Complete the following reaction given that electric spark was used to make the two gases react:
2H2 + O2 ⇌ ___
2H2O2(steam)
2H2O(steam)
2H2O(solid)
2H2O2(liquid)
2H2 + O2 ⇌ 2H2O(steam)
In the reaction 2H2O2⟶2H2O+O2, the catalyst used is____________.