New Fuel Cells and Catalytic Materials
Russian researchers have achieved controlled production of nanoscale complex oxides in combustion reactions
Obtaining nanoscale complex oxides in combustion reactions (an equivalent of self-propagating high-temperature synthesis) is one of the convenient, universal and widely used methods. That being said, the already existing effect of thermochemical generation of charges in precursors hasn't been previously known to scientists. According to the project manager, a seemingly not very successful experiment with a polymer-containing composition in the Paul Scherrer Institute in Switzerland, when a cloud of synthesis products literally soared above the reaction vessel, made it possible to assume the existence of such effect.
'It was possible, of course, not to pay attention to the 'embarrassing' incident, but the inquisitive mind and scientific curiosity instilled in us by our teachers did not allow this to happen,' Ostroushko says. 'As a result of new elaborate experiments, the reason for the effect obtained became clear: the particles bounce off of each other under the influence of powerful similar charges. In all fairness, it should be noted that the presence of charged particles per se in a flame at high temperature has been known for a long time.'
Electron microscopy made it possible for scientists to understand that in systems where high-density charges arise, nanoparticles turn out to be connected to each other rather loosely. In functional ceramics or coatings manufacturing, such a complex oxide is intensively agglomerated at a significantly lower temperature than the composite oxide after synthesis with relatively low charges.
'All of the above allows us to control the processes of ceramics formation, to produce compositions with layers of different composition (for example, electrode and oxygen-conducting membrane of the fuel cell) in one cycle, adjusting the agglomeration temperature of the components to each other easily and neatly,' the scientist notes. 'According to preliminary estimates, the improvement and simplification of the technology allows to reduce the cost of production by at least 30-40%, to increase the yield of qualified products, preventing the cracking of layers of planar or axial complex oxide compositions. Using the new method of purposeful regulation of the properties of complex oxides, it is possible to obtain catalytic coatings that are resistant to high temperatures as well as many other useful substances.'
In addition to creating new current sources, fuel cells, the results of such work can be used to create catalytic, magnetic, superconducting and sensory materials in the future. According to experts, the UrFU scientists are in many ways pioneers in conducting scientific research in this area. The work of the team is aimed at an in-depth, fundamental study of the phenomenon of charge generation, the search for new patterns and the possibilities of its practical application.
Influence of synthesis conditions on phase formation and functional properties of prospective anode material Sr2Ni0.75Mg0.25MoO6-δ:
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