P-Type CuBi₂O₄: An easily accessible photocathodic material for high-efficiency water splitting

In view of the disadvantages of the conventional photocathodic materials, we focus on exploiting new candidates for a high-efficiency photoelectrochemical (PEC) system. Herein, we report on the fabrication of CuBi₂O₄ (CBO) films on FTO (fluorine doped tin oxide) and FTO/Au substrates, respectively, through the electrochemical deposition approach. It was observed that the presence of a Au thin layer could help to improve the crystal quality of the grown CBO films, promote the separation of photo-generated charges in the corresponding material and reduce the resistance of the system. In comparison with the FTO/CBO, the FTO/Au/CBO photocathode presents a remarkable improvement in the photocurrent, from -0.23 mA cm^-2 to -0.50 mA cm^-2 at 0.1 V vs. RHE. After optimizing the PEC system by depositing Pt nanoparticles on the CBO films, the plateau photocurrent was further amplified to -1.24 mA cm^-2. These data indicate an attractive p-type material in photoelectrochemistry, without concern for the corrosion problem in aqueous electrolytes.