Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} The decomposition of hydrogen peroxide was studied in the presence of monodispersed nickel oxide powders, obtained from the nickel basic carbonate at the calcinations rates of 5, 10, 15, and 20 oC/min and on commercial nickel oxide powders. Effect of pH on the decomposition reaction was used to evaluate the mechanism of the decomposition reaction. It was observed that only the surface negative sites were responsible for the observed decomposition of hydrogen peroxide. Rates constants were calculated for the decomposition reaction in the temperature range of 35-50 oC and the activation energies were estimated from the Arrhenius plots for all the synthetic and commercial samples of nickel oxides.