The Energy Potential of Water July 2015
Hydrogen, one of the most abundant elements on earth, is a powerful source of energy that could one day eliminate our reliance on fossil fuels. However, because it is only found in compound form, extracting it from water requires electrolysis, a highly energy intensive process with an environmental impact.
A more sustainable method of extracting hydrogen is photocatalytic water splitting, which relies on solar energy to split water into its constituent elements – hydrogen and oxygen. But even this route is limited in performance, mainly due to the poor absorption of visible light. In fact, most catalysts cannot absorb and utilize the visible range of sunlight, resulting in much less than 10 percent solar-to-fuel efficiency, which is the threshold for the cost effectiveness of photocatalytic technology. Moreover, the existing means of solar water splitting is about 10 times more expensive than the cost of hydrogen production from fossil fuels.