Efficient photoelectrochemical water splitting of CaBi6O10 decorated with Cu2O and NiOOH for improved photogenerated carriers

Broadening the light absorption and accelerating the separation of photogenerated electron-hole pairs is of crucial importance for strongly enhancing the photoelectrochemical (PEC) water splitting performances of photoelectrode. In this paper, a novel CaBi₆O₁₀/Cu₂O/NiOOH photoanode for photoelectrochemical water splitting is prepared, where, the NiOOH acts as water oxidation catalyst to accelerate water oxidation taking place in the interfaces between electrode and electrolyte, Cu₂O is chosen to extend the absorption range of the light absorber, enhancing an efficient separation and transfer of the electron-hole pairs. This triple CaBi₆O₁₀/Cu₂O/NiOOH photoanode negatively shifts the onset potential and exhibits an improved photocurrent density 1.89 mA·cm^?2 at 1.23 V vs RHE, which is 1.4 and 4.8 times higher compared to CaBi₆O₁₀/Cu₂O and CaBi₆O₁₀, respectively. More importantly, the CaBi₆O₁₀/Cu₂O/NiOOH electrode shows excellent photoelectrochemical stability in comparison with CaBi₆O₁₀/Cu₂O after 2 h irradiation. The amazing photoelectrochemical performance is due to the broader light absorption spectrum, the improved photogenerated carriers separation, transfer and consumption. The research results demonstrate a promising ternary semiconductor structure, which can improve photoelectrochemical performance effectively. Moreover, these results also imply that the CaBi₆O₁₀/Cu₂O/NiOOH heterojunction structure has a great potential application for photoelectrochemical water splitting systems.