CdS is a promising visible-light responsive photocatalyst. However, the serious photocorrosion limits its application in photocatalysis. Here we report a novel strategy to overcome the disadvantage of CdS photocorrosion by fabricating peroxide decomposing active MnO₂ thin-layer over CdS nanowires (NWs) and assembling oxygen separation artificial gill to remove nascent formed oxygen in the dispersion. In the meantime, the using non-noble metal NiSe quantum dots (QDs) co-catalyst, NiSe/MnO₂-CdS photocatalysts shows excellent photocatalytic over-all water splitting activity and remarkable stability under visible light irradiation without addition of any sacrifice reagent, 455.0 µmol h⁻¹ g⁻¹ of hydrogen evolution reaction (HER) rate and 5.20% of apparent quantum efficiency (AQEs) at 430 nm. Removing nascent formed O₂ from water by artificial gill can prevent the oxygen leading CdS photocorrosion. Photoluminescence spectra and photoelectrochemical measurements indicate that loading NiSe QDs and coating MnO₂ thin-layer can also improve transfer of the photogenerated charges in CdS. MnO₂ thin-layer can decompose formed hydrogen peroxide and enhance water splitting. Our results could potentially provide a new method for designing and fabricating more stable and efficient CdS-based nanocomposite photocatalysts toward versatile solar energy conversion.