LAUSR

Abstract This paper demonstrates the design and fabrication of three-dimensional (3D) hexagonally ordered microbowl arrays (MBAs) decorated with CuInS2 nanosheets for enhanced photoelectrochemical (PEC) performance. The 3D MBAs are fabricated by a micro-fabrication technique. The ultrathin CuInS2 nanosheets are grown on the 3D electrodes by solvothermal transformation of Cu film. The photocurrent density of 3D photocathode (CuInS2@MBAs) is about two times higher than that of the planar counterpart (CuInS2@Planar). The improved PEC performance can be ascribed to the elevated light trapping ability and the increased surface area for loading photocatalysts. In addition, CdS quantum dots as cocatalysts are modified onto the CuInS2 nanosheets to further enhance the PEC activity because the formed p-n heterojunction can accelerate the separation of photogenerated carriers. As a result, the 3D photocathode of CuInS2/CdS@MBAs shows an optimal incident photon to current efficiency of 10% at the wavelength of 400 nm. It is believed that this work can be generalized to design other hierarchical 3D photoelectrodes for improved solar water splitting.