Ionic Liquid Catalyst Helps Turn Emissions Into Fuel

Biofuel production (left) compared to fuel produced via artificial synthesis. Crops takes in CO2, water and sunlight to create biomass, which then is transferred to a refinery to create fuel. In the artificial photosynthesis route, a solar collector or windmill collects energy that powers an electrolyzer, which converts CO2 to a synthesis gas that is piped to a refinery to create fuel. (Credit: Graphic by Dioxide Materials)

Science Daily  — An Illinois research team has succeeded in overcoming one major obstacle to a promising technology that simultaneously reduces atmospheric carbon dioxide and produces fuel.

Artificial photosynthesis is the process of converting carbon dioxide gas into useful carbon-based chemicals, most notably fuel or other compounds usually derived from petroleum, as an alternative to extracting them from biomass.

University of Illinois chemical and biological engineering professor Paul Kenis and his research group joined forces with researchers at Dioxide Materials, a startup company, to produce a catalyst that improves artificial photosynthesis. The company, in the university Research Park, was founded by retired chemical engineering professor Richard Masel. The team reported their results in the journal Science.

In plants, photosynthesis uses solar energy to convert carbon dioxide (CO₂) and water to sugars and other hydrocarbons. Biofuels are refined from sugars extracted from crops such as corn. However, in artificial photosynthesis, an electrochemical cell uses energy from a solar collector or a wind turbine to convert CO₂ to simple carbon fuels such as formic acid or methanol, which are further refined to make ethanol and other fuels.

"The key advantage is that there is no competition with the food supply," said Masel, a co-principal investigator of the paper and CEO of Dioxide Materials, "and it is a lot cheaper to transmit electricity than it is to ship biomass to a refinery."

However, one big hurdle has kept artificial photosynthesis from vaulting into the mainstream: The first step to making fuel, turning carbon dioxide into carbon monoxide, is too energy intensive. It requires so much electricity to drive this first reaction that more energy is used to produce the fuel than can be stored in the fuel.

The Illinois group used a novel approach involving an ionic liquid to catalyze the reaction, greatly reducing the energy required to drive the process. The ionic liquids stabilize the intermediates in the reaction so that less electricity is needed to complete the conversion.

The researchers used an electrochemical cell as a flow reactor, separating the gaseous CO₂ input and oxygen output from the liquid electrolyte catalyst with gas-diffusion electrodes. The cell design allowed the researchers to fine-tune the composition of the electrolyte stream to improve reaction kinetics, including adding ionic liquids as a co-catalyst.

"It lowers the overpotential for CO₂ reduction tremendously," said Kenis, who is also a professor of mechanical science and engineering and affiliated with the Beckman Institute for Advanced Science and Technology. "Therefore, a much lower potential has to be applied. Applying a much lower potential corresponds to consuming less energy to drive the process."

Next, the researchers hope to tackle the problem of throughput. To make their technology useful for commercial applications, they need to speed up the reaction and maximize conversion.

"More work is needed, but this research brings us a significant step closer to reducing our dependence on fossil fuels while simultaneously reducing CO₂ emissions that are linked to unwanted climate change," Kenis said.

Graduate students Brian Rosen, Michael Thorson, Wei Zhu and Devin Whipple and postdoctoral researcher Amin Salehi-Khojin were co-authors of the paper. The U.S. Department of Energy supported this work.

Ancient Supernovas Discovered: 10-Billion-Year-Old Exploding Stars Were a Source of Earth's Iron, Researchers Say

One of ten supernovas in the Subaru Deep Field, which exploded 10 billion years ago. (Credit: Tel Aviv University.)

Science Daily — Supernovas -- stars in the process of exploding -- open a window onto the history of the elements of Earth's periodic table as well as the history of the universe. All of those heavier than oxygen were formed in nuclear reactions that occurred during these explosions.

The discovery sharpens our understanding of the nature of supernovas and their role in element formation, say study leaders Prof. Dan Maoz, Dr. Dovi Poznanski and Or Graur of TAU's Department of Astrophysics at the Raymond and Beverly Sackler School of Physics and Astronomy. These "thermonuclear" supernovas in particular are a major source of iron in the universe.

The most ancient explosions, far enough away that their light is reaching us only now, can be difficult to spot. A project spearheaded by Tel Aviv University researchers has uncovered a record-breaking number of supernovas in the Subaru Deep Field, a patch of sky the size of a full moon. Out of the 150 supernovas observed, 12 were among the most distant and ancient ever seen.

The research, which appears in the Monthly Notices of the Royal Astronomical Society this month, was done in collaboration with teams from a number of Japanese and American institutions, including the University of Tokyo, Kyoto University, the University of California Berkeley, and Lawrence Berkeley National Laboratory.

A key element of the universe

Supernovas are nature's "element factories." During these explosions, elements are both formed and flung into interstellar space, where they serve as raw materials for new generations of stars and planets. Closer to home, says Prof. Maoz, "these elements are the atoms that form the ground we stand on, our bodies, and the iron in the blood that flows through our veins." By tracking the frequency and types of supernova explosions back through cosmic time, astronomers can reconstruct the universe's history of element creation.

In order to observe the 150,000 galaxies of the Subaru Deep Field, the team used the Japanese Subaru Telescope in Hawaii, on the 14,000-foot summit of the extinct Mauna Kea volcano. The telescope's light-collecting power, sharp images, and wide field of view allowed the researchers to overcome the challenge of viewing such distant supernovas.

By "staring" with the telescope at the Subaru Deep Field, the faint light of the most distant galaxies and supernovas accumulated over several nights at a time, forming a long and deep exposure of the field. Over the course of observations, the team "caught" the supernovas in the act of exploding, identifying 150 supernovas in all.

Sourcing man's life-blood

According to the team's analysis, thermonuclear type supernovas, also called Type-la, were exploding about five times more frequently 10 billion years ago than they are today. These supernovas are a major source of iron in the universe, the main component of Earth's core and an essential ingredient of the blood in our bodies.

Scientists have long been aware of the "universal expansion," the fact that galaxies are receding from one another. Observations using Type-Ia supernovas as beacons have shown that the expansion is accelerating, apparently under the influence of a mysterious "dark energy" -- the 2011 Nobel Prize in Physics will be awarded to three astronomers for this work. However, the nature of the supernovas themselves is poorly understood. This study improves our understanding by revealing the range of the ages of the stars that explode as Type-Ia supernovas. Eventually, this will enhance their usefulness for studying dark energy and the universal expansion, the researchers explain.

Natural Compound Helps Reverse Diabetes in Mice

Researchers (from left) Shin-ichiro Imai, MD, PhD, Jun Yoshino, MD, PhD, and Kathryn Mills showed that a natural compound, NMN, helps to treat symptoms of diabetes in mice. (Credit: Julia Evangelou Strait)

Science Daily  — Researchers at Washington University School of Medicine in St. Louis have restored normal blood sugar metabolism in diabetic mice using a compound the body makes naturally. The finding suggests that it may one day be possible for people to take the compound much like a daily vitamin as a way to treat or even prevent type 2 diabetes.

"After giving NMN, glucose tolerance goes completely back to normal in female diabetic mice," says Shin-ichiro Imai, MD, PhD, associate professor of developmental biology. "In males, we see a milder effect compared to females, but we still see an effect. These are really remarkable results. NMN improves diabetic symptoms, at least in mice."

This naturally occurring compound is called nicotinamide mononucleotide, or NMN, and it plays a vital role in how cells use energy.

The research appears online Oct. 4 in Cell Metabolism.

Imai says this discovery holds promise for people because the mechanisms that NMN influences are largely the same in mice and humans.

"But whether this mechanism is equally compromised in human patients with type 2 diabetes is something we have to check," Imai says. "We have plans to do this in the very near future."

All cells in the body make NMN in a chain of reactions leading to production of NAD, a vital molecule that harvests energy from nutrients and puts it into a form cells can use. Among other things, NAD activates a protein called SIRT1 that has been shown to promote healthy metabolism throughout the body, from the pancreas to the liver to muscle and fat tissue.

According to the study, aging and eating a high-fat diet reduce production of NMN, slowing the body's production of NAD and leading to abnormal metabolic conditions such as diabetes. NAD cannot be given to the mice directly because of toxic effects. But after administering NMN, levels of NAD rise and the diabetic mice show dramatically improved responses to glucose. In some cases, they return to normal.

"I'm very excited to see these results because the effect of NMN is much bigger than other known compounds or chemicals," says first author Jun Yoshino, MD, PhD, postdoctoral research associate. "Plus, the fact that the body naturally makes NMN is promising for translating these findings into humans."

Imai and his colleagues found that young, healthy mice on a high-fat diet developed diabetes in six months or less. In these mice, they found that NAD levels were reduced. But after administering NMN, levels of NAD increased and the female mice had normal results in glucose tolerance tests -- a measure of how well the body moves glucose from the blood to the organs and tissues for use. Glucose tolerance was also improved after male diabetic mice received NMN but did not quite return to normal. The researchers are interested in learning more about these differences between male and female mice.

"We don't have a clear answer, but we are speculating that sex hormones, such as estrogen, may be important downstream for NAD synthesis," Yoshino says.

In older mice, they observed that about 15 percent of healthy males fed a normal diet developed diabetes.

"When we injected these older diabetic mice with NMN, they had improved glucose tolerance, even after one injection," says Kathryn F. Mills, research lab supervisor and an equally contributing first author of the study. "We also injected older healthy mice and found that they weren't adversely affected. It's good to know that even if the mice are not diabetic, giving NMN is not going to hurt them."

Imai says few studies have examined normal mice that naturally develop diabetes as a simple result of aging because the experiments take so long. In an interesting twist, few elderly female mice developed diabetes at all. But after switching to a high fat diet, older female mice quickly developed severe diabetes.

"Again, when we injected these females with NMN, we came up with a completely normal glucose tolerance curve," Mills says. "We can also see that the NMN has completely reversed and normalized the levels of cholesterol, triglycerides and free fatty acids."

Though the mice received NMN by injection in this study, Imai's group is now conducting a long-term study of diabetic mice that get NMN dissolved in their drinking water. Imai calls this work a first step toward a possible "nutriceutical" that people could take almost like a vitamin to treat or even prevent type 2 diabetes.

"Once we can get a grade of NMN that humans can take, we would really like to launch a pilot human study," Imai says.