You can use the H2O2 vs potassium permanganate titration method to measure catalase activity.
I found a protocol from researchgate. I do not want to share it here, because it is not mine. Bu you can download it, just search the name (CatalaseActivity).
We have also used H2O2 method described by Aebi, 1984 (Aebi H. 1984. Catalase in vitro. Meth Enzymol.105:121–126). You can see our article attached herewith.
Dear, Catalase activity may be measured quantitatively by the method of von Euler and Josephson by allowing the enzyme solution to react with hydrogen peroxide for varying periods of time and measuring the excess peroxide remaining by titration with potassium permanganate.