Study on the Synthesize, Characterization, and Conductive Performance of Nickelzircomolybdnum Heteropoly Acid Salt with Keggin Structure

A novel heteropoly acid salt, Na6[Ni(Mo11ZrO39)]·20H2O, has been synthesized by the means of acidification and adding the reactants into the solution step by step. The heteropoly compound was characterized by elemental analysis, TGA/DSC, infrared spectrum, ultraviolet spectrum, X-ray diffraction, and SEM. Its protonic conduction was measured by the means of the electrochemical impedance spectrum. The results showed that it belongs to the Keggin type, and its conductivity value was 1.23 × 10–2 S/cm at 23°C when the relative humidity was 60%, and the conductivity enhanced with the elevated temperature. Its proton conduction mechanism was in accordance with vehicle mechanism, and the activation energy was 27.82 kJ/mol.

Efficiency of using heteropoly compounds of the type (NH4)2[Co(H2O)4]2[Mo8O27]∙6H2O as catalysts for the production of ethylene

Carrying out heterogeneous acid catalysis with the use of heteropoly compounds has received considerable attention due to the great economic and environmental benefits. In spite of this, its industrial application is limited as there are difficulties in catalyst regeneration (settling) caused by its relatively low thermal stability. The aim of present work was to search and select catalysts related to the class of heteropoly compounds for propane cracking, to test the selectivity of the prosses as well as to discuss possible approaches for solving the problem of catalyst deactivation, that can contribute to achieve stable characteristics of solid heteropoly catalysts. Among these approaches are: the development of new catalysts with high thermal stability, the modification of catalysts to promote coke combustion, the inhibition of coke formation on heteropoly compound catalysts during the process, carrying out the reactions in supercritical media and also the cascade reactions using a multifunctional heteropoly catalyst. The obtained catalyst was also studied by physicochemical methods to get deep knowledge about which features of these compounds influence on the catalytic activity. A highly active and selective catalyst for ammonium octomolybdenocobaltate(II) ammonium (NH4)2[Co(H2O)4]2[Mo8O27]∙6H2O was synthesized for cracking associated petroleum gases. The qualitative, quantitative, and structural composition as well as the specific surface area of the obtained catalyst was established by the methods of X-ray diffraction, X-ray phase and fluorescence analysis. It was revealed that ammonium octomolybdenocobaltate(II) crystallizes in a triclinic syngony with cell parameters: а = 8.6292(9) Å b = 9.4795(10) Å c = 12.2071(13) Å α = 104.326(2)° β = 109.910(2)° γ = 100.820(2)°.

A new electrocatalytic systems based on bisorbents from rice husk

The article studies the synthesis of carbon-based and amorphous silicon dioxide bisorbents. Sorption characteristics of new bases for producing modified systems to use them in electrocatalysis are presented. For preparation of SiO2/C baseas rice husk (RH) was chosen as the raw material. A series of experiments was performed to optimize parameters of the RH carbonization by varying temperature and time of the process. The material obtained from the RH thermal destruction products was modified by the heteropoly compound (NH4)3[Co3O6Mo6O18H6] · nH2O and thermally reduced by hydrogen. The registration of the voltammetric curves was carried out at pH = 6.22 in the background electrolyte of 0.1 M Na2SO4 and pH = 4.45 in 0.1 M KC8H5O4.The potential ranges were -1.2В – 1.2 V and -1.0 V – 0.2 respectively. The mechanism of the electrochemical processes on these materials has been studied. It is shown that the obtained composite electrode materials exhibit electrochemical activity in the investigated potential regions, and they are characterized by the stability of redox properties. The main ways of using the obtained composites are outlined.