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Electron highway for hydrogen and carbon dioxide storage discovered

FRANKFURT/MARBURG/BASEL. In 2013, a team of microbiologists led by Professor Volker Müller of Goethe University Frankfurt discovered an unusual enzyme in heat-loving (thermophilic) bacteria: hydrogen-dependent CO. 2 HDCR reductase. It produces formic acid (formic) from hydrogen gas (H 2 ) and carbon dioxide (CO 2 ), and in the process, hydrogen transfers electrons to carbon dioxide. This makes HDCR the first known enzyme to directly utilize hydrogen. On the other hand, all the enzymes known to date that produce formic acid took a detour: they obtained electrons from soluble cellular electron transfer agents, which for their part accepted electrons from hydrogen with the help of other enzymes. The bacterium Thermoanaerobacter kivui thrives away from oxygen, for example in the deep ocean, and uses CO 2 and hydrogen to produce cellular energy. HDCR from Thermoanaerobacter kivui consists of four protein modules: one that cleaves hydrogen, one that produces formic acid and two small

Solar-powered chemistry uses carbon dioxide and water to make raw materials for fuels, chemicals

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Diagram of a semiconductor nanowire made of indium, gallium, and nitrogen—decorated with gold and chromium oxide nanoparticles. When light hits the nanowire, it liberates electrons and positively charged “holes” that the electrons leave behind. In the nanowires themselves, the holes oxidize water to protons (hydrogen) and oxygen. Meanwhile, some of the electrons are drawn into the metal nanoparticles, where they break down the carbon dioxide. The molecules recombine into carbon monoxide, hydrogen and methane molecules to form syngas. Credit: Roksana Rashid, McGill University. Solar-powered synthesis gas can recycle carbon dioxide into useful fuels and chemicals, an international research team has shown. “If we can produce syngas from carbon dioxide using only solar energy, we can use this as a precursor for methanol and other chemicals and fuels. This will significantly reduce the overall CO. 2 emissions,” said Zetian Mi, professo