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The bare surface of BiVO₄ photoanode usually suffers from extremely low interfacial charge transfer efficiency which leads to a significantly suppressed photoelectrochemical water splitting performance. Various strategies, including surface modification and the loading of co-catalysts, facilitate the interface charge transfer process in BiVO₄. In this study, we demonstrate that CoS₂ synthesized from the hydrothermal method can be used as a high-efficient co-catalyst to sufficiently improve the interface charge transfer efficiency in BiVO₄. The photoelectrochemical water splitting performance of BiVO₄ was significantly improved after CoS₂ surface modification. The BiVO₄/CoS₂ photoanode achieved an excellent photocurrent density of 5.2 mA/cm² at 1.23 V versus RHE under AM 1.5 G illumination, corresponding to a 3.7 times enhancement in photocurrent compared with bare BiVO₄. The onset potential of the BiVO₄/CoS₂ photoanode was also negatively shifted by 210 mV. The followed systematic combined optical and electrochemical characterization results reveal that the interfacial charge transfer efficiency of BiVO₄ was largely improved from less than 20% to more than 70% due tor CoS₂ surface modification. The further surface carrier dynamics study performed using an intensity modulated photocurrent spectroscopy displayed a 6–10 times suppression in surface recombination rate constants for CoS₂ modified BiVO₄, which suggests that the key reason for the improved interfacial charge transfer efficiency possibly originates from the passivated surface states due to the coating of CoS₂.