Vertically aligned ZnO–Au@CdS core–shell nanorod arrays as an all-solid-state vectorial Z-scheme system for photocatalytic application

Abstract

The development of high-performance artificial photosynthesis systems is central to taking advantage of solar energy to alleviate the environmental and energy crises. Integrating different functional materials ingeniously into an oriented nanoarchitecture holds great promise for constructing more efficient photocatalytic systems with additional structure-directing merits. Here we report an all-solid-state vectorial Z-scheme photosynthetic system composed of vertically aligned ZnO–Au@CdS core–shell nanorod arrays prepared via a heteroepitaxial growth process. Resulting from the synergistic effects of the three functional components integrated in this nanoarray structured system, the photocatalytic efficiency of the optimal ternary ZnO–Au@CdS hybrid is ca. 79 and 28 times higher than that of ZnO and ZnO–Au counterparts, respectively, toward selective reduction of aromatic nitro compounds in water under simulated sunlight irradiation, and even 1.5 times as high as that of the direct Z-scheme featured ZnO@CdS system due to the effective vectorial Z-scheme electron transfer process. Furthermore, the ZnO–Au@CdS nanorod arrays with a film structure are readily recycled and highly stable under the present reaction conditions. This work demonstrates a paradigm for constructing an all-solid-state Z-scheme artificial photosynthetic system favoring enhanced light harvesting, efficient charge separation and transfer, easy recycling and good photostability toward solar energy conversion.