N,Cu-Codoped Carbon Nanosheet/Au/CuBi₂O₄ Photocathodes for Efficient Photoelectrochemical Water Splitting

Abstract

In this paper, we successfully fabricated CuBi2O4 and nitrogen,cuprum-codoped carbon nanosheet (N,Cu-C) heterostructure connected by Au nanoparticles, which was applied in photoelectrochemical (PEC) water splitting for the first time. The Au nanoparticle in situ decoration on the material surface was carried out by simple photoreduction. Owing to the plasmon resonance effect and low charge transfer resistance of Au nanoparticles, CuBi2O4/Au/N,Cu-C hybrids exhibited enhanced photo current compared with traditional CuBi2O4 and CuBi2O4/N,Cu-C. Typically, the as-prepared photoelectrode displayed an optimal photoelectric conversion (0.17%, at 0.4 V vs RHE) and PEC photocurrent (0.31 mA cm(-2), at 100 mW cm(-2) and 0.5 V vs RHE) that is about 5 times that of pure CuBi2O4. The enhanced PEC water splitting ability can be mainly attributed to the N,Cu-codoped carbon nanosheets as the passivation layer and Au nanoparticles as an electron relay for electron transport and a plasmonic photosensitizer for increased light absorption.