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The properties of the catalyst based on structurally disordered Pd−P nanoparticles supported on a carbon support (Pd−P/C) in the preparation of hydrogen peroxide by the anthraquinone method have been studied. It is shown that a high yield of H2O2 is observed upon sequential hydrogenation of 2000 mol of eAQ (mol Pd)−1. The H2O2 yield reaches 96 %–97 %. Pd−P nanoparticles are more active in the hydrogenation of 2‐ethyl‐9,10‐anthraquinone than Pd6P crystalline phosphide. In terms of H2O2 yield, Pd−P/C catalysts are superior to known catalysts: Pd/C, Pd/Al2O3. Based on the data of X‐ray powder diffraction, X‐ray photoelectron spectroscopy, Inductively Coupled Plasma and thermogravimetry, the main reasons for the deactivation of Pd−P/C catalysts have been established. Crystallization of the structurally disordered Pd−P nanoparticles, poisoning by eAQ conversion products and leaching of the active component are considered to be possible reasons of the Pd−P/C catalyst deactivation. [ABSTRACT FROM AUTHOR]

Background: In crustaceans, several mechanisms provide for the mechanical strength of the cuticular "tools" (dactyli, claws, jaws), which serve to catch and crush food objects. Studies on the mandibles of the endemic Baikal amphipod Acanthogammarus grewingkii by means of electron microscopy and elemental analysis have revealed specific structural features of these mouthparts. Methodology: The fine structure of the mandible has been studied by means of SEM, TEM, and AFM; methods used to analyze its elemental and phase composition include XEPMA, XPS, SEM-EDS analysis, and XRD. Conclusion: Functional adaptations of the mandible in A. grewingkii provide for the optimum combination of mechanical hardness and fracture resistance, which is achieved due to a complex structure and composition of its cutting parts. Teeth of the mandible are covered by a thin layer of silica (10-20 mm). Their epicuticle is characterized by a high density, consists of three layers, and increases in thickness toward the tooth apex. The epicuticle is enriched with Br, while the concentrations of Ca and P reach the peak values in the softer internal tissues of the teeth. These data broaden the view of the diversity of adaptation mechanisms providing for the strengthening of cuticular "tools" in crustaceans [ABSTRACT FROM AUTHOR]

Background: In crustaceans, several mechanisms provide for the mechanical strength of the cuticular "tools" (dactyli, claws, jaws), which serve to catch and crush food objects. Studies on the mandibles of the endemic Baikal amphipod Acanthogammarus grewingkii by means of electron microscopy and elemental analysis have revealed specific structural features of these mouthparts., Methodology: The fine structure of the mandible has been studied by means of SEM, TEM, and AFM; methods used to analyze its elemental and phase composition include XEPMA, XPS, SEM-EDS analysis, and XRD., Conclusion: Functional adaptations of the mandible in A. grewingkii provide for the optimum combination of mechanical hardness and fracture resistance, which is achieved due to a complex structure and composition of its cutting parts. Teeth of the mandible are covered by a thin layer of silica (10-20 µm). Their epicuticle is characterized by a high density, consists of three layers, and increases in thickness toward the tooth apex. The epicuticle is enriched with Br, while the concentrations of Ca and P reach the peak values in the softer internal tissues of the teeth. These data broaden the view of the diversity of adaptation mechanisms providing for the strengthening of cuticular "tools" in crustaceans.