Answer
From the results obtained from the experiment below, a catalyst is needed for the reaction to happen.
The justification for this can be seen in experiments 1, 2, and 4 where the time taken for oxygen gas to be produced was less than 20 seconds in the presence of a catalyst. However in the absence of a catalyst (experiment 3), the reaction proceeds at a very low rate, i.e takes a few months for oxygen gas to be produced.