The decomposition proceeds through a sequence of redox reactions with catalyst in different oxidation states. ZnO is not redox active. PbO2 works as a stoichiometric oxidant PbO2 + H2O2 -> PbO + O2 + H2O

Manganese dioxide (MnO2), lead dioxide (PbO2), and zinc oxide (ZnO) are common catalysts used for the decomposition of hydrogen peroxide (H2O2).

The mechanism of action for these catalysts involves the following steps:

PbO2 increases the reaction rate the most among these catalysts due to its high catalytic activity. The high catalytic activity of PbO2 is due to its high surface area, which provides more active sites for the decomposition of H2O2. PbO2 also has a unique crystal structure that allows it to easily exchange electrons with H2O2, promoting the reaction rate.

Additionally, PbO2 is a strong oxidizing agent and can react with the intermediates produced during H2O2 decomposition, preventing them from recombining and slowing down the reaction. This effect, known as the "scavenging effect," also contributes to PbO2's high catalytic activity.

In summary, PbO2 is a highly effective catalyst for H2O2 decomposition due to its high surface area, unique crystal structure, and scavenging effect.

Dear Qasim Qayyum Kashif , have you ever read about pKa? What is the second pKa of H2O2? The mechanism you have suggested for H2O2 decomposition is wrong without any doubt. If you teach the people (e.g. by answering questions), you should be an expert or at least have basic knowledge in the area.

The mechanism of H2O2 decomposition is very well studied and described in many text books.

I apologize for a very straightforward language. I'm tired to read answers based on insufficient knowledge.

Thank you Qasim and Yurii,

I already read in the literature the importance of the different oxydation states in catalysing H2O2 decomposition. Although ZnO is not redox active, it did catalyse the decomposition in the lab. We compoared the three of them and the fastest was PbO2. I already read about the mechanism proposed by Qasim and I am desperately looking for a reference that I can use. Do you have anything regarding this ?

Dear Suha Tannous , Ask Qasim about his mechanism. I clearly stated that this is a wrong mechanism. What is the TurnOver Number (TON) for the ZnO catalyzed reaction?