Tag: catalyst

Conversion of carbon dioxide into raw materials more effective with gold

Conversion of carbon dioxide into raw materials more effective with gold

Carbon dioxide, emitted mainly by combustion of fossil fuels, is harmful to the climate and the main reason for increased global warming. Diverting carbon dioxide into hydrogen carriers or chemicals such as methanol, a valuable raw material and energy carrier, is thus highly desired. Supported metal nanoparticle heterogeneous catalysts such as copper on zinc oxide is used for the catalytic conversion of carbon dioxide to methanol. Researchers have now discovered that it is possible to avoid by-products and at the same time make the process more sustainable by adding a small amount of gold to the catalyst.

Carbon dioxide can be converted into methanol and water by reaction with hydrogen. The reaction is only possible in the presence of a catalytic material such as Au or Cu nanoparticles supported on zinc oxide. The chemical reaction will then take place on the particle surfaces. In a recent study, a research team from Germany, Japan and Sweden have shown that modifying the typical ZnO-supported Cu nanoparticles by a small amount of gold (< 10 weight percent) makes the reaction more selective.

Read more on MAX IV website

Towards greener chemical processes with a new catalyst for ethylene hydroformylation

Towards greener chemical processes with a new catalyst for ethylene hydroformylation

A research led by ITQ (UPV-CSIC) has demonstrated the possibility to replace molecular catalysts in solution for all-solid catalysts based on isolated metal atoms for selective gas-phase ethylene hydroformylation, an important industrial chemical reaction. The discovery paves the way for greener chemical processes, with greater energy efficiency and lower carbon footprint, for the valorization of unconventional raw materials, alternative to crude oil. To test the designed catalyst, synchrotron light techniques have been used, among others, at the ALBA Synchrotron.

The hydroformylation of ethylene is a chemical process of remarkable industrial significance. In particular, this chemical reaction entails the net addition of a formyl group (-CHO carbon, hydrogen and oxygen) and a hydrogen atom to the ethylene carbon-carbon double bond. This process enables valorizing raw materials such as refinery off-gases as well as unconventional feedstocks such as shale-gas (a kind of natural gas) into oxygenated platform chemicals. Moreover, hydroformylation is also considered a reactive separation alternative to current cryogenic distillations, which are applied to recover ethylene, a valuable commodity chemical, from mixtures with less valuable gases such as ethane. Such cryogenic distillation separations count among the most energy demanding operations in the chemical industry and are therefore associated to high carbon footprints.

Catalysts are materials that are central to steering essentially all chemical transformations of the current chemical industry. A major class of industrially applied catalysts consists of molecular organometallic compounds that operate in a liquid solvent. These catalysts have proven to be highly active and exceedingly selective for a wide range of important transformations. However, they also face significant challenges. First, their limited thermal and chemical stability, which shortens their functional lifetime. On the other hand, the technical complexity associated with their recovery from liquid mixtures with products and solvents of the process, to prevent losses of the precious metals these catalysts are typically made of.

Now, scientists from the Instituto de Tecnología Química (ITQ, UPV-CSIC), the ALBA Synchrotron, the Institute for Nanoscience & Materials of Aragón (INMA, CSIC-UZ) and the Karlsruhe Institute for Technology have designed a new catalyst for selective gas-phase ethylene hydroformylation. Their research shows that a material bearing isolated atoms of rhodium (Rh) stabilized within the surface of stannic oxide (SnO2) is an all-inorganic solid catalyst which delivers an exceptional performance for the gas-phase hydroformylation of ethylene, in par with those thus far exclusive for conventional molecular catalysts in liquid media.

Read more on the ALBA website

Image: From left to right: Giovanni Agostini (former beamline responsible at NOTOS, ALBA), Gonzalo Prieto (ITQ), Juan José Cortés (ITQ), Wilson Henao (ITQ), Carlos Escudero (beamline scientist at NOTOS, ALBA) and Carlo Marini (beamline responsible of NOTOS, ALBA).

New catalyst could cut pollution from millions of engines

New catalyst could cut pollution from millions of engines

Researchers demonstrate a way to remove the potent greenhouse gas from the exhaust of engines that burn natural gas.

Individual palladium atoms attached to the surface of a catalyst can remove 90% of unburned methane from natural-gas engine exhaust at low temperatures, scientists reported today in the journal Nature Catalysis. 

While more research needs to be done, they said, the advance in single atom catalysis has the potential to lower exhaust emissions of methane, one of the worst greenhouse gases, which traps heat at about 25 times the rate of carbon dioxide. 

Researchers from the Department of Energy’s SLAC National Accelerator Laboratory and Washington State University showed that the catalyst removed methane from engine exhaust at both the lower temperatures where engines start up ­­­and the higher temperatures where they operate most efficiently, but where catalysts often break down. 

“It’s almost a self-modulating process which miraculously overcomes the challenges that people have been fighting – low temperature inactivity and high temperature instability,” said Yong Wang, Regents Professor in WSU’s Gene and Linda Voiland School of Chemical Engineering and Bioengineering and one of four lead authors on the paper. 

A growing source of methane pollution 

Engines that run on natural gas power 30 million to 40 million vehicles worldwide and are popular in Europe and Asia. The natural gas industry also uses them to run compressors that pump gas to people’s homes. They are generally considered cleaner than gasoline or diesel engines, creating less carbon and particulate pollution.

However, when natural-gas engines start up, they emit unburnt, heat-trapping methane because their catalytic converters don’t work well at low temperatures. Today’s catalysts for methane removal are either inefficient at lower exhaust temperatures or they severely degrade at higher temperatures. 

“There’s a big drive towards using natural gas, but when you use it for combustion engines, there will always be unburnt natural gas from the exhaust, and you have to find a way to remove that. If not, you cause more severe global warming,” said co-author Frank Abild-Pedersen, a SLAC staff scientist and co-director of the lab’s SUNCAT Center for Interface Science and Catalysis, which is run jointly with Stanford University. “If you can remove 90% of the methane from the exhaust and keep the reaction stable, that’s tremendous.”

A catalyst with single atoms of the chemically active metal dispersed on a support also uses every atom of the expensive and precious metal, Wang added. 

“If you can make them more reactive,” he said, “that’s the icing on the cake.”

Unexpected help from a fellow pollutant 

In their work, the researchers showed that their catalyst made from single palladium atoms on a cerium oxide support efficiently removed methane from engine exhaust, even when the engine was just starting. 

They also found that trace amounts of carbon monoxide that are always present in engine exhaust played a key role in dynamically forming active sites for the reaction at room temperature. The carbon monoxide helped the single atoms of palladium migrate to form two- or three-atom clusters that efficiently break apart the methane molecules at low temperatures. 

Then, as the exhaust temperatures rose, the clusters broke up into single atoms and redispersed, so that the catalyst was thermally stable. This reversible process enabled the catalyst to work effectively and used every palladium atom the entire time the engine was running – including when it started cold.

Read more on SLAC website

Understanding How the Structure of Boron Oxynitride Affects its Photocatalytic Properties

Understanding How the Structure of Boron Oxynitride Affects its Photocatalytic Properties

Synchrotron studies show that tuning the synthesis of boron oxynitride can improve its performance as a photocatalyst and semiconductor

Carbon dioxide (CO2) is often in the news these days. As a greenhouse gas, released during the combustion of fossil fuels, it is fuelling climate change, and reducing our CO2 emissions is critical to a sustainable future. CO2 is also a by-product of many industrial processes, including the production of ammonia used for fertilisers. On the other hand, many industries need a regular supply of CO2, and shortages have caused problems in recent years. It makes sense, therefore, to find ways to recycle some of the waste CO2 we produce into useful products. However, CO2 conversion reactions are energy-intensive, and new catalysts are needed to make the reactions more efficient. Photocatalysts absorb light energy, creating a charge separation that can then drive a chemical reaction. A team of researchers from Imperial College London are researching CO2 conversion using photocatalysis. In work recently published in Chemistry of Materials, they investigated how oxygen doping affects the photocatalytic and optoelectronic properties of boron nitride. Their results provide valuable insights into the photochemistry of boron oxynitride (BNO) at the fundamental level.

By clarifying the importance of paramagnetism in BNO semiconductors and providing fundamental insight into their photophysics, this study paves the way to tailoring its properties for CO2 conversion photocatalysis. The group has also recently used a similar methodology to investigate phosphorus doping of boron nitride, which they will explore in a future publication. 

Read more on the Diamond Light Source website

Image: Combined experimental (EPR, NEXAFS) + computational study (DFT)

Credit: Image via Chem. Mater. 2023, 35, 5, 1858-1867

Synthesised a new catalyst with key properties to solve environmental issues

Synthesised a new catalyst with key properties to solve environmental issues

A research led by the ITQ-CSIC-UPV has discovered a new catalyst enabling hydrogenation of carbon dioxide to methane with advantages not seen until now. This new catalyst, whose structure and mechanism have been understood by synergistically exploiting different ALBA Synchrotron techniques, can be used for methane (natural syngas) production, that is considered as a promising energy carrier for hydrogen storage.

Linear economy has proven to be unsustainable in the long run due to its ineffective use of natural resources that leads to a huge amount of greenhouse gas emissions and waste generation. An alternative model, the so-called circular economy is based on an efficient production cycle that focuses on minimising waste and better recycling and seems to be key to find solutions for the climate crisis. One process that can be essential in this challenge is carbon dioxide (CO2) sequestration and usage, that is, transform atmospheric or produced carbon dioxide into energy carriers or platform molecules of the chemical industry.

An international collaboration between the Instituto de Tecnología Química – a join research center between Consejo Superior de Investigaciones Científicas and Universitat Politècnica de València (ITQ-CSIC-UPV), SOLEIL Synchrotron, Universidad de Cádiz, and ALBA Synchrotron permitted to synthesize a new catalyst able to hydrogenate carbon dioxide to methane with significant improvements in comparison to existing analogues. Its main advantage is that it possesses a much higher activity and so the reaction temperature can be lowered from usual 270-400ºC to only 180ºC, with an excellent long-term stability. Furthermore, this catalyst is able to operate under intermittent power supply conditions, which couples very well with electricity production systems based on renewable energies. Moreover, its synthetic procedure itself is ecofriendly, making it an even greater option in environmental issues.

This new catalyst can be used for methane (natural syngas) production, that is considered as a promising energy carrier for hydrogen storage.

The new solid catalyst was designed and synthesized in the ITQ (CSIC-UPV) by a mild, green hydrothermal synthesis procedure resulting in a material that contains interstitial carbon atoms doped in the ruthenium (Ru) oxide crystal lattice, enabling the stabilization of Ru cations in a low oxidation state with the formation of a none yet reported ruthenium oxy-carbonate phase.

Read more on ALBA website

New catalyst twice as selective, could make chemical production cleaner and cheaper

New catalyst twice as selective, could make chemical production cleaner and cheaper

An estimated 18 million tonnes of acetic acid are produced annually around the world for industrial applications like making paints, adhesives and coatings. Now, researchers from the University of Toronto (U of T) have demonstrated a new electrically powered catalyst that is twice as efficient as baseline materials at producing acetic acid. Their research has the added bonus of having a much smaller carbon footprint.

Catalysts are used to help convert raw materials into usable products, but the raw materials used to make acetic acid today are fossil fuel-based, meaning production can have negative environmental impacts. Here, the only inputs are CO2-derived CO, water and renewable electricity.

“In this project, I identified a strategy to design catalysts that might be extremely selective to a single chemical, meaning they produce more of the chemical you want, in this case acetic acid, and much less of the by-product chemicals you don’t want,” says Joshua Wicks, a doctoral student in Professor Edward Sargent’s research group at UofT.

“In our lab, we are very interested in the decarbonization of chemicals production and we’re always searching for promising opportunities to apply electrochemistry in this hard-to-decarbonize sector of the economy.”

Read more on the Canadian Light Source website

Image : Panos Papangelakis setting up in-situ XAS experiments

Green hydrogen: Nanostructured nickel silicide shines as a catalyst

Green hydrogen: Nanostructured nickel silicide shines as a catalyst

Electrical energy from wind or sun can be stored as chemical energy in hydrogen, an excellent fuel and energy carrier. The prerequisite for this, however, is efficient electrolysis of water with inexpensive catalysts. For the oxygen evolution reaction at the anode, nanostructured nickel silicide now promises a significant increase in efficiency. This was demonstrated by a group from the HZB, Technical University of Berlin and the Freie Universität Berlin as part of the CatLab research platform with measurements among others at BESSY II.

Electrolysis might be a familiar concept from chemistry lessons in school: Two electrodes are immersed in water and put under voltage. This voltage causes water molecules to break down into their components, and gas bubbles rise at the electrodes: Oxygen gas forms at the anode, while hydrogen bubbles form at the cathode. Electrolysis could produce hydrogen in a CO2-neutral way – as long as the required electricity is generated by fossil free energy forms such as sun or wind.

The only problem is that these reactions are not very efficient and extremely slow. To speed up the reactions, catalysts are used, based on precious and rare metals such as platinum, ruthenium or iridium. For large-scale use, however, such catalysts must consist of widely available and very cheap elements.

Read more on the HZB website

Image: Crystalline nickel silicide (left) is chemically transformed into nanostructured material with excellent catalytic properties for the electrolytic splitting of water and the production of valuable nitrile compounds. 

Credit: © P. Menezes /HZB/TU Berlin

I am doing science that is more important than my sleep!

I am doing science that is more important than my sleep!

NSLS-II #LightSourceSelfie

Dan Olds is an associate physicist at Brookhaven National Laboratory where he works as a beamline scientist at NSLS-II. Dan’s research involves combining artificial intelligence and machine learning to perform real-time analysis on streaming data while beamline experiments are being performed. Often these new AI driven methods are critical to success during in situ studies of materials. These include next generational battery components, accident safe nuclear fuels, catalytic materials and other emerging technologies that will help us develop clean energy solutions to fight climate change.

Dan’s #LightSourceSelfie delves into what attracted him to this area of research, the inspiration he gets from helping users on the beamline and the addictive excitement that comes from doing science at 3am.

Promising new extra-large pore zeolite

Promising new extra-large pore zeolite

An international research team, led in Spain by CSIC scientist Miguel A. Camblor, has discovered a stable aluminosilicate zeolite with a three dimensional system of interconnected extra-large pores, named ZEO-1.

Zeolites are crystalline porous materials with important industrial applications, including uses in catalytic processes. The pore apertures limit the access of molecules into and out of the inner confined space of zeolites, where reactions occur.

The research, published in Science, proved that ZEO-1 possesses these “extra-large” pores of around 10 Å (1 angstrom equals one ten billionth of a meter), but also smaller pores of around 7 Å, which is actually the size of traditional “large” pores.

Because of its porosity, strong acidity and high stability, ZEO-1 may find applications as a catalyst in fine chemistry for the production of pharmaceutical intermediates, in controlled substance release, for pollution abatement or as a support for the encapsulation of photo- or electroactive species (they react to light or an electric field).

“The crossings of its cages delimit super boxes, open spaces that can be considered nanoreactors to carry out chemical reactions in their confined space”, explains Miguel A. Camblor, researcher at the Instituto de Ciencia de Materiales de Madrid – CSIC.

To prove that this new zeolite may be useful in applications involving bigger molecules, researchers measured the adsorption to the inner surface of the zeolite of the dye Nile red – a big molecule. Moreover, they tested its performance in fluid catalytic cracking of heavy oil, a process the world still relies on to produce fuels. In both processes, the new zeolite performed better than the conventional large pore zeolite used nowadays.

This research is the result of an international collaboration between eight research centers in China, the USA, Sweden and Spain. The team was led by Fei-Jian Chen (Bengbu Medical College, China), Xiaobo Chen (China University of Petroleum), Jian Li (Stockholm University) and Miguel A. Camblor (Instituto de Ciencia de Materiales de Madrid, CSIC).

Structure determination with synchrotron light

The zeolite was discovered following a high-throughput screening methodology. The structure solution was challenging because the zeolite has a very complex structure, with a small crystal size (<200nm) but an exceedingly large cell volume.

“The combination of electron diffraction data with synchrotron powder X-ray diffraction data collected at the MSPD beamline of the ALBA Synchrotron and the Argonne National Laboratory (USA) made possible the accurate structure determination of ZEO-1″, says Camblor.

Read more on the ALBA website

Image: A perspective view of the extra-large pore of ZEO-1 along (100)

Green hydrogen: Why do certain catalysts improve in operation?

Green hydrogen: Why do certain catalysts improve in operation?

Crystalline cobalt arsenide is a catalyst that generates oxygen during electrolytic water splitting in the production of hydrogen. The material is considered to be a model system for an important group of catalysts whose performance increases under certain conditions in the course of electrolysis. Now a HZB-team headed by Marcel Risch has observed at BESSY II how two simultaneous mechanisms are responsible for this. The catalytic activity of the individual catalysis centres decreases in the course of electrolysis, but at the same time the morphology of the catalyst layer also changes. Under favourable conditions, considerably more catalysis centres come into contact with the electrolyte as a result, so that the overall performance of the catalyst increases.

As a rule, most catalyst materials deteriorate during repeated catalytic cycles – they age. But there are also compounds that increase their performance over the course of catalysis. One example is the mineral erythrite, a mineral compound comprising cobalt and arsenic oxides with a molecular formula of (Co3(AsO4)2∙8H2O). The mineral stands out because of its purple colour. Erythrite lends itself to accelerating oxygen generation at the anode during electrolytic splitting of water into hydrogen and oxygen.

Read more in the HZB website

Image: Schematic of the electrochemical restructuring of erythrite. The fine needle-like structure melts during the conversion from a crystalline material to an amorphous one, which is porous like a Swiss cheese.

Credit: © HZB

In situ spectroscopy as a probe of electrocatalyst performance

In situ spectroscopy as a probe of electrocatalyst performance

Hydrogen fuel cells generally require expensive and scarce platinum catalysts in order to function. Researchers have created highly reactive platinum-nickel nanowires with the potential to reduce the amount of platinum required in fuel cells. Research at PIPOXS examines the atomic-level mechanisms of this catalyst, forming a foundation for the development and commercialization of more efficient fuel cell technology.

What is the new discovery?


The oxygen reduction reaction (ORR) is an important and often limiting component of hydrogen fuel cell operation.  To facilitate this reaction, platinum-based catalysts are often used to increase its rate, though the expense and limited availability of Pt present challenges to its widespread use.  In this work, researchers selectively replaced a portion of the nickel atoms of nickel nanowires with platinum to create platinum-nickel nanowires (PtNi-NWs) as high surface area catalysts that reduced the total amount of platinum required.  These PtNi-NWs were found to be highly active, and so operando x-ray absorption spectroscopy and extended x-ray absorption fine structure (EXAFS) experiments were conducted at the PIPOXS beamline to assess the electronic and geometric changes occurring in these catalysts during their use.   These data enabled the researchers to determine that the Pt formed an alloy with the Ni in the NW and that its interaction with oxygen remained constant regardless of the external potential applied.  

Read more on the CHESS website

Image: Schematic showing the electrochemical cell used for the operando measurements, and how the EXAFS data can be used to deduce the chemistry happening during this reaction.

Helping to neutralise greenhouse gases

Helping to neutralise greenhouse gases

Researchers used the Canadian Light Source (CLS) at the University of Saskatchewan to create an affordable and efficient electrocatalyst that can transform CO2 into valuable chemicals. The result could help businesses as well as the environment.

Electrocatalysts help to collect CO2 pollution and efficiently convert it into more valuable carbon monoxide gas, which is an important product used in industrial applications. Carbon monoxide gas could also help the environment by allowing renewable fuels and chemicals to be manufactured more readily.

The end goal would be to try to neutralize the greenhouse gases that worsen climate change.

Precious metals are often used in electrocatalysts, but a team of scientists from Canada and China set out to find a less expensive alternative that would not compromise performance. In a new paper, the stability and energy efficiency of the team’s novel electrocatalyst offered promising results.

Read more on the Canadian Light Source website

Image : Schematic of an electrochemistry CO2-to-CO reduction reaction.

How a new electrocatalyst enables ultrafast reactions

How a new electrocatalyst enables ultrafast reactions

The work provides rational guidance for the development of better electrocatalysts for applications such as hydrogen-fuel production and long-range batteries for electric vehicles.

The oxygen evolution reaction (OER) is the electrochemical mechanism at the heart of many processes relevant to energy storage and conversion, including the splitting of water to generate hydrogen fuel and the operation of proposed long-range batteries for electric vehicles. Because the OER rate is a limiting factor in such processes, highly active OER electrocatalysts with long-term stability are being sought to increase reaction rates, reduce energy losses, and improve cycling stability. Catalysts incorporating rare and expensive materials such as iridium and ruthenium exhibit good performance, but an easily prepared, efficient, and durable OER catalyst based on earth-abundant elements is still needed for large-scale applications.

Key insight: shorter O-O bonds
In an earlier study, a group led by John Goodenough (2019 Nobel laureate in chemistry) measured the OER activities of two compounds with similar structures: CaCoO3 and SrCoO3. They found that the CaCoO3 exhibited higher OER activity, which they attributed to its shorter oxygen–oxygen (O-O) bonds. Inspired by this, members of the Goodenough group have now analyzed a metallic layered oxide, Na0.67CoO2, which has an even more compact structure than CaCoO3. X-ray diffraction (XRD) experiments performed at the Advanced Photon Source (APS) confirmed that the shortest O-O separation in Na0.67CoO2 is 2.30 Å, compared to 2.64 Å for CaCoO3. The researchers then compared the OER performance of Na0.67CoO2 with IrO2, Co3O4, and Co(OH)2. They found that Na0.67CoO2 exhibited the highest current density, the lowest overpotential (a measure of thermodynamic energy loss), and the most favorable Tafel slope (sensitivity of the electric current to applied potential). The Na0.67CoO2 also showed excellent stability under typical operating conditions.

>Read more on the Advanced Light Source website

Image: (extract, full image here) A new electrocatalyst prepared for this study, Na0.67CoO2, consists of two-dimensional CoO2 layers separated by Na layers (not shown). The Co ions (blue spheres) have four different positions (Co1-Co4), and the distorted Co–O octahedra have varying oxygen–oxygen (O-O) separations (thick red lines connecting red spheres). All of the O-O bonds are shorter than 2.64 Å (the length of the corresponding bonds in a comparable material), and the shortest bonds are less than 2.40 Å. It turns out that O-O separation has a strong effect on the oxygen evolution reaction (OER) in this material.

New catalyst resists destructive carbon buildup in electrodes

New catalyst resists destructive carbon buildup in electrodes

Key challenges in the transition to sustainable energy include the long-duration storage of cheap, renewable electricity and the electrification of the heavy-freight transportation sector. Both challenges can be met using electrochemical cells. Solid oxide electrolysis cells are capable of highly efficient splitting of steam and CO2 to produce a synthetic H2–CO gas mixture (syngas), which can be converted into synthetic hydrocarbon transportation fuels using conventional industrial reactors. However, the efficiency of the process is limited by the risk of destructive carbon deposition inside the cells’ porous solid electrodes. A nickel catalyst is responsible for the carbon growth, but replacing this long-standing conventional catalyst has turned out to be highly challenging.

Now, researchers have used ambient-pressure x-ray photoelectron spectroscopy (APXPS) at ALS Beamlines 9.3.2 and 11.0.2 to probe the mechanisms by which carbon grows on different catalysts during CO2 electrolysis. Gadolinium-doped cerium oxide (GDC) is known to resist carbon growth, and the ambient-pressure experiments probed the degree and mechanism of this carbon resistance. The experimental data, subsequently confirmed by density functional theory calculations, revealed that the carbon atoms are energetically trapped by various oxygen species on the surface of GDC—a capability entirely lacking for nickel.

>Read more on the Advanced Light Source website

Image: Artistic representation of a nickel-based electrode as a broken down fuel pump and of a cerium-based electrode as a new, productive pump. Credit: Cube3D

NSLS-II scientist named DOE Office of Science Distinguished Fellow

NSLS-II scientist named DOE Office of Science Distinguished Fellow

Scientists from the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have garnered two out of five “Distinguished Scientists Fellow” awards announced today by the DOE’s Office of Science.

Theoretical physicist Sally Dawson, a world-leader in calculations aimed at describing the properties of the Higgs boson, and José Rodriguez, a renowned chemist exploring and developing catalysts for energy-related reactions, will each receive $1 million in funding over three years to pursue new research objectives within their respective fields. (…)

José Rodriguez (NSLS-II)

For discoveries of the atomic basis of surface catalysis for the synthesis of sustainable fuels, and for significantly advancing in-situ methods of investigation using synchrotron light sources.”

Rodriguez will devote his funding to the development and construction of new tools for performing extremely rapid, time-resolved measurements to track the reaction mechanisms of catalytic processes as they occur under variable conditions—like those encountered during real-world reactions important to energy applications. These include processes on metal-oxide catalysts frequently used in the production of clean fuels and other “green” chemicals through hydrogenation of carbon monoxide and carbon dioxide, or the conversion of methane to hydrogen.

“At a microscopic level, the structure of a catalyst and the chemical environment around the active sites—where chemical bonds are broken and reformed as reactants transform into new products—change as a function of time, thus determining the reaction mechanism,” said Rodriguez. “We can learn a lot about the nature of the active sites under steady-state conditions, with no variations in temperature, pressure, and reaction rate. But to really understand the details of the reaction mechanism, we need ways to track what happens under transient or variable conditions. This funding will allow us to build new instrumentation that works with existing capabilities so we can study catalysts under variable conditions—and use what we learn to improve their performance.”

>Read more on the NSLS-II website

Synergistic Co−Mn oxide catalyst for oxygen reduction reactions

Synergistic Co−Mn oxide catalyst for oxygen reduction reactions

Researchers employed synchrotron-based X-ray absorption spectroscopy (XAS) at CHESS to investigate the synergistic interaction of bimetallic Co1.5Mn1.5O4/C catalysts… under real-time operando electrochemical conditions.

Identifying the catalytically active site(s) in the oxygen reduction reaction (ORR) is critical to the development of fuel cells and other technologies. Researchers employed synchrotron-based X-ray absorption spectroscopy (XAS) at CHESS to investigate the synergistic interaction of bimetallic Co1.5Mn1.5O4/C catalysts – which exhibit impressive ORR activity in alkaline fuel cells – under real-time operando electrochemical conditions. Under steady state conditions, both Mn and Co valences decreased at lower potentials, indicating the conversion from Mn-(III,IV) and Co(III) to Mn(II,III) and Co(II), respectively. Changes in the Co and Mn valence states are simultaneous and exhibited periodic patterns that tracked the cyclic potential sweeps.

>Read more on the CHESS website

Image: Schematic of the in situ XAS electrochemical cell. Working electrode (WE, catalyst on carbon paper) and counter electrode (CE, carbon rod) were immersed in 1 M KOH solution. The reference electrode was connected to the cell by a salt bridge to minimize IR drops caused by the resistance in the thin electrolyte layer within the X-ray window.