Facile wet-chemical synthesis of differently shaped cuprous oxide particles and a thin film: Effect of catalyst morphology on the glucose sensing performance

Abstract In this work, different facile synthesis routes were developed to create cuprite-based catalyst systems for the amperometric detection of glucose, allowing us to evaluate the impact of important electrode fabrication parameters on the glucose sensing performance. Using homogenous precipitation routes based on a redox system, two differently shaped cuprite particles - skeletons and polyhedrons - could be obtained. Furthermore, a novel electroless deposition technique was introduced that does not require sensitization and activation pretreatments, allowing for the direct modification of the glassy carbon. This technique produced electrodes with dense thin film consisting of merged, octahedral cuprite crystals. Afterward, these materials were tested as potential catalysts for the electrochemical detection of glucose. While the catalyst powders obtained by precipitation required NafionR to be attached to the electrode, the thin film synthesized using electroless plating could be realized with and without additive. Summarizing the results, it was found that NafionR was not required to achieve glucose selectivities typically observed for cuprite catalysts. Also, the type of catalyst application (direct plating vs. ink drop coating) and the particle shape had a pronounced effect on the sensing performance. Compared to the thin film, the powder-type materials showed significantly increased electrochemical responses. The best overall performance was achieved with the polyhedral cuprite particles, resulting in a high sensitivity of 301 μA mmol-1 cm-2, a linear range up to 298 μmol L-1 and a limit of detection of 0.144 μmol L-1

Similarities and Differences in Explosion Hazards of Organic Peroxides and High Explosives: an Experimental Study

Properties that cause explosion hazard of organic peroxides, hydroperoxides and nitrocompounds are examined in the article. Ability to thermal explosion initiation of benzoyl peroxide and of nitrocompounds is compared. Explosion properties of peroxides are analyzed. Measurements of burning temperature by means of micro thermocouples and the comparison of their values with the calculated ones of benzoyl peroxide and hydroperoxide of isopropyl benzene lead to the conclusion that burning of them propagates in condensed phase. It is noted that heat instability of benzoyl peroxide burning, contrary to many nitrocompounds, is absent. Burning of benzoyl peroxide is stable even in vacuum. It is noted that, although benzoyl peroxide is not applied as explosive, in some cases the explosion hazard of benzoyl peroxide heating can be bigger than that of PETN. This conclusion was made on the basis of an investigation carried out by means of DSC method. The explosion process of benzoyl peroxide and hydroperoxide of isopropyl benzene propagates in a regime reminiscent of a low velocity detonation and the explosive effects are suffcient for severe destructions during accidents. This conclusion unfortunately is confrmed by bitter experience in practice. The results of the investigation of condensed products of explosion at impact of mixtures aluminum with peroxides and with nitrocompounds by means of impact-testing machine that were carried out in this work by X-ray diffraction analysis are discussed. It was shown that if the temperature of explosion of a mixture is Tp ≥ 2200-2300 K, practically all aluminum or aluminum hydride in the mixture transformed into aluminum oxide

Research into vertical axial elements in seasonally frozen grounds

The paper considers the research into the work of vertical axial elements in seasonally frozen grounds under dymanic strain within the frameworks of annual cycle. The authors provide the results of laboratory research into the specific adhesion and dynamic strain impact. They also have developed a structure capable of reducing the impact from frost heaving anf dynamic impact forces during thaw period

Research into vertical axial elements in seasonally frozen grounds

The paper considers the research into the work of vertical axial elements in seasonally frozen grounds under dymanic strain within the frameworks of annual cycle. The authors provide the results of laboratory research into the specific adhesion and dynamic strain impact. They also have developed a structure capable of reducing the impact from frost heaving anf dynamic impact forces during thaw period

Synthesis of Iron Aluminates and a New Modification of Alumina at Impact of Explosive

Synthesis of new high-strength superdispersed materials by use of detonation and shock waves is a developing branch of manufacture. Diamond, metal oxides, nitrides, and many other substances are produced and find industrial application. The objective of current work was the method of synthesis of iron aluminates and a new modification of alumina. For the synthesis initiation of explosion of aluminized composite explosive by impact was firstly used

Hydrogen and carbon monoxide production by chemical looping over iron-aluminium oxides

H-2 and CO production from H2O and CO2 is investigated experimentally using a two-step chemical looping process based on the redox cycles of iron-alumina mixed oxides. The reduction of Fe3O4 in the first endothermic step is followed by the splitting of CO2 or H2O in a second exothermic step. The iron-aluminum oxides are more reactive with H2O than with CO2 in the range 650-750 degrees C. Insitu XRD shows that deactivation results from different processes: iron oxide sintering and the formation of spinel (FeAl2O4) with a lower oxygen-storage capacity. However, FeAl2O4 assumes the role of Al2O3 and mitigates the iron oxide sintering. Deactivation at 650 degrees C is governed predominantly by sintering, and the further loss of activity is caused by combined sintering and spinel formation. Spinel formation is more dominant at 750 degrees C. A mixed oxide of Fe2O3 and Al2O3 with a mass ratio of 70:30 was the most active and stable for H2O and CO2 splitting in chemical looping