Synthesis of oxides and determination of uranium concentration in uranyl nitrate compounds using irradiation by double laser pulses

Abstract

Spectroscopic studies of the surface of a porous solid containing micro amounts of uranyl nitrate hexahydrate using irradiation by two sequential pulses with pulse-to-pulse intervals in the range 4-12 μs have shown that laser chemical synthesis of uranium and uranium oxide nanoclusters within the interior of a porous solid is a promising technique, with the possibility at the same time of determining the uranium content with good sensitivity (~10 -10 g). Introduction. Research in the field of nanoclusters and nanosystems provides a basis for designing new 21stCentury technology: nanotechnology. Thus, for example, cluster catalysts make it possible to develop new directions in control of conversions and selectivity of catalytic reactions as a result of the cluster size and its interaction with the matrix [1]. Uranium oxides are quite attractive for catalysis due to the possibility of varying their stoichiometry over a broad range and varying the valence state of uranium depending on external conditions (temperature, amount of oxygen). In [2,3], it is shown that catalysts based on uranium oxides are active in reactions of exhaustive oxidation of hydrocarbons at low temperatures, and are resistant to the action of such catalytic poisons as sulfur, water, and halogens. We know that uranium oxide catalysts can also be used in partial oxidation processes [4,5]. Mixed Ni-U oxide systems are efficient in processes of conversion of methane to synthesis gas [1,6]. Uranium catalysts in the original state can contain compounds of the 3-, 4-, 5-, or 6-valent metal. This provides more diversity in the composition of active sites than when using derivatives of lanthanides, which generally have a trivalent state [7].