Fuel cell catalysts go sub-nano 

Japanese researchers have created sub-nano scale platinum clusters with high catalytic activity for use in fuel cell applications. The smallest of these particles contains just 12 atoms. 

The team found that as they decreased the size of the clusters, their catalytic activity for the reduction of oxygen increased. At 12 atoms, every atom was exposed at the surface and the catalytic activity was 13 times that of commercial platinum nanoparticles, which contain hundreds or thousands of atoms. 

According to the scientists, platinum nanoparticles of around 3 nanometres are believed to exhibit the best performance, so the fact that their sub-nano clusters work well was not expected. 

The clusters are made by adding platinum(iv) chloride to dendritic phenylazomethine templates - branched molecules that function as rigid, cage-like structures in which the metal atoms become trapped. The number of metal coordination sites, and therefore platinum atoms, in each cage can be tightly controlled. And the platinum clusters can be released using a reducing agent. 

Publishing in Nature Chemistry  (DOI: 10.1038/nchem.288), the researchers say that the improved performance is probably not due to an increase in surface area but to quantum size effects that are not yet fully understood. 

Nobel laureates call for energy funding

34 Nobel prize winners, including six researchers who won the award for chemistry, are urging US President Obama to make good on his pledge to provide increased, stable funding for energy research and development.  

The scientists are concerned that the climate change and energy legislation that is currently going through Congress would provide only a fraction of the $150 billion (£91 billion) that Obama proposed to go to a so-called clean energy technology fund over ten years.   

Read more on laureates' views on energy and climate change in this month's feature article, Living the Nobel life. 

Sunlight splitting catalys t 

Chinese scientists have boosted the efficiency of light-driven water splitting and made a catalyst that produces hydrogen from water and sunlight. Oxygen from the water splitting reaction is mopped up by sacrificial sodium sulfide and sulfate. 

By adding small amounts of platinum metal and palladium sulfide to a cadmium sulfide catalyst, the team managed to extend the range of wavelengths over which the catalyst was active from ultraviolet into the visible spectrum while maintaining exceptionally high quantum efficiency. Over 90 per cent of the photons absorbed led to the formation of molecular hydrogen, compared to about 60 per cent for CdS catalysts doped with platinum alone. The work is reported in the Journal of Catalysis (DOI: 10.1016/j.jcat.2009.06.024). 

Cefic banned from lobbying

The European chemical industry council (Cefic) has been suspended from lobbying the European Commission for eight weeks, following an allegation that they had under-reported their lobbying costs for 2007.  

Cefic is a trade organisation representing 29,000 European chemical companies, and one of its roles is to lobby the EU regulators on the industry's behalf. The complaint came from Friends of the Earth Europe, who alleged that Cefic had declared spending an unrealistically low proportion of their budget on lobbying. Cefic claimed to have spent just 0.1 per cent of its 2007 budget, equating to less than 50 000 (£43,000). The EC agreed that the figure was an underestimate, and therefore a temporary ban was put in place.  

Shedding light on Neanderthals

A new technique has been used to analyse the mitochondrial DNA of five Neanderthals. 

Last year, a German team produced the first complete Neanderthal mitochondrial DNA genome. However, the technique sequences everything in a sample, when only about 1 per cent of it belongs to the Neanderthal's mitochondria. Now, they have developed a less wasteful method that replicates all the DNA in a sample, and then uses tags to retrieve the required DNA before analysis. 

By comparing the DNA sequences to each other and to modern man, the team calculated that Neanderthals have one third of the genetic diversity of man today. This research is reported in Science (DOI: 10.1126/science.1174462).

Sticky nanotubes detect bacteria

Sticky nanotubes, that trap microbes like flypaper, could be used to rapidly identify bacteria in food and medical samples, according to Spanish chemists. 

Their technique uses carbon nanotubes coated with aptamers - short strands of genetic material that bind tightly to specific bacteria. Electrodes coated with these sticky nanotubes are then dipped into a test liquid. The bacteria stick to the aptamers, which partially peel away from the nanotubes, changing their electrical conductivity. By measuring this change, the number of bacteria in the solution can be calculated. The work is published in Angewandte Chemie International Edition (DOI: 10.1002/anie.200902090). 

Illuminating the black art of crystallisation

UK chemists have harnessed the power of lasers to trigger controlled crystallisation. By pulsing near-infrared laser light at agarose gels saturated with either potassium iodide (KI) or lysozyme from egg white, the team from the University of Edinburgh could induce formation of tiny single crystals with pinpoint accuracy.

Publishing in the Journal of the American Chemical Society  (DOI: 10.1021/ja905232m), the team demonstrated the technique by firing the laser through a template to write the word 'laser' by forming KI crystals in agarose gel. The method can be modified to give three dimensional resolution by using two crossed lasers - crystals are only nucleated at the intersection of the beams. 

The low power of the laser means it won't affect the chemistry of the sample, so the team are hopeful that it will help produce crystals of proteins and other molecules that are otherwise tricky to crystallise for structural characterisation. However, they must first determine how general the technique is, since they have currently only tried it on materials that readily crystallise. 

US chemical law controversy   

The US chemical industry is becoming divided over plans to update the law governing the regulation of chemicals in the country. In July, the US Environmental Protection Agency (EPA) announced that it was re-evaluating its chemical management system (see Chemistry World, August 2009, p14), and now two large US-based trade associations have sent conflicting messages to Washington concerning how best to do this.  

The American Chemical Council (ACC) has requested that the 30 year old Toxic Substances Act, of which chemical management is included, is overhauled and 'updated to keep pace with science'. Whereas the Society of Chemical Manufacturers and Affiliates (Socma) has warned that a regulatory overhaul in the current economic climate could have disastrous consequences. 

Healing nanosheet 

Biodegradable nanomaterials could prevent scarring after surgery according to Japanese researchers. They claim their polyester-based nanosheets may make having stitches a thing of the past.  

The nanosheets are made from poly(L-lactic acid) (PLLA), which has been used before as degradable stitches. The sheets are formed by spin-coating PLLA on a silicon dioxide substrate, and then transferring them to a supporting poly(vinyl alcohol) film. After taping these sheets across incision sites, the supporting films are dissolved using a saline solution. This research is reported in Advanced Materials (DOI: 10.1002/adma.200901035).