LAUSR

Abstract Photoelectrochemical (PEC) water splitting based on silicon (Si) is very promising because of its broad visible light absorption, earth abundance, and high carrier mobility. However, the commercial application is hindered by the poor stability and sluggish oxygen evolution reaction (OER) dynamics in electrolytes. Thanks to the non-noble bimetallic NiMoO 4 nanosheet and atomic layer deposited TiO 2 ultrathin film, we report a highly efficient and stable photoanode made of three-dimensional NiMoO 4 nanosheet/TiO 2 film/Si nanowire arrays. The NiMoO 4 /TiO 2 /Si composite PEC cell delivered a photocurrent density as high as 8.7 mA/cm 2 under 1 Sun illumination, which is 27 times higher than that of pristine TiO 2 coated Si nanowires. Its onset potential was shifted toward the negative potential of 90 mV. The improved performance resulted from the synergistic effects of the favourable light trapping ability and the superior interface charge transfer related to the robust OER activity of NiMoO 4 nanosheets.