3D Cathodes of Cupric Oxide Nanosheets Coated onto Macroporous Antimony-Doped Tin Oxide for Photoelectrochemical Water Splitting.

Cupric oxide (CuO), a narrow-bandgap semiconductor, has a band alignment that makes it an ideal photocathode for the renewable production of solar fuels. However, the photoelectrochemical performance of CuO is limited by its poor conductivity and short electron diffusion lengths. Herein, a three-dimensional (3D) architecture consisting of CuO nanosheets supported onto transparent conducting macroporous antimony-doped tin oxide (mpATO@CuONSs) is designed as an excellent photocathode for promoting the hydrogen evolution reaction (HER). Owing to the 3D structure affording superior light-harvesting characteristics, large contact areas with the electrolyte, and highly conductive pathways for separation and transport of charge carriers, the mpATO@CuONSs photocathode produces an impressively high photocurrent density of -4.6 mA cm-2 at 0 V versus the reversible hydrogen electrode (RHE), which is much higher than that of the CuONSs array onto planar FTO glass (-1.9 mA cm-2 ).