Question: how much energy does it take to split water into hydrogen and oxygen?
Answer: Re: How much energy is required to split a water molecule into oxygen and hydrogen? Yes, it takes at least as much energy to split water into O2 and H2 as is released when these gases combine to form water. This is about 260 kJ per mole of water or just shy of 5 eV per molecule of water (4 electrons times 1.23 V).