Platinum nanoparticles may radically improve fuel cells

This nanotech-based catalyst would put electric cars — among other ideas and products — on a much faster track.

From the link:

In the quest for efficient, cost-effective and commercially viable fuel cells, scientists at Cornell University’s Energy Materials Center have discovered a catalyst and catalyst-support combination that could make fuel cells more stable, conk-out free, inexpensive and more resistant to carbon monoxide poisoning.

The research, “Highly Stable and CO-Tolerant Pt/Ti_0.7W_0.3O₂ Electrocatalyst for Proton-Exchange Membrane Fuel Cells,” (Journal of the American Chemical Society, July 12, 2010) led by Hector D. Abruna, Cornell professor of Chemistry and Chemical Biology and director of the Energy Materials Center at Cornell (emc2); Francis J. DiSalvo, Cornell professor Chemistry and Chemical Biology; Deli Wang, post doctoral researcher; Chinmayee V. Subban, graduate student; Hongsen Wang, research associate; and Eric Rus, graduate student.

Hydrogen fuel cells offer an appealing alternative to gasoline-burning cars: They have the potential to power vehicles for long distances using hydrogen as fuel, mitigate carbon dioxide production and emit only water vapor.

However, fuel cells generally require very pure hydrogen to work. That means that conventional fuels must be stripped of carbon monoxide – a process that is too expensive to make fuel cells commercially viable.

Fuel cells work by electrochemically decomposing fuel instead of burning it, converting energy directly into electricity

Solar may be ready to pop …

… if this tech holds the promise that looks, well, promising.

From the link:

Sun + Water = Fuel

With catalysts created by an MIT chemist, sunlight can turn water into hydrogen. If the process can scale up, it could make solar power a dominant source of energy.

“I’m going to show you something I haven’t showed anybody yet,” said Daniel Nocera, a professor of chemistry at MIT, speaking this May to an auditorium filled with scientists and U.S. government energy officials. He asked the house manager to lower the lights. Then he started a video. “Can you see that?” he asked excitedly, pointing to the bubbles rising from a strip of material immersed in water. “Oxygen is pouring off of this electrode.” Then he added, somewhat cryptically, “This is the future. We’ve got the leaf.”

What Nocera was demonstrating was a reaction that generates oxygen from water much as green plants do during photosynthesis–an achievement that could have profound implications for the energy debate. Carried out with the help of a catalyst he developed, the reaction is the first and most difficult step in splitting water to make hydrogen gas. And efficiently generating hydrogen from water, Nocera believes, will help surmount one of the main obstacles preventing solar power from becoming a dominant source of electricity: there’s no cost-effective way to store the energy collected by solar panels so that it can be used at night or during cloudy days.

Nanoscale chemical reactors

From the release:

19 September 2008

Introducing the next generation of chemical reactors

Unique nanostructures which respond to stimuli, such as pH, heat and light will pave the way for safer, greener and more efficient chemical reactors.

Being developed by a consortium of UK universities, the nanostructures can regulate reactions, momentum, and heat and mass transfer inside chemical reactors. This technology will provide a step change in reactor technology for the chemical, pharmaceutical and agrochemical industries.

Professor Yulong Ding of the Institute of Particle Science and Engineering at the University of Leeds explains: “This research programme is an important step towards producing the next generation of smart “small footprint”, greener reactors. The responsive reaction systems we are investigating could make the measurement systems currently used in reactors redundant.”

The technique is being developed through a collaborative research programme initiated by Professor Ding together with Dr Alexei Lapkin at the University of Bath, and Professor Lee Cronin at the University of Glasgow.

The programme involves designing and producing molecular metal oxides and polymers as building blocks, and engineering those blocks to form nanoscale structures, which are responsive to internal and / or external stimuli such as pH, heat or light. The structures can be dispersed in fluid, or coated on the reactor walls.

As conditions inside the reactor change, the nanostructured particles will respond by changing their size, shape, or structure. These changes could in turn alter transport properties such as thermal conductivity and viscosity, and catalyst activity – and hence regulate the reactions.

Professor Ding also believes that these systems also have the potential to eliminate the risk of ‘runaway’, where a chemical reaction goes out of control.

The three-year programme, funded by the Engineering and Physical Sciences Research Council (EPSRC), brings together leading experts in the fields of Chemistry, Chemical Engineering and Particle Science & Engineering.

Notes for editors:

1. The Faculty of Engineering at the University of Leeds comprises five Schools:

Civil Engineering; Computing; Electronic and Electrical Engineering; Mechanical Engineering and Process, Materials and Environmental Engineering. All schools in the Faculty have the highest 5 or 5* Research Assessment Exercise ratings, top teaching assessments and strong industrial connections. There are approximately 3,000 students in the Faculty, 80% undergraduates and 20% postgraduates. Two-thirds of our students are from the UK with the remainder representing over 90 different nationalities.

2. The University of Leeds is one of the largest higher education institutions in the UK with more than 30,000 students from 130 countries. With a total annual income of £422m, Leeds is one of the top ten research universities in the UK, and a member of the Russell Group of research-intensive universities. It was recently placed 80th in the Times Higher Educational Supplement’s world universities league table and the University’s vision is to secure a place among the world’s top 50 by 2015.

3. Founded in 1451, the University of Glasgow is one of the top 100 universities in the world with an international reputation for its research and teaching and an important role in the cultural and commercial life of the country. The University is a major research powerhouse, with annual research contract income in the top ten of UK universities. An exceptional 96 per cent of its research-active staff are in areas which have been independently assessed as producing research of international importance.

4. The University of Bath is one of the UK’s leading universities, with an international reputation for quality research and teaching.

View a full list of the University’s press releases: http://www.bath.ac.uk/pr/releases

5. The Engineering and Physical Sciences Research Council (EPSRC) is the UK’s main agency for funding research in engineering and the physical sciences. The EPSRC invests around £800 million a year in research and postgraduate training, to help the nation handle the next generation of technological change. The areas covered range from information technology to structural engineering, and mathematics to materials science. This research forms the basis for future economic development in the UK and improvements for everyone’s health, lifestyle and culture. EPSRC also actively promotes public awareness of science and engineering. EPSRC works alongside other Research Councils with responsibility for other areas of research. The Research Councils work collectively on issues of common concern via Research Councils UK. www.epsrc.ac.uk/

Nanoclusters of gold are valued catalysts

From the press release:

Electron micrographs showing inactive (left) and active (right) catalysts consisting of gold particles absorbed on iron oxide. The red circles indicate the presence of individual gold atoms. The yellow circles show the location of subnanometer gold clusters that can effectively catalyze the conversion of carbon monoxide to carbon dioxide. One nanometer is about half the size of a DNA molecule. (Color added for clarity)Credit: Lehigh University Center for Advanced Materials and Nanotechnology

NIST and partners identify tiny gold clusters as top-notch catalysts

For most of us, gold is only valuable if we possess it in large-sized pieces. However, the “bigger is better” rule isn’t the case for those interested in exploiting gold’s exceptional ability to catalyze a wide variety of chemical reactions, including the oxidation of poisonous carbon monoxide (CO) into harmless carbon dioxide at room temperatures. That process, if industrialized, could potentially improve the effectiveness of catalytic converters that clean automobile exhaust and breathing devices that protect miners and firefighters. For this purpose, nanoclusters—gold atoms bound together in crystals smaller than a strand of DNA—are the size most treasured.

Using a pair of scanning transmission electron microscopy (STEM) instruments for which spherical aberration (a system fault yielding blurry images) is corrected, researchers at the National Institute of Standards and Technology (NIST), Lehigh University (Bethlehem, Pa.) and Cardiff University (Cardiff, Wales, United Kingdom) for the first time achieved state-of-the-art resolution of the active gold nanocrystals absorbed onto iron oxide surfaces. In fact, the resolution was sensitive enough to even visualize individual gold atoms.

The work is reported in the Sept. 5, 2008, issue of Science.

Surface science studies have suggested that there is a critical size range at which gold nanocrystals supported by iron oxide become highly active as catalysts for CO oxidation. However, the theory is based on research using idealized catalyst models made of gold absorbed on titanium oxide. The NIST/Lehigh/Cardiff aberration-corrected STEM imaging technique allows the researchers to study the real iron oxide catalyst systems as synthesized, identify all of the gold structures present in each sample, and then characterize which cluster sizes are most active in CO conversion.

The research team discovered that size matters a lot—samples ranged from those with little or no catalytic activity (less than 1 percent CO conversion) to others with nearly 100 percent efficiency. Their results revealed that the most active gold nanoclusters for CO conversion are bilayers approximately 0.5-0.8 nanometer in diameter (40 times smaller than the common cold virus) and containing about 10 gold atoms. This finding is consistent with the previous surface science studies done on the gold-titanium oxide models.

 

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A.A. Herzing, C.J. Kiely, A.F. Carley, P. Landon and G.J. Hutchings. Identification of active gold nanoclusters on iron oxide supports for CO oxidation. Science, Vol. 321, Issue 5894, Sept. 5, 2008.