In a case of the Goldilocks story retold at the molecular level, scientists at Argonne National Laboratory and Northwestern University have discovered a new path to the development of more stable and efficient catalysts. The research team sought to create "nanobowls"—nanosized bowl shapes that allow inorganic catalysts to operate selectively on particular molecules.
Modern advances in well controlled fabrication of metal nanoparticles and their composites have assisted material scientists in the design and efficient utilization of desired catalysts, as is evidenced by explosive growth in the nanocatalysis field. A new review published in Advanced Energy Materials highlights the progress of nanocatalysis through rational design.
Sulfur compounds in petroleum fuels have met their nanostructured match. University of Illinois researchers developed mats of metal oxide nanofibers that scrub sulfur from petroleum-based fuels much more effectively than traditional materials.
A research group at NIST has developed a relatively simple, fast, and effective method of depositing uniform, ultrathin layers of platinum atoms on a surface. The new process exploits an unexpected feature of electrodeposition of platinum—if you drive the reaction much more strongly than usual, a new reaction steps in to shuts down the metal deposition process, allowing an unprecedented level of control of the film thickness.
A chemical nanostructure developed by Boston College researchers behaves much like the pores of the skin, serving as a precise control for a typically stubborn method of catalysis that is the workhorse of industrial chemistry.
Colloidal suspensions of metal nanoparticles in water passes too easily through commonly used macroporous polymeric membranes. To handle these nanofluids, researchers have built a membrane equipped functionalized proteins that can act as filters for nanoscaled particles in aqueous solutions. Such a nano-sieve could act as a catalyzer or could capture solar energy.
Scientists in Japan have developed a high activity gold nanoparticle catalyst that simplifies the function of enzymes in capturing substances. This new type of catalyst mimics enzyme function on the surface of cell membranes, which capture molecules of designated lengths and shapes. The findings indicate that gold nanoparticles thus equipped could support biological activities as a catalyst in the reactions of the living body.
Photoelectrochemical (PEC) tandem solar cells offer a way to produce hydrogen directly from water. But efforts to produce an efficient cell have only resulted in extremely expensive prototypes. Researchers in Switzerland have recently developed a PEC, however, that is made from inexpensive materials and achieves up to 16% efficiency.
Catalysis is an incredibly valuable tool in the field of chemistry, but it typically requires precious metals that are both expensive and potentially harmful to the environment. Researchers in Sweden say they have discovered that copper, which is not typically known for its catalytic properties, had unexpectedly been responsible for catalytic activity as part of research into iron catalysts.
Oxide catalysts play an integral role in many chemical transformations. Greener, more efficient chemical processes would benefit greatly from solid oxide catalysts that are choosier about their reactants, but achieving this has prove a challenge. Now, a team of researchers have developed a straightforward and generalizable process for making reactant-selective oxide catalysts by encapsulating the particles in a sieve-like film that blocks unwanted reactants.
Through spectroscopic investigations on a hydrogen-producing enzyme, researchers in Germany have found that environment of the catalytic site acts as an electron reservoir in the enzyme. This finding means that the enzyme can produce hydrogen at a highly efficient rate and could be useful as a renewable energy source.
Hydrogen production by solar water splitting in photoelectrochemical cells (PEC) has long been considered the holy grail of sustainable energy research. Iron oxide is a promising electrode material, and now an international team of researchers gained in-depth insights into the electronic structure of an iron oxide electrode, while it was in operation. This opens up new possibilities for an affordable hydrogen production from solar energy.
Solar, wind and other renewable energy sources reduce consumption of fossil fuels but also pose challenges to the electrical grid because their power generation fluctuates. A team of researchers at Stanford and SLAC National Accelerator Laboratory has developed a mix of materials that shows promise as a cost-effective alternative to standard batteries—able to quickly and efficiently charge and discharge their energy over thousands of charges, with no energy loss after 1,000 charges.
Platinum works well as a catalyst in hydrogen fuel cells, but it has at least two drawbacks: It is expensive, and it degrades over time. Brown University chemists have engineered a cheaper and more durable catalyst using graphene, cobalt, and cobalt-oxide—the best nonplatinum catalyst yet.
Lawrence Berkeley National Laboratory researchers have combined the best properties of heterogeneous and homogeneous catalysts by encapsulating metallic nanoclusters within the branched molecular arms of dendrimers. The results are heterogenized homogeneous nanocatalysts that are sustainable and feature high reactivity and selectivity.
The tiny metal particles in catalytic converters that work to clean up vehicle emissions require a minimum temperature to function efficiently, and work poorly when cold. A new measuring method using photoemission electron microscopy has made it possible to examine many different types of these particles at the same time, shedding light on what exactly affects converter efficiency.
Hydrogen gas that is created using solar energy to split water into hydrogen and oxygen has the potential to be a cost-effective fuel source if the efficiency of the catalysts used in the water-splitting process can be improved. By controlling the placement of key additives in an iron oxide catalyst, researchers from NIST have found that the final location of the dopants and the temperature at which they are incorporated into the catalyst crystal lattice determine overall catalytic performance in splitting water.
By modeling a cadmium sulfide–zinc sulfide alloy with special computational techniques, a Singapore-based research team has identified the key photocatalytic properties that enable this chemical duo to 'split' water molecules into a fuel, hydrogen gas. The breakthrough is significant because each of these semiconductors had previously been limited by their bandgap potential.
Zeolites, porous materials used in commercial products such as cat litter and washing detergents, are attracting the attention of researchers hoping to design better catalysts. Chemical engineers in Switzerland recently brought to bear the latest imaging technologies to examine a newly developed zeolite catalyst applied in the chemical conversion of xylene. It represents one of the most complex organized porous materials known.
Though costly to produce, hydrogen is crucial for the oil-refining industry and the production of essential chemicals such as the ammonia used in fertilizers. The recent invention of a new photocatalyst may help the efficiency of this process. Nanometer-scale “Janus” structures consisting of cheap metal and oxide spheres were recently demonstrated as an excellent catalyst for a hydrogen-production reaction powered only by sunlight.
Northwestern University researchers have broken a world record by creating two new synthetic materials with the greatest amount of surface areas reported to date. Named NU-109 and NU-110, the materials belong to a class of crystalline nanostructure known as metal-organic frameworks (MOFs) that are promising vessels for natural gas storage for vehicles, catalysts, and other sustainable materials chemistry.
A team of researchers has recently been successful in synthesizing and characterizing monodisperse gold-core silver-shell nanoparticles utilizing a bio-template that has potential as a water soluble catalyst for converting biomass such as dead trees, branches and tree stumps, yard clippings, wood chips, and even municipal solid waste into fuels.
Scientists and engineers are working to find a way to power the planet using solar-powered fuel cells. Such green systems would split water during daylight hours, generating hydrogen that could then be stored and used later to produce water and electricity. But robust catalysts are needed to drive the water-splitting reaction. Chemists at Caltech have determined the dominant mechanism for cobalt catalysts, a cheaper alternative to platinum catalysts.
By modifying the rate at which chemical reactions take place, nanoparticle catalysts fulfill myriad roles in industry, the biomedical arena, and everyday life. Finding new and more effective nanoparticle catalysts to perform applications in these areas has become vital. Now, a researcher at Arizona State University has found a clever way to measure catalytical reactions of single nanoparticles and multiple particles printed in arrays, which will help to characterize and improve existing nanoparticle catalysts.
Scientists at the University of Cambridge have produced hydrogen, a renewable energy source, from water using an inexpensive catalyst under industrially relevant conditions—using pH neutral water, surrounded by atmospheric oxygen, and at room temperature.