Unified surface modification by double heterojunction of MoS2 nanosheets and BiVO4 nanoparticles to enhance the photoelectrochemical water splitting of hematite photoanode

•α-Fe2O3/BiVO4/MoS2 photoanode was prepared through low-cost methods.•α-Fe2O3 heterojunction with BiVO4 and MoS2 greatly improved the PEC performance.•The multi heterojunction increase the efficiently of the charge separation and injection.•α-Fe2O3/BVO/MoS2 generated 46.5 μmol cm−2 of H2 and 22.3 μmol cm−2 of O2 after 2 h. [Display omitted] Metal oxide semiconductors are among the most promising photoelectrode materials for solar water splitting, mainly due to their robustness in aqueous solutions. In this work, a multi heterojunction with metal oxides is fabricated to enhance the photoelectrochemical (PEC) water splitting through unified surface modification. The two-dimensional MoS2 nanosheets are synthesized through the liquid-phase exfoliation (LPE) process. The characteristics of the MoS2 nanosheets for improving light harvest and charge separation, including thickness, number of layers, and concentration, are all estimated using the proper techniques. The best photocurrent density of the α-Fe2O3/BiVO4/MoS2 at 1.23 V vs. RHE under 100 mW/cm2 (AM 1.5) illumination that was identified around 15 times greater than that of the α-Fe2O3 photoanode. The α-Fe2O3/BiVO4/MoS2 electrode shows the highest donor concentration value (4.36E+26 m3) with the lowest flat band potential (0.15 V) among all the prepared electrodes. Furthermore, the obtained hydrogen and oxygen production in 2 h irradiation for α-Fe2O3/BiVO4/MoS2 is 46.5 and 22.3 μmol cm−2, respectively.