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ZnO/Si nanotrees were coated by Ag 2 S and In 2 S 3 nanoparticles. The built-in electric field of the heterojunctions induced electron-hole pair recombination in the conduction band of ZnO and valence bands of other semiconductors at the interfaces, which reduced charge recombination in the interior of the component semiconductors and improved redox ability. • Heterogeneous nanowire arrays were grown resulting in efficient dye photodegradation. • Introduction of quantum dots yielded a quarter resistance and 31-fold photocurrent. • The samples got efficiency of 62% and 55% in visible and UV light with recyclability. • Z-scheme heterojunctions played a critical role in the high photocatalytic activity. Hierarchical heterogeneous ZnO/Si nanowire arrays grown from metal-induced wet etching process on p-type silicon wafer were obtained and have been strategically sensitized by narrow bandgap semiconductors of In 2 S 3 nanosheets and Ag 2 S quantum dots via successive ionic layer adsorption and reaction technique. The photodegradation of methylene blue as catalyzed by the arrays was conducted under visible light and ultraviolet light. By introducing the coating layers, the specimens were found to achieve absorptivity higher than 94% and yield a quarter of the resistance and 31-fold of the photo-current as compared to the primary nanowire arrays. The photodegradation efficiency was improved from 48.9% to 62.0%, and 43.0% to 55.0%, respectively in visible light and ultraviolet light with an enhanced recyclability. Band structure analysis indicated that the coating brought different Z-scheme heterojunctions for efficient photocatalytic performance, while the function could only work in a given spectral range. These results would be helpful to better realize the photocatalytic mechanisms and meanwhile, could be extended to design heterogeneous semiconductor nanomaterials for their potential applications. [ABSTRACT FROM AUTHOR]

• Ag 2 S-sensitized ZnO/SnO 2 core-shell nanowire arrays were successfully synthesized. • The absorptivity of the sample was larger than 95% in visible and UV range. • The photocurrent response of the sample reached 53.6-fold of the ZnO NW arrays. • The catalytic efficiency got 71.61% and 57.58% respectively in visible and UV range. • Mechanism of the effective photocatalysis was explored. Ag 2 S quantum dots-sensitized ZnO/SnO 2 core-shell nanowire arrays were successfully synthesized layer by layer through hydrothermal growth, atomic layer deposition, and successive ionic layer adsorption and reaction process. By introducing the two-layer semiconductors, the bandgap of ZnO component in the arrays was slightly modulated, while the light absorption was obviously improved with an absorptivity higher than 95% in visible and ultraviolet range. In contrast to the ZnO NW arrays, the photocurrent response of the ZnO/SnO 2 /Ag 2 S NW arrays for the visible light was improved from 0.42 μA to 22.5 μA, and the photodegradation efficiency of methylene blue was increased from 45.24% to 71.61%, and 42.61% to 57.58%, respectively in visible light and ultraviolet light. Band structure analysis indicated that the coating layer brought different staggered gaps and suitable band alignment for efficient photocatalytic performance, which could be extended to design heterogeneous semiconductor nanomaterials for their potential applications. [ABSTRACT FROM AUTHOR]