MMaterialsgateNEWS 2015/08/31

Soaking up carbon dioxide and turning it into valuable products

Berkeley Lab researchers double down on a good thing by incorporating catalysts into crystalline sponges

A molecular system that holds great promise for the capture and storage of carbon dioxide has been modified so that it now also holds great promise as a catalyst for converting captured carbon dioxide into valuable chemical products. Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have incorporated molecules of carbon dioxide reduction catalysts into the sponge-like crystals of covalent organic frameworks (COFs). This creates a molecular system that not only absorbs carbon dioxide, but also selectively reduces it to carbon monoxide, which serves as a primary building block for a wide range of chemical products including fuels, pharmaceuticals and plastics.

"There have been many attempts to develop homogeneous or heterogeneous catalysts for carbon dioxide, but the beauty of using COFs is that we can mix-and-match the best of both worlds, meaning we have molecular control by choice of catalysts plus the robust crystalline nature of the COF," says Christopher Chang, a chemist with Berkeley Lab's Chemical Sciences Division, and a co-leader of this study. "To date, such porous materials have mainly been used for carbon capture and separation, but in showing they can also be used for carbon dioxide catalysis, our results open up a huge range of potential applications in catalysis and energy."

Chang and Omar Yaghi, a chemist with Berkeley Lab's Materials Sciences Division who invented COFs, are the corresponding authors of a paper in Science that describes this research in detail. The paper is titled "Covalent organic frameworks comprising cobalt porphyrins for catalytic CO2 reduction in water." Lead authors are Song Lin, Christian Diercks and Yue-Biao Zhang. Other co-authors are Nikolay Kornienko, Eva Nichols, Yingbo Zhao, Aubrey Paris, Dohyung Kim and Peidong Yang.

Chang and Yaghi both hold appointments with the University of California (UC) Berkeley. Chang is also a Howard Hughes Medical Institute (HHMI) investigator. Yaghi is co-director of the Kavli Energy NanoScience Institute (Kavli-ENSI) at UC Berkeley.

The notoriety of carbon dioxide for its impact on the atmosphere and global climate change has overshadowed its value as an abundant, renewable, nontoxic and nonflammable source of carbon for the manufacturing of widely used chemical products. With the reduction of atmospheric carbon dioxide emissions in mind, Yaghi and his research group at the University of Michigan in 2005 designed and developed the first COFs as a means of separating carbon dioxide from flue gases. A COF is a porous three-dimensional crystal consisting of a tightly folded, compact framework that features an extraordinarily large internal surface area - a COF the size of a sugar cube were it to be opened and unfolded would blanket a football field. The sponge-like quality of a COF's vast internal surface area enables the system to absorb and store enormous quantities of targeted molecules, such as carbon dioxide.

Now, through another technique developed by Yaghi, called "reticular chemistry," which enables molecular systems to be "stitched" into netlike structures that are held together by strong chemical bonds, the Berkeley Lab researchers were able to embed the molecular backbone of COFs with a porphyrin catalyst, a ring-shaped organic molecule with a cobalt atom at its core. Porphyrins are electrical conductors that are especially proficient at transporting electrons to carbon dioxide.

"A key feature of COFs is the ability to modify chemically active sites at will with molecular-level control by tuning the building blocks constituting a COF's framework," Yaghi says. "This affords a significant advantage over other solid-state catalysts where tuning the catalytic properties with that level of rational design remains a major challenge. Because the porphyrin COFs are stable in water, they can operate in aqueous electrolyte with high selectivity over competing water reduction reactions, an essential requirement for working with flue gas emissions."

In performance tests, the porphyrin COFs displayed exceptionally high catalytic activity - a turnover number up to 290,000, meaning one porphyrin COF can reduce 290,000 molecules of carbon dioxide to carbon monoxide every second. This represents a 60-fold increase over the catalytic activity of molecular cobalt porphyrin catalyst and places porphyrin COFs among the fastest and most efficient catalysts of all known carbon dioxide reduction agents. Furthermore, the research team believes there's plenty of room for further improving porphyrin COF performances.

"We're now seeking to increase the number of electroactive cobalt centers and achieve lower over-potentials while maintaining high activity and selectivity for carbon dioxide reduction over proton reduction," Chang says. "In addition we are working towards expanding the types of value-added carbon products that can be made using COFs and related frameworks."

Source: DOE/Lawrence Berkeley National Laboratory – 27.08.2015.

Investigated and edited by:

Dr.-Ing. Christoph Konetschny, Inhaber und Gründer von Materialsgate
Büro für Material- und Technologieberatung
The investigation and editing of this document was performed with best care and attention.
For the accuracy, validity, availability and applicability of the given information, we take no liability.
Please discuss the suitability concerning your specific application with the experts of the named company or organization.

You want additional material or technology investigations concerning this subject?

Materialsgate is leading in material consulting and material investigation.
Feel free to use our established consulting services

MMore on this topic

The best material to keep carbon dioxide from natural gas wells from fouling the atmosphere may be a derivative of asphalt, according to Rice University scientists.

The Rice laboratory of chemist James Tour followed up on last year's discovery of a "green" carbon capture material for wellhead sequestration with the news that an even better compound could be made cheaply in a few steps from asphalt, the black, petroleum-based substance primarily used to build roads. The research appears in the American Chemical Society journal Applied Materials and Interfaces. The best version of several made by the Tour lab is a powder that holds 114 percent of its weight in carbon dioxide. Like last year's material, these new porous carbon materials capture carbon dioxide molecules at room temperature while letting the desired methane natural... more read more

Rice University scientists have discovered an environmentally friendly carbon-capture method that could be equally adept at drawing carbon dioxide emissions from industrial flue gases and natural gas wells.

The Rice lab of chemist Andrew Barron revealed in a proof-of-concept study that amine-rich compounds are highly effective at capturing the greenhouse gas when combined with carbon-60 molecules. The research is the subject of an open-access paper today in Nature’s online journal Scientific Reports. “We had two goals,” Barron said. “One was to make the compound 100 percent selective between carbon dioxide and methane at any pressure and temperature. The other was to reduce the high temperature needed by other amine solutions to get the carbon dioxide back out again. We’ve been successful on both counts.” Tests from one to 50 atmospheric pressures showed the Rice compound captured... more read more

More on this topic:

A new paradigm for the industrial chemical production has arisen over the last few years: the CO2 economy. According to this vision, CO2 is no longer seen as a waste product with dangerous environmental effects but increasingly as a feedstock for chemicals, fuels or polymers.

This vision has been gaining momentum and is now emerging from the research laboratories as a serious alternative path to securing the constant supply of carbon atoms the industrial chemistry sector will continue to need for their production cycles, even in a world where fossil resources are completely depleted. For the second year in a row, the conference "CO2 as chemical feedstock - a challenge for sustainable chemistry" will concentrate on this topic. It will be held on 7-9 October 2013 in the "Haus der Technik" in Essen, Germany and will be the biggest event on Carbon Capture and Utilization (CCU) in 2013. More than 300 participants from the leading industrial and... more read more

A novel porous material that has unique carbon dioxide retention properties has been developed through research led by The University of Nottingham.

The findings, published in the prestigious peer-reviewed journal Nature Materials, form part of ongoing efforts to develop new materials for gas storage applications and could have an impact in the advancement of new carbon capture products for reducing emissions from fossil fuel processes. It focuses on the metal organic framework NOTT-202a, which has a unique honeycomb-like structural arrangement and can be considered to represent an entirely new class of porous material. Most importantly, the material structure allows selective adsorption of carbon dioxide — while other gases such as nitrogen, methane and hydrogen can pass back through, the carbon dioxide remains trapped in the materials... more read more


Partner of the Week

Search in MaterialsgateNEWS

Books and products