Izvorni znanstveni članak

Kinetics of Heterogeneous and/or Homogeneous Catalytic Decomposition of Hydrogen Peroxide by Some Metal Vanadates and Their Primary Oxide Mixtures

M. M. Girgis ; Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt
R. M. Gabr ; Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt
A. M. El-Awad ; Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt

Sažetak

A study of the kinetics of catalytic decomposition of H2O2 by some metal (M) vanadates and their primary oxide mixtures, where M=Mg, Ca, Ni, Cu and (Cuo.5+Mgo.5) for catalysts (J-V), respectively, reveals that the decomposition reaction is homogeneous for catalysts (/ and IT), whereas for (Iff—V) the early stages of the reaction are mainly heterogeneous. However, whenever the vanadium, nickel or copper ions go into solution, in the form of the peroxo compounds of vanadium(V), they catalyze the reaction homogeneously at relatively low decomposition rates. Significance of the concept of bivalent catalytic centres towards enhancement of the catalyst activity has been established. It was found that the parameter which best characterizes the intrinsic order of catalytic activity is the activation entropy of the reaction and not the activation energy deduced. The activity order of catalysts (I—V) calcined in air at 500, 700 and 1000 °C for 5 hours was found to be IV>V>III>II>I.

Ključne riječi

Hrčak ID:

137333

URI

https://hrcak.srce.hr/137333

Datum izdavanja:

15.10.1991.

Posjeta: 1.020 *