dioxide in the atmosphere. Methane is the building block of most fuels.

According to the researchers, the rhodium nanoparticles turn highly efficient while reacting with UV light, with the extra advantage of forming methane directly without yielding any unwanted side-products including carbon monoxide.

The process gives hope that more light-driven catalysis in other chemical reactions can follow.

The study has been published in Nature Communications.

Rhodium has extensive applications in industrial processes, including those related to drugs and fertilizers, as it speeds up reactions by boosting energy.

The segment of chemical science that makes use of reactions of light with metals broken into nanoscales is called plasmonics.

Rhodium Nanocubes

For the experiments, rhodium nanotubes were synthesized by Xiao Zhang, a graduate student at the lab of Jie Liu, the George B. Geller professor of chemistry at Duke University and one of the researchers. The experiment involved passing carbon dioxide and hydrogen through small amounts of the nanoparticles in a reaction chamber.

Starting with heating, the process gave way to illuminating the nanoparticles with a high-power ultraviolet light. Under the UV process, researchers were surprised to see carbon dioxide and hydrogen reacting at room temperature and methane being produced.

"We discovered that when we shine a light on rhodium nanostructures, we can force the chemical reaction to go in one direction more than another," said Henry Everitt, study co-author and an adjunct professor of physics at Duke University.

The researchers also acknowledged better control of the chemical reaction and a greater ease in producing the desired product without unnecessary side-products when UV light was used.

Buoyed by the success, the team will now tweak the size of the rhodium nanoparticles to work with sunlight for integration into renewable energy systems.

Energy From Carbon Dioxide

Meanwhile, researchers at Penn State University have created a technology to create energy from carbon dioxide. Their process involves an inexpensive flow cell battery that uses a water solution of dissolved carbon dioxide or dissolved normal air. Through the technical process of sparging, the electricity is generated by the difference in pH levels of the two solutions.

The flow cell battery has two liquids separated by a membrane that disallows their mixing yet permits flow of ions. Merits of the battery by Penn State include the operation at room temperature and inexpensive materials, though more work needs to be done in improving performance.

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