Putting CO2 to a good use

One of the biggest culprits of climate change is an overabundance of carbon dioxide in the atmosphere.

As the world tries to find solutions to reverse the problem, scientists from Swansea University have found a way of using CO2 to create ethylene, a key chemical precursor. They have used ID03 to test their hypotheses.

Carbon dioxide is essential for the survival of animals and plants. However, people are the biggest producers of CO2 emissions. The extensive use of fossil fuels such as coal, oil, or natural gas has created an excess of CO2 in the atmosphere, leading to global warming. Considerable research focuses on capturing and storing harmful carbon dioxide emissions. But an alternative to expensive long-term storage is to use the captured CO2 as a resource to make useful materials.

>Read more on the European Synchrotron wesbite

New class of single atoms catalysts for carbon nanotubes

They exhibit outstanding electrochemical reduction of CO2 to CO.

Experiments using X-rays on two beamlines at the Australian Synchrotron have helped characterise a new class of single atom catalysts (SACs) supported on carbon nanotubes that exhibit outstanding electrochemical reduction of CO2 to CO. A weight loading of 20 wt% for the new class, nickel single atom nitrogen doped carbon nanotubes (NiSA-N-CNTs), is believed to be the highest metal loading for SACs reported to date.

Single atoms of nickel, cobalt and iron were supported on nitrogen doped carbon nanotubes via a one-pot pyrolysis method and compared in the study.

A large international collaboration, led by Prof San Ping Jiang, Deputy Director of the Fuels and Energy Technology Institute at the Curtin University of Technology and associates from the Department of Chemical Engineering, have developed a new synthesis and development process for nitrogen-doped carbon nanotubes with a nickel ligand that demonstrate high catalytic activity.

The study was published in Advanced Materials and featured on the inside cover of the publication.

Dr Bernt Johannessen, instrument scientist on the X-ray absorption spectroscopy (XAS) beamline at the Australian Synchrotron was a co-author on the paper, which also included lead investigators from Curtin University of Technology and collaborators at the University of Western Australia, Institute of Metal Research (China), Oak Ridge National Laboratory (US), University of the Sunshine Coast, University of Queensland, Tsinghua University (China) and King Abdulaziz University (Saudi Arabia). Technical support and advice on the soft X-ray spectroscopy experiments was provided by Australian Synchrotron instrument scientist Dr Bruce Cowie.

>Read more on the Australian Synchrotron website

Image: extract of the cover of Advanced Materials.

Edges and corners increase efficiency of catalytic converters

X-rays reveal oxide islands on noble metal nanoparticles

Catalytic converters for cleaning exhaust emissions are more efficient when they use nanoparticles with many edges. This is one of the findings of a study carried out at DESY’s X-ray source PETRA III. A team of scientists from the DESY NanoLab watched live as noxious carbon monoxide (CO) was converted into common carbon dioxide (CO2) on the surface of noble metal nanoparticles like those used in catalytic converters of cars. The scientists are presenting their findings in the journal Physical Review Letters. Their results suggest that having a large number of edges increases the efficiency of catalytic reactions, as the different facets of the nanoparticles are often covered by growing islands of a nano oxide, finally rendering these facets inactive. At the edges, the oxide islands cannot connect, leaving active sites for the catalytic reaction and an efficient oxygen supply.
Catalytic converters usually use nanoparticles because these have a far greater surface area for a given amount of the material, on which the catalytic reaction can take place. For the study presented here, the scientists at DESY’s NanoLab grew platinum-rhodium nanoparticles on a substrate in such a way that virtually all the particles were aligned in the same direction and had the same shape of truncated octahedrons (octahedrons resemble double pyramids). The scientists then studied the catalytic properties of this sample under the typical working conditions of an automotive catalytic converter, with different gaseous compositions in a reaction chamber that was exposed to intense X-rays from PETRA III on the P09 beamline.

>Read more on the PETRA III at DESY website

Image: With increasing oxygen (red) concentration, an oxide sandwich forms on the surface of the metallic nanoparticles, inhibiting the desired reaction of carbon monoxide to carbon dioxide. At the edges, however, the oxide sandwich brakes up, leaving free active sites for catalysis. The more edges the nanoparticles posses, the more efficient will the catalytic converter work.
Credit: DESY, Lucid Berlin

Cleaner diesel emissions

More effective control of diesel nitrogen oxides through dosed addition of ammonia

In diesel engines, the burning of the fuel releases nitrogen oxides (NOx), which are harmful to human health. The automobile industry therefore developed a technique that reduces these emissions: Gaseous ammonia is added to the exhaust and, prompted by a catalyst, reacts with the nitrogen oxides to produce harmless nitrogen and water. At low temperatures, however, this process does not yet work optimally. Now, for the first time, scientists at the Paul Scherrer Institute PSI have found a remedy which is based on observations at the molecular level: The precise amount of added ammonia needs to be varied depending on the temperature. With this knowledge, manufacturers can improve the effectiveness of their catalytic converters for diesel vehicles. The researchers have now published their findings in the journal Nature Catalysis.

>Read more on the Paul Scherrer Institute website

Image: At the X-ray beam line: Davide Ferri (left) and Maarten Nachtegaal at the SLS experimental station where they studied diesel catalysis.
Photo: Paul Scherrer Institute/Markus Fischer

Converting CO2 into usable energy

Scientists show that single nickel atoms are an efficient, cost-effective catalyst for converting carbon dioxide into useful chemicals.

Imagine if carbon dioxide (CO2) could easily be converted into usable energy. Every time you breathe or drive a motor vehicle, you would produce a key ingredient for generating fuels. Like photosynthesis in plants, we could turn CO2 into molecules that are essential for day-to-day life. Now, scientists are one step closer.

Researchers at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory are part of a scientific collaboration that has identified a new electrocatalyst that efficiently converts CO2 to carbon monoxide (CO), a highly energetic molecule. Their findings were published on Feb. 1 in Energy & Environmental Science.

“There are many ways to use CO,” said Eli Stavitski, a scientist at Brookhaven and an author on the paper. “You can react it with water to produce energy-rich hydrogen gas, or with hydrogen to produce useful chemicals, such as hydrocarbons or alcohols. If there were a sustainable, cost-efficient route to transform CO2 to CO, it would benefit society greatly.”

>Read more on the NSLS-II website

Image: Brookhaven scientists are pictured at NSLS-II beamline 8-ID, where they used ultra-bright x-ray light to “see” the chemical complexity of a new catalytic material. Pictured from left to right are Klaus Attenkofer, Dong Su, Sooyeon Hwang, and Eli Stavitski.

 

Atomic Flaws Create Surprising, High-Efficiency UV LED Materials

Subtle surface defects increase UV light emission in greener, more cost-effective LED and catalyst materials

Light-emitting diodes (LEDs) traditionally demand atomic perfection to optimize efficiency. On the nanoscale, where structures span just billionths of a meter, defects should be avoided at all costs—until now.

A team of scientists from the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Stony Brook University has discovered that subtle imperfections can dramatically increase the efficiency and ultraviolet (UV) light output of certain LED materials.

“The results are surprising and completely counterintuitive,” said Brookhaven Lab scientist Mingzhao Liu, the senior author on the study. “These almost imperceptible flaws, which turned out to be missing oxygen in the surface of zinc oxide nanowires, actually enhance performance. This revelation may inspire new nanomaterial designs far beyond LEDs that would otherwise have been reflexively dismissed.”

>Read more on the NSLS-II website

Image: The research team, front to back and left to right: Danhua Yan, Mingzhao Liu, Klaus Attenkoffer, Jiajie Cen, Dario Stacciola, Wenrui Zhang, Jerzy Sadowski, Eli Stavitski.

 

Structure and Catalytic Activity of Copper Nanoparticles

Research investigates the addition of ceria on the activity of catalysts for the water-gas shift reaction

Catalysts are substances that promote and accelerate chemical reactions without being consumed during the process and are widely used in industrial processes to produce various chemicals.

Catalysts based on copper nanoparticles dispersed in an oxide support benefit various reactions, such as the synthesis of methanol, the alcohol dehydrogenation, or the water gas shift (WGS) reaction which is one of the main processes for hydrogen production on an industrial scale. In this reaction, carbon monoxide reacts with water to produce carbon dioxide CO2 and hydrogen gas H2.

>Read more on the LNLS website

Figure 1: Correlation between the bond length of CuO and the catalyst turnover frequency (TOF) for the catalysts analyzed under WGS conditions with different proportions of copper and ceria.

 

2017’s Top-10 Discoveries and Scientific Achievements

Each year we compile a list of the biggest advances made by scientists, engineers, and those who support their work at the U.S. Department of Energy’s Brookhaven National Laboratory. From unraveling new details of the particle soup that filled the early universe to designing improvements for batteries, x-ray imaging, and even glass, this year’s selections span a spectrum of size scales and fields of science. Read on for a recap of what our passion for discovery has uncovered this year.  (…)

4. Low-Temperature Hydrogen Catalyst

Brookhaven chemists conducted essential studies to decipher the details of a new low-temperature catalyst for producing high-purity hydrogen gas. Developed by collaborators at Peking University, the catalyst operates at low temperature and pressure, and could be particularly useful in fuel-cell-powered cars. The Brookhaven team analyzed the catalyst as it was operating under industrial conditions using x-ray diffraction at the National Synchrotron Light Source (NSLS). These operando experiments revealed how the configuration of atoms changed under different operating conditions, including at different temperatures. The team then used those structural details to develop models and a theoretical framework to explain why the catalyst works so well, using computational resources at Brookhaven’s Center for Functional Nanomaterials (CFN).

 >Read more on the NSLS-II website

 

New Catalyst Gives Artificial Photosynthesis a Big Boost

Inspired by plants: Inorganic catalyst converts electrical energy to chemical energy at 64% efficiency

Researchers have created a new catalyst that brings them one step closer to artificial photosynthesis — a system that would use renewable energy to convert carbon dioxide (CO2) into stored chemical energy.

As in plants, their system consists of two linked chemical reactions: one that splits water (H2O) into protons and oxygen gas, and another that converts CO2 into carbon monoxide (CO). The CO can then be converted into hydrocarbon fuels through an established industrial process. The system would allow both the capture of carbon emissions and the storage of energy from solar or wind power.

Yufeng Liang and David Prendergast – scientists at the Molecular Foundry, a nanoscale research facility at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) – performed theoretical modeling work used to interpret X-ray spectroscopy measurements made in the study, published Nov. 20 in Nature Chemistry. This work was done in support of a project originally proposed by the University of Toronto team to the Molecular Foundry, a DOE Office of Science User Facility.

 

>Read more on the ALS website

Image: Phil De Luna of University of Toronto is one of the lead authors of a new study that reports a low-cost, highly efficient catalyst for chemical conversion of water into oxygen. The catalyst is part of an artificial photosynthesis system in development at the University of Toronto.
Credit: Tyler Irving/University of Toronto

Making the world go round

A look into the structure of a prominent heterogeneous catalyst

Fluid catalytic cracking, a century old chemical conversion process utilizing porous composites of zeolite and clay, up to this day provides the majority of the world’s gasoline. Owing to harsh reaction environments and feedstock impurities the employed catalysts deactivate, necessitating their continuous fractional replacement with major refineries requiring up to 40 tons of fresh catalyst in total on a daily basis. Using a combination of ptychographic, x-ray diffraction and -fluorescence tomography researchers from PSI and ETH elucidated the structural changes behind catalyst deactivation.

Read more on the PSI website.

Image: Cropped – Ptychographic image reconstructions. a Volume reconstructions of FCC1, FCC2, and FCC3. Orthoslices through the retrieved electron density maps are shown in b–d, respectively. Presented are bottom up (z–x) and orthogonal views (y–z, y–x). Cutting planes are represented by dotted lines. Shown in e–g are enlarged versions of selected areas. Common to all subfigures is the linear grey scale for the electron density. Selected diffusion highways (-) are highlighted in pink, hydrocarbon deposits by a red triangle, and the ASA shell by a blue cross. Voxel size is about (20 nm)3. Scale bars are 5 µm