Standardisation means accurately determining the concentration. Potassium manganate(VII) solid is not a primary standard. This means that, for various reasons, you cannot just weigh it out, make up a solution and assume that the concentration will be what you would expect. Therefore you have to make up a 'standard' solution of a reducing agent, titrate it against the KMnO4 and calculate the concentration of the KMnO4 from the titre. A suitable reducing agent would be sodium ethanedioate (a.k.a. oxalate) which is a primary standard. Regarding the project as a whole, you cannot use KMnO4 as a 'catalyst' for the specified reaction as KMnO4 will actually oxidise H2O2 according to the half equation: H2O2 --> 2H+ + O2 + 2e- I wonder whether you are confusing KMnO4 with MnO2 which is often used as a catalyst for the reaction you quote.