Converting CO2 to Valuable Resources (ethanol and propanol) with the help of Nanoparticles


Ruhr CO2 1 2019_09_27_schuhmann_jacs_tk_01

An international research team has used nanoparticles to convert carbon dioxide into valuable raw materials. The team transferred this mechanism to metallic nanoparticles, also known as nanozymes. The chemists used carbon dioxide to produce ethanol and propanol, which are common raw materials for the chemical industry.

An international research team has used nanoparticles to convert carbon dioxide into valuable raw materials. Scientists at Ruhr-Universität Bochum in Germany and the University of New South Wales in Australia have adopted the principle from enzymes that produce complex molecules in multi-step reactions. The team transferred this mechanism to metallic nanoparticles, also known as nanozymes. The chemists used carbon dioxide to produce ethanol and propanol, which are common raw materials for the chemical industry.

The team led by Professor Wolfgang Schuhmann from the Center for Electrochemistry in Bochum and Professor Corina Andronescu from the University of Duisburg-Essen, together with the Australian team led by Professor Justin Gooding and Professor Richard Tilley, reported in the Journal of the American Chemical Society on 25 August 2019.

“Transferring the cascade reactions of the enzymes to catalytically active nanoparticles could be a decisive step in the design of catalysts,” says Wolfgang Schuhmann.

Ruhr U CO2 2 nanoparticles

Credit: CC0 Public Domain

Particle with two active centres

Enzymes have different active centres for cascade reactions, which are specialised in certain reaction steps. For example, a single enzyme can produce a complex product from a relatively simple starting material. In order to imitate this concept, the researchers synthesised a particle with a silver core surrounded by a porous layer of copper. The silver core serves as the first active centre, the copper layer as the second. Intermediate products formed at the silver core then react in the copper layer to form more complex molecules, which ultimately leave the particle.

In the present work, the German-Australian team showed that the electrochemical reduction of carbon dioxide can take place with the help of the nanozymes. Several reaction steps on the silver core and copper shell transform the starting material into ethanol or propanol.

“There are also other nanoparticles that can produce these products from CO2 without the cascade principle,” says Wolfgang Schuhmann. “However, they require considerably more energy.”

The researchers now want to further develop the concept of the cascade reaction in nanoparticles in order to be able to selectively produce even more valuable products such as ethylene or butanol.

Story Source:

Materials provided by Ruhr-University BochumNote: Content may be edited for style and length.


Journal Reference:

  1. Peter B. O’Mara, Patrick Wilde, Tania M. Benedetti, Corina Andronescu, Soshan Cheong, J. Justin Gooding, Richard D. Tilley, Wolfgang Schuhmann. Cascade Reactions in Nanozymes: Spatially Separated Active Sites inside Ag-Core–Porous-Cu-Shell Nanoparticles for Multistep Carbon Dioxide Reduction to Higher Organic MoleculesJournal of the American Chemical Society, 2019; 141 (36): 14093 DOI: 10.1021/jacs.9b07310

University of Waterloo Researchers develop New Powder that is 2X More Effective for ‘Carbon Capture’ – Could Drastically Reduce CO2 Emissions – Also Applications for Energy Storage and Water Filtration


Carbon capture 1 novelfunctioNovel functionalized nanomaterials for CO2 capture. Credit: Copyright Royal Society of Chemistry (RSC). Polshettiwar et al. Chemical Science

Scientists at the University of Waterloo have created a powder that can capture CO2 from factories and power plants.

The powder, created in the lab of Zhongwei Chen, a chemical engineering professor at Waterloo, can filter and remove CO2 at facilities powered by fossil fuels before it is released into the atmosphere and is twice as efficient as conventional methods.

Chen said the new process to manipulate the size and concentration of pores could also be used to produce optimized carbon powders for applications including water filtration and energy storage, the other main strand of research in his lab.

“This will be more and more important in the future,” said Chen, “We have to find ways to deal with all the CO2 produced by burning fossil fuels.”

CO2 molecules stick to the surface of carbon when they come in contact with it, a process known as adsorption. Since it is abundant, inexpensive and environmentally friendly, that makes carbon an excellent material for CO2 capture. The researchers, who collaborated with colleagues at several universities in China, set out to improve adsorption performance by manipulating the size and concentration of pores in carbon materials.

The technique they developed uses heat and salt to extract a black carbon powder from plant matter. Carbon spheres that make up the powder have many, many pores and the vast majority of them are less than one-millionth of a metre in diameter.Carbon Capture 2 16-MS-2494-EE-Science-Cover_v6-

“The porosity of this material is extremely high,” said Chen, who holds a Tier 1 Canada Research Chair in advanced materials for clean energy. “And because of their size, these pores can capture CO2 very efficiently. The performance is almost doubled.”

Once saturated with carbon dioxide at large point sources such as fossil fuel power plants, the powder would be transported to storage sites and buried in underground geological formations to prevent CO2 release into the atmosphere.

A paper on the CO2 capture work, In-situ ion-activated carbon nanospheres with tunable ultra-microporosity for superior CO2 capture, appears in the journal Carbon.

Professor Chen can be reached at zhwchen@uwaterloo.ca or 519-888-4567 ext. 38664.

Read More About Recent CO2 Capture Technologies

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Penn State U. – New ‘Flow-Cell’ Battery Recharged with Carbon Dioxide – Capturing CO2 Emissions for an Untapped Source of Energy


co2flowcell
The pH-gradient flow cell has two channels: one containing an aqueous solution sparged with carbon dioxide (low pH) and the other containing an aqueous solution sparged with ambient air (high pH). The pH gradient causes ions to flow across …more

Researchers have developed a type of rechargeable battery called a flow cell that can be recharged with a water-based solution containing dissolved carbon dioxide (CO2) emitted from fossil fuel power plants. The device works by taking advantage of the CO2 concentration difference between CO2 emissions and ambient air, which can ultimately be used to generate electricity.

The new flow cell produces an average power density of 0.82 W/m2, which is almost 200 times higher than values obtained using previous similar methods. Although it is not yet clear whether the process could be economically viable on a large scale, the early results appear promising and could be further improved with future research.

The scientists, Taeyong Kim, Bruce E. Logan, and Christopher A. Gorski at The Pennsylvania State University, have published a paper on the new method of CO2-to-electricity conversion in a recent issue of Environmental Science & Technology Letters.

“This work offers an alternative, simpler means to capturing energy from CO2 emissions compared to existing technologies that require expensive catalyst materials and very high temperatures to convert CO2 into useful fuels,” said Gorski.

While the contrast of gray-white smoke against a blue sky illustrates the adverse environmental impact of burning , the large difference in CO2 concentration between the two gases is also what provides an untapped energy source for generating electricity.fossil-fuels-co2-to-green-images

In order to harness the potential energy in this concentration difference, the researchers first dissolved CO2 gas and in separate containers of an aqueous solution, in a process called sparging. At the end of this process, the CO2-sparged solution forms bicarbonate ions, which give it a lower pH of 7.7 compared to the air-sparged solution, which has a pH of 9.4.

After sparging, the researchers injected each solution into one of two channels in a flow cell, creating a pH gradient in the cell. The flow cell has electrodes on opposite sides of the two channels, along with a semi-porous membrane between the two channels that prevents instant mixing while still allowing ions to pass through. Due to the pH difference between the two solutions, various ions pass through the membrane, creating a voltage difference between the two electrodes and causing electrons to flow along a wire connecting the electrodes.

After the flow cell is discharged, it can be recharged again by switching the channels that the solutions flow through. By switching the solution that flows over each electrode, the charging mechanism is reversed so that the electrons flow in the opposite direction. Tests showed that the cell maintains its performance over 50 cycles of alternating solutions.

The results also showed that, the higher the pH difference between the two channels, the higher the average power density. Although the pH-gradient flow cell achieves a power density that is high compared to similar cells that convert waste CO2 to electricity, it is still much lower than the power densities of fuel cell systems that combine CO2 with other fuels, such as H2.

However, the new flow cell has certain advantages over these other devices, such as its use of inexpensive materials and room-temperature operation. These features make the flow cell attractive for practical applications at existing .

“A system containing numerous identical flow cells would be installed at power plants that combust fossil fuels,” Gorski said. “The flue gas emitted from fossil fuel combustion would need to be pre-cooled, then bubbled through a reservoir of water that can be pumped through the flow cells.”

In the future, the researchers plan to further improve the flow cell performance.

“We are currently looking to see how the solution conditions can be optimized to maximize the amount of energy produced,” Gorski said. “We are also investigating if we can dissolve chemicals in the water that exhibit pH-dependent redox properties, thus allowing us to increase the amount of energy that can be recovered. The latter approach would be analogous to a flow battery, which reduces and oxidizes dissolved chemicals in aqueous solutions, except we are causing them to be reduced and oxidized here by changing the solution pH with CO2.”

Explore further: Chemists present an innovative redox-flow battery based on organic polymers and water

More information: Taeyoung Kim et al. “A pH-Gradient Flow Cell for Converting Waste CO2 into Electricity.” Environmental Science & Technology Letters. DOI: 10.1021/acs.estlett.6b00467