Comparative Study on the Catalytic Performance of Metal Oxide Catalysts for Decomposition of Hydrogen Peroxide

Commercial CuO and ZnO powders were analyzed for their catalytic activity under different experimental conditions. The mentioned catalysts were characterized by scanning electron microscope, X-ray diffractometery, Fourier transform infrared spectrometry and BET surface area. The decomposition of hydrogen peroxide was studied in the presence of commercial CuO and ZnO under different experimental conditions. Effect of pH on the decomposition reaction was used to evaluate the mechanism of the decomposition reaction. Surface negative sites were responsible for the decomposition of hydrogen peroxide. Rate constants were calculated for the decomposition reactions in pH and temperature ranges of 9-13 and 30-70 degrees C, respectively. The observed increase in rate constants with increase in pH and temperature was attributed to the increase in surface negativity of both the solid catalysts. The high surface charge negativity (low PZC) and high surface area of CuO were the dominant factors for the better catalytic activity of the solid as compared to ZnO. The comparative study of these solids clearly demonstrate the higher catalytic activity at a given pH and temperature. Activation energies for the decomposition reaction of hydrogen peroxide on the surfaces of CuO and ZnO estimated from the Arrhenius plots were 57 KJ.mol(-1) and 67 KJ.mol(-1), respectively.