Scientists discover precise location of active sites on popular catalyst

August 13, 2015, Pacific Northwest National Laboratory
Scientists discover precise location of active sites on popular catalyst
Experimental work with vanadium oxide catalysts relied on sophisticated spectroscopy and chemical structure calculations to establish a relationship between specific sites on the catalysts and the degree of activity they bring out in a reaction. The work was published in the July 2, 2015, issue of ACS Catalysis and featured on the cover. Posted with permission from ACS Catalysis, July 2, 2015, 5(7). Credit: American Chemical Society

If you want to change a situation, it's often best to get to the heart of the matter. For chemists, this often means delving into the active sites of catalysts, which speed the reactions behind billions of dollars worth of chemicals and other products. Active sites are where the reaction actually happens. If active sites work slowly or fail quickly, the result is higher costs and lower production rates. To make better active sites, scientists need to see the sites. For the first time, a team led by researchers at Pacific Northwest National Laboratory saw the active sites on a well-known vanadium-based catalyst.

In addition to the PNNL staff, the team included experts from Washington State University, the University of Alabama, and the Dalian Institute of Chemical Physics, Chinese Academy of Sciences.

Fast. Stable. Efficient. These are the hallmarks of a good catalyst, one that can produce needed products without excessive costs or wastes. The results from this study could help researchers design such catalysts. How? By finding ways to create more active sites or protect existing sites from degrading during such reactions-or both.

In the experiments, the researchers dispersed or spread the catalyst on a support of to create a relatively large surface area with more reactive sites. They used a magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy technology at EMSL, the Department of Energy's Environmental Molecular Sciences Laboratory, to obtain detailed information about the structures of active species as they exist on the titanium dioxide support.

"Using an ultra-high magnetic field with fast spinning enabled the team to observe five types of surface vanadium oxide structures that exist when supported on the surfaces of titanium dioxide," said Dr. Jian Zhi Hu, a PNNL scientist and the team's lead.

The scientists correlated the various peaks observed in the NMR spectra with the catalysts' reactivity for an oxidation reaction that removes a hydrogen atom from methanol. Next, using computational methods, they predicted which peaks in the NMR spectra corresponded with the specific vanadium oxide geometries. In this way, the scientists determined which structures on the vanadium oxide surface do the best job of initiating and sustaining reactions.

The research team continues their efforts to study the structure of catalysts and their corresponding catalytic reactions. Their eventual aim is to gain a better understanding of the sites that most effectively bring about chemical reactions important for industrial uses.

Explore further: Catalysts caught in the act undergo radical rearrangements during reactions

More information: "Investigation of the Structure and Active Sites of TiO2 Nanorod Supported VOx Catalysts by High-Field and Fast-Spinning 51V MAS NMR." ACS Catalysis April 2015: 3945-3952. DOI: 10.1021/acscatal.5b00286.

Related Stories

Studying the chemistry as it happens in catalytic reactions

January 30, 2012

( -- While retaining their speed, catalysts have lost some of their secrets, thanks to a new probe built by scientists at Pacific Northwest National Laboratory to help clarify the steps catalysts take in promoting ...

Recommended for you

Targeting 'hidden pocket' for treatment of stroke and seizure

January 19, 2019

The ideal drug is one that only affects the exact cells and neurons it is designed to treat, without unwanted side effects. This concept is especially important when treating the delicate and complex human brain. Now, scientists ...

Using bacteria to create a water filter that kills bacteria

January 18, 2019

More than one in 10 people in the world lack basic drinking water access, and by 2025, half of the world's population will be living in water-stressed areas, which is why access to clean water is one of the National Academy ...

Hand-knitted molecules

January 18, 2019

Molecules are usually formed in reaction vessels or laboratory flasks. An Empa research team has now succeeded in producing molecules between two microscopically small, movable gold tips – in a sense as a "hand-knitted" ...

Artificially produced cells communicate with each other

January 18, 2019

Friedrich Simmel and Aurore Dupin, researchers at the Technical University of Munich (TUM), have for the first time created artificial cell assemblies that can communicate with each other. The cells, separated by fatty membranes, ...

This computer program makes pharma patents airtight

January 17, 2019

Routes to making life-saving medications and other pharmaceutical compounds are among the most carefully protected trade secrets in global industry. Building on recent work programming computers to identify synthetic pathways ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.