Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Green catalysts with Earth-abundant metals accelerate production of bio-based plastic

08.01.2019

How crystalline structure can affect the performance of MnO2 catalysts

Scientists at Tokyo Institute of Technology (Tokyo Tech) have developed and analyzed a novel catalyst for the oxidation of 5-hydroxymethyl furfural, which is crucial for generating new raw materials that replace the classic non-renewable ones used for making many plastics.


Replacing fossil based PET, known as raw material of soft drink bottles, with bio-based PEF largely contributes reduction of CO2 emissions.

Credit: Keigo Kamata of Tokyo Institute of Technology


Structures of (a) α-MnO2, (b) β-MnO2, (c) γ-MnO2, (d) δ-MnO2, and (e) λ-MnO2. Pink, green, and red spheres represent Mn, K, and O atoms, respectively. Of these, β-MnO2 is the most promising one as a catalyst for oxidation reactions because of the disposition and characteristics of its oxygen atoms.

Credit: Keigo Kamata of Tokyo Institute of Technology

It should be no surprise to most readers that finding an alternative to non-renewable natural resources is a key topic in current research.

Some of the raw materials required for manufacturing many of today's plastics involve non-renewable fossil resources, coal, and natural gas, and a lot of effort has been devoted to finding sustainable alternatives.

2,5-Furandicarboxylic acid (FDCA) is an attractive raw material that can be used to create polyethylene furanoate, which is a bio-polyester with many applications.

One way of making FDCA is through the oxidation of 5-hydroxymethyl furfural (HMF), a compound that can be synthesized from cellulose.

However, the necessary oxidation reactions require the presence of a catalyst, which helps in the intermediate steps of the reaction so that the final product can be achieved.

Many of the catalysts studied for use in the oxidation of HMF involve precious metals; this is clearly a drawback because these metals are not widely available. Other researchers have found out that manganese oxides combined with certain metals (such as iron and copper) can be used as catalysts.

Although this is a step in the right direction, an even greater finding has been reported by a team of scientists from Tokyo Tech: manganese dioxide (MnO2) can be used by itself as an effective catalyst if the crystals made with it have the appropriate structure.

The team, which includes Associate Professor Keigo Kamata and Professor Michikazu Hara, worked to determine which MnO2 crystal structure would have the best catalytic activity for making FDCA and why.

They inferred through computational analyses and the available theory that the structure of the crystals was crucial because of the steps involved in the oxidation of HMF. First, MnO2 transfers a certain amount of oxygen atoms to the substrate (HMF or other by-products) and becomes MnO2-δ.

Then, because the reaction is carried out under an oxygen atmosphere, MnO2-δ quickly oxidizes and becomes MnO2 again. The energy required for this process is related to the energy required for the formation of oxygen vacancies, which varies greatly with the crystal structure. In fact, the team calculated that active oxygen sites had a lower (and thus better) vacancy formation energy.

To verify this, they synthesized various types of MnO2 crystals, as shown in Figure, and then compared their performance through numerous analyses. Of these crystals, β-MnO2 was the most promising because of its active planar oxygen sites. Not only was its vacancy formation energy lower than that of other structures, but the material itself was proven to be very stable even after being used for oxidation reactions on HMF.

The team did not stop there, though, as they proposed a new synthesis method to yield highly pure β-MnO2 with a large surface area in order to improve the FDCA yield and accelerate the oxidation process even further. "The synthesis of high-surface-area β-MnO2 is a promising strategy for the highly efficient oxidation of HMF with MnO2 catalysts," states Kamata.

With the methodological approach taken by the team, the future development of MnO2 catalysts has been kick-started.

"Further functionalization of β-MnO2 will open up a new avenue for the development of highly efficient catalysts for the oxidation of various biomass-derived compounds," concludes Hara.

Researches such as this one ensure that renewable raw materials will be available to mankind to avoid all types of shortage crises.

Media Contact

Emiko Kawaguchi
media@jim.titech.ac.jp
81-357-342-975

http://www.titech.ac.jp/english/index.html 

Emiko Kawaguchi | EurekAlert!
Further information:
http://dx.doi.org/10.1021/jacs.8b09917

Further reports about: catalyst catalysts crystal structure crystals plastic raw materials

More articles from Life Sciences:

nachricht When predictions of theoretical chemists become reality
22.05.2020 | Technische Universität Dresden

nachricht From artificial meat to fine-tuning photosynthesis: Food System Innovation – and how to get there
20.05.2020 | Potsdam-Institut für Klimafolgenforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

Im Focus: NASA's Curiosity rover finds clues to chilly ancient Mars buried in rocks

By studying the chemical elements on Mars today -- including carbon and oxygen -- scientists can work backwards to piece together the history of a planet that once had the conditions necessary to support life.

Weaving this story, element by element, from roughly 140 million miles (225 million kilometers) away is a painstaking process. But scientists aren't the type...

Im Focus: Making quantum 'waves' in ultrathin materials

Study co-led by Berkeley Lab reveals how wavelike plasmons could power up a new class of sensing and photochemical technologies at the nanoscale

Wavelike, collective oscillations of electrons known as "plasmons" are very important for determining the optical and electronic properties of metals.

Im Focus: When proteins work together, but travel alone

Proteins, the microscopic “workhorses” that perform all the functions essential to life, are team players: in order to do their job, they often need to assemble into precise structures called protein complexes. These complexes, however, can be dynamic and short-lived, with proteins coming together but disbanding soon after.

In a new paper published in PNAS, researchers from the Max Planck Institute for Dynamics and Self-Organization, the University of Oxford, and Sorbonne...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

New gravitational-wave model can bring neutron stars into even sharper focus

22.05.2020 | Physics and Astronomy

A replaceable, more efficient filter for N95 masks

22.05.2020 | Materials Sciences

Capturing the coordinated dance between electrons and nuclei in a light-excited molecule

22.05.2020 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>