Subject: Is there a negative catalyst for manganese dioxide ?

I am carrying out an investigation on the rate of decomposition of H2O2. 
During the investigation i will allow the catalysed decomposition of H2O2 
to occur and extract samples of the partially decomposed H2O2 at different 
time intervals. When the samples are removed i need a way to stop the 
catalyzed decomposition H2O2 so that the amount of remaining H2O2 can be 
analysed.

For the catalyzed decomposition of H2O2 with yeast as the catalyst, the 
inhibitor i will use is ammonium molbdate solution. I need to find a 
suitable inhibitor for the catalytic action of MnO2 so that the effect of 
organic and inorganic catalysts can be compared. 

Re: Is there a negative catalyst for manganese dioxide ?