Luo, JingshanIm, Jeong-HyeokMayer, Matthew ThomasSchreier, MarcelNazeeruddin, Mohammad KhajaPark, Nam-GyuTilley, S. DavidFan, Hong JinGraetzel, Michael2014-10-232014-10-232014-10-23201410.1126/science.1258307https://infoscience.epfl.ch/handle/20.500.14299/107644WOS:000342164500040Although sunlight-driven water splitting is a promising route to sustainable hydrogen fuel production, widespread implementation is hampered by the expense of the necessary photovoltaic and photoelectrochemical apparatus. Here, we describe a highly efficient and low-cost water-splitting cell combining a state-of-the-art solution-processed perovskite tandem solar cell and a bifunctional Earth-abundant catalyst. The catalyst electrode, a NiFe layered double hydroxide, exhibits high activity toward both the oxygen and hydrogen evolution reactions in alkaline electrolyte. The combination of the two yields a water-splitting photocurrent density of around 10 milliamperes per square centimeter, corresponding to a solar-to-hydrogen efficiency of 12.3%. Currently, the perovskite instability limits the cell lifetime.text::journal::journal article::research article