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N°29 I quarterly I Ap ril 2013 Live from the Labs | 13 w Chemistry Researchers have developed two cobalt-based materials to replace platinum in hydrogen production, rendering the process a thousand times cheaper. Greener Hydrogen Production And more news... Greenland Paleoclimate Lupus Treatment w During the last interglacial was probably caused by Antarctic period—between 130,000 and ice melt. These results were 125,000 years ago—the climate of obtained through the drilling and northern Greenland was 4 to 8°C analysis of a 2450 meter-long ice warmer than today, but the ice core by an international team sheet melt accounted for only 2 of involved in the NEEM2 project. the 4-6 meter rise in sea levels 01. D. Dahl-Jensen et al. Nature, 2013. 493: 489-94. during that period.1 The remainder 02. North Greenland Eemian Ice Drilling. w LupuzorTM, a synthetic peptide developed in collaboration with Immupharma, caused regression of the autoimmune disease systemic lupus erythematosus in 62% of patients treated in a clinical trial involving 149 sufferers.1 Should these effects be confirmed in a phase-III trial, LupuzorTM could soon be marketed as a new treatment against this very disabling disease. 01. Zimmer R. et al., Ann Rheum Dis., 2012. doi: 10.1136/annrheumdis-2012-202460. BY Ed y Delcher Used to break down crude oil into gasoline or produce ammonia for fertilizers, hydrogen plays an important role in a number of industries. Because it can be stored, it is also regarded as a viable vector for other sources of renewable energies, like solar and wind power, which still lack the stability required to be fully reliable. Because hydrogen is rarely found in its molecular form, it is generally created using a nonrenewable source: natural gas. Yet there is another well-known and far greener method of producing hydrogen: electrolysis. Put simply, when an electric current passes through water (H2O), the voltage difference between the two electrodes splits the water molecules. Through electron transfer between water and the electrodes, hydrogen (H2) and oxygen (O2) molecules are formed. The problem with electrolysis is that catalysts, made of rare metals such as platinum, must be deposited onto the electrodes to accelerate the reactions and improve the efficiency of the process. The cost of such metals is prohibitive, thus hampering any long-term development. However, research teams from CNRS, CEA, and Joseph Fourier University1 have devised two novel approaches to replace these rare metals with widely available cobalt-based materials. The first one, inspired by biochemical processes through which certain organisms use commonplace metals to create hydrogen, relies on cobalt molecules immobilized on carbon nanotubes to catalyze the reaction.2 “These molecules react with the water’s protons to form a cobalt-hydride compound which mimics platinum’s catalytic properties, while being a thousand times cheaper,” explains Vincent Artero, who has been heading the project since 2002. The second approach3 revolves around a bi-functional cobalt-based material named “Janus,” after the twoheaded Roman god. This compound acts as a switchable catalyst, meaning it can favor either oxygen or hydrogen production depending on the electrode’s potential by altering its composition during the reaction. “We do not yet fully understand the process, but its advantages are clear: the catalyst is simple to prepare and highly stable,” says Artero. These new materials could be incorporated into artificial photosynthesis systems to produce “clean” hydrogen from water and solar energy. “Using natural gas is still cheaper though, so industrial electrolysis to produce hydrogen for fuelling purposes should not see the light of day until 2050,” concludes Artero. 01. Laboratoire de chimie et de biologie des métaux (CEA / CNRS / Université Joseph Fourier) ; Institut de recherches en technologie et sciences pour le vivant ; Institut rayonnement et matière à Saclay ; CEA-Liten ; and CEA-Leti (département des micro-technologies pour la biologie et la santé). 02. V. A rtero et al., “Molecular Engineering of a Cobalt-based Electrocatalytic Nano-Material for H2 Evolution under Fully A queous Conditions,” Nature Chemistry, 2013. 5:48-53. 03. V. A rtero et al., “A Janus cobalt-based catalytic material for electro-splitting of water,” Nature Materials, 2012. 11: 802-7. Contact information: LC BM, Grenoble. Vincent Artero > vincent.artero@cea.fr Grenoble © V Artero /CEA q S canning electrochemical micrograph of the cobalt-based “Janus” material showing its oxidative and reductive sides.


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