Shorter wave, and thus more energetic, photons from ultraviolet and visible light can accomplish the task.But semiconductors capable of splitting water are far more expensive than standard silicon solar panels, making that option too costly.So, in the new study, researchers led by Zetian Mi, a chemist at the University of Michigan, Ann Arbor, tweaked their photocatalytic equipment.“This is quite an accomplishment,” adds Peidong Yang, a chemist at the University of California, Berkeley, whose team helped pioneer photocatalytic water splitting 20 years ago but who was not involved with the current work.Todd Deutsch, a water-splitting expert at the National Renewable Energy Laboratory, adds that the efficiency is now within striking distance of the 10% target likely needed to make these devices commercially viable."