NiCo3-LDH catalysts decorated with p-n heterojunction CuCoO2/BiVO4 photoanodes for enhanced photoelectrochemical water oxidation

Due to the suitable bandgap and valence band for photoelectrochemical (PEC) water oxidation, BiVO4 has been regarded as a promising photoanode material. However, poor charge-separation and -transport behavior as well as sluggish surface oxygen evolution reaction (OER) kinetics caused the BiVO4 photoanode for water splitting to be significantly lower than its theoretical value. In this study, the synergistic effect of constructing an n-BiVO4/p-CuCoO2 heterojunction and NiCo3-LDH as an OER cocatalyst was designed to enhance the PEC performance of BiVO4 photoanode. The resultant BiVO4/CuCoO2/NiCo3-LDH demonstrates a maximum photocurrent density of 6.95 mA/cm2 at 1.8 V vs. RHE, which is approximately 24.8 times that of BiVO4 (0.28 mA/cm2) and 5.5 times that of BiVO4/CuCoO2 (1.27 mA/cm2) with good stability (70 % remained after 2 h of operation). This work broadens the construction strategy of photoanode heterojunctions to enhance PEC performance. [Display omitted] •Combination of p-n junction and OER cocatalysts to enhance PEC performance.•Modification of BiVO4 with CuCoO2 and NiCO3-LDH cocatalyst to enhance the PEC performance.•Optimum molar ratio of Ni and Co was investigated to enhance the OER catalytic performance of NiCo3-LDH.•Photocurrent density of BiVO4/CuCoO2/NiCo3-LDH is about 24.8 times compared with that of BiVO4.•Simple routes have been adopted for the fabrication of BiVO4/CuCoO2/NiCo3-LDH photoanodes.