Open AccessCatalytic Decomposition of H2O2over Pure and Li2O-Doped Co3O4Solids
Author(s) -
G.A. El-Shobaky,
Nagi R.E. Radwan,
F. M. Radwan
Publication year - 1998
Publication title -
adsorption science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.682
H-Index - 36
eISSN - 2048-4038
pISSN - 0263-6174
DOI - 10.1177/026361749801600906
Subject(s) - dopant , chemistry , calcination , doping , bet theory , catalysis , oxide , inorganic chemistry , thermal decomposition , adsorption , thermal treatment , lithium oxide , lithium nitrate , analytical chemistry (journal) , lithium carbonate , decomposition , mineralogy , ion , materials science , electrochemistry , optoelectronics , organic chemistry , electrode , ionic bonding , lithium vanadium phosphate battery , composite material , biochemistry , chromatography
Pure and doped Co 3 O 4 samples were prepared by the thermal decomposition at 500–900°C of pure and lithium nitrate-treated basic cobalt carbonate. The amounts of dopant added were varied in the range 0.75–6 mol% Li 2 O. The effects of this treatment on the surface and catalytic properties of cobaltic oxide solid were investigated using nitrogen adsorption at −196°C and studies of the decomposition of H 2 O 2 at 30–50°C. The results obtained revealed that Li 2 O doping of Co 3 O 4 followed by heat treatment at 500°C and 600°C resulted in a progressive increase in the value of the specific surface area, S BET , to an extent proportional to the amount of dopant present. However, the increase was more pronounced in the case of solid samples calcined at 500°C. This increase in the specific surface areas has been attributed to the fixation of a portion of the dopant ions on the uppermost surface layers of the solid leading to outward growth of the surface lattice. The observed increase in S BET due to Li 2 O doping at 500°C might also result from a narrowing of the pores in the treated solid as a result of the doping process. Lithium oxide doping of cobaltic oxide followed by heat treatment at 700–900°C resulted in a significant decrease in the S BET , V p and r̄ values. Pure and doped solids precalcined at 500°C and 600°C exhibited extremely high catalytic activities which were not much affected by doping with Li 2 O. On the other hand, doping followed by calcination at 700–900°C brought about a considerable and progressive increase in the catalytic activity of the treated solids. This treatment did not modify the activation energy of the catalysed reaction, i.e. doping of Co 3 O 4 solid followed by heating at 700°C and 900°C did not alter the mechanism of the catalytic reaction but increased the concentration of catalytically active constituents taking part in the catalytic process without altering their energetic nature.