Kinetics, Mechanism, and Activation Energy of H₂O₂ Decomposition on the Surface of ZrO₂

The kinetics, mechanism, and activation energy of H 2 O 2 decomposition in ZrO 2 particle suspensions were studied. The obtained first-order and second-order rate constants for the decomposition of H 2 O 2 in the presence of ZrO 2 at T = 298.15 K produced the values k 1 = (6.15 ± 0.04) × 10 −5 s −1 and k 2 = (2.39 ± 0.09) × 10 −10 m·s −1, respectively. The dependency of the reaction first-order rate constant with temperature was studied; consequently, the activation energy for the reaction was obtained in the temperature interval 294.15−353.15 K having yielded the value E a = 33 ± 1.0 kJ·mol −1 . The dependency of the zeroth-order reaction rate constant with pH was investigated and discussed. A mechanistic study encompassing the investigation of the dynamics of formation of hydroxyl radicals during the course of the reaction was performed. A version of the modified Hantzsch method was applied for this purpose, and it was verified that the dynamics of formation of hydroxyl radicals during the reaction are in good agreement with the proposed reaction mechanism.