There are two vertical states 1 and 2 for ZnO trimer adsorbed on graphene. Hydrolysis of water on ZnO trimer in the vertical 1 state of graphene C 30 (ZnO) 3 does not proceed beyond the first water molecule when the hydrated structures effortlessly reorganize to the final stable hydrolyzed structures C 30 O 3 ZnO 2 (OH) 2 with negative energies (-167kcal/mol in the singlet and -30.4 kcal/mole in the triplet state)and curve crossing of the singlet and triplet states as displayed in Figure and Table . In contrast to this, successive hydration and hydrolysis of two water molecules in the vertical state 2 of the zinc oxide trimer on graphene as shown in the figure and table 8 occurs readily with low activation energies for hydrolysis 0,9 and 1.2 kcal/mol for the first hydrolysis and 26.3 and 2.7 kcal/mol respectively for the second in the triplet and singlet states, without curve crossing and the energy gap between triplet and singlet states is reduced from -45.5kcal/mol in the initial to -31 kcal /mol in the final hydrolyzed product. The trend of low activation energies for the first and second hydrolysis of water molecules continues for the G01 to G05 models even along different pathways although the structural intermediates may not be the same. This is illustrated in Figures 12 to 20 for the mechanistic pathways and the corresponding Tables 9 to 12 for the associated energies for hydration and hydrolysis. The real bottlenecks begin with the next few steps of water splitting. and 13. The temperature is 298K. Table shows the relative energies and energy changes of hydration and hydrolysis reaction of bare (ZnO) 3 and (ZnO) 3 on graphene and GO systems with two water molecules.