In this study, ZnO–Sn2S3 core–shell nanorod heterostructures were synthesized by sputtering Sn2S3 shell layers onto ZnO rods. The Sn2S3 shell layers consisted of sheet-like crystallites. A structural analysis revealed that the ZnO–Sn2S3 core–shell nanorod heterostructures were highly crystalline. In comparison with ZnO nanorods, the ZnO–Sn2S3 nanorods exhibited a broadened optical absorption edge that extended to the visible light region. The ZnO–Sn2S3 nanorods exhibited substantial visible photodegradation efficiency of methylene blue organic dyes and high photoelectrochemical performance under light illumination. The unique three-dimensional sheet-like Sn2S3 crystallites resulted in the high light-harvesting efficiency of the nanorod heterostructures. Moreover, the efficient spatial separation of photoexcited carriers, attributable to the band alignment between ZnO and Sn2S3, accounted for the superior photocatalytic and photoelectrochemical properties of the ZnO–Sn2S3 core–shell nanorod heterostructures.

TiO2–CdO composite rods were synthesized through a hydrothermal method and sputtering thin-film deposition. The hydrothermally derived TiO2 rods exhibited a rectangular cross-sectional crystal feature with a smooth surface, and the as-synthesized CdO thin film exhibited a rounded granular surface feature. Structural analyses revealed that the CdO thin film sputtered onto the surfaces of the TiO2 rods formed a discontinuous shell layer comprising many island-like CdO crystallites. The TiO2–CdO composite rods were highly crystalline, and their surfaces were rugged. A comparison of the NO2 gas-sensing properties of the CdO thin film, TiO2 rods, and TiO2–CdO composite rods revealed that the composite rods exhibited superior gas-sensing responses to NO2 gas than did the CdO thin film and TiO2 rods, which can be attributed to the microstructural differences and the formation of heterojunctions between the TiO2 core and CdO crystallites.

ZnO-ZnS core-shell nanorods are synthesized by combining the hydrothermal method and vacuum sputtering. The core-shell nanorods with variable ZnS shell thickness (7–46 nm) are synthesized by varying ZnS sputtering duration. Structural analyses demonstrated that the as-grown ZnS shell layers are well crystallized with preferring growth direction of ZnS (002). The sputtering-assisted synthesized ZnO-ZnS core-shell nanorods are in a wurtzite structure. Moreover, photoluminance spectral analysis indicated that the introduction of a ZnS shell layer improved the photoexcited electron and hole separation efficiency of the ZnO nanorods. A strong correlation between effective charge separation and the shell thickness aids the photocatalytic behavior of the nanorods and improves their photoresponsive nature. The results of comparative degradation efficiency toward methylene blue showed that the ZnO-ZnS nanorods with the shell thickness of approximately 17 nm have the highest photocatalytic performance than the ZnO-ZnS nanorods with other shell layer thicknesses. The highly reusable catalytic efficiency and superior photocatalytic performance of the ZnO-ZnS nanorods with 17 nm-thick ZnS shell layer supports their potential for environmental applications.

TiO2–ZnS core–shell composite nanorods were synthesized by using ZnO as a sacrificial shell layer in a hydrothermal reaction.