Hierarchically ZnIn₂S₄ nanosheet-constructed microwire arrays: template-free synthesis and excellent photocatalytic performances

Abstract

Hierarchically ZnIn₂S₄ nanosheet-constructed microwire arrays (NCMAs) on a zinc substrate have been synthesized for the first time through a one-step solvothermal method without using any template or surfactant. The as-synthesized ZnIn₂S₄ microwires are constructed by vertical nanosheets preferentially exposing (006) facets, which are about 1-5 μm in diameters and larger than 10 μm in average length. Experimental results demonstrate that the hierarchically ZnIn₂S₄ NCMAs are converted from intermediate components of single crystalline indium nanowires, which are generated along the direction of (101) planes by a displacement reaction between Zn and In³⁺ during the initial synthesis process. This conversion of indium nanowires to hierarchically ZnIn₂S₄ NCMAs has been explained by a novel corrosion-exchange-self-assembly mechanism, which might indicate a novel strategy for preparing other ternary sulphide nano-microwire arrays. The prepared ZnIn₂S₄ NCMAs are used as photocatalysts, demonstrating effective photocatalytic degradation activity for diverse organic pollutants including different dyes, tetracycline and 2,4,6-tribromophenol (2,4,6-TBP). This efficient photocatalytic activity is ascribed to the strong absorption of ZnIn₂S₄ NCMAs in a wide range from ultraviolet to visible light as well as the preferentially exposed (006) facets of ZnIn₂S₄ nanosheets.