A novel recoverable 1D core-shell cotton fiber@ZnIn2S4 composite with improved photoactivity for H2 evolution under visible light

The problems of low activity, high cost and difficulty in recycle of photocatalysts limit their practical application. Coupling photocatalyst with abundant and natural organic material is one of feasible strategies to achieve high photoactivity and low cost of photocatalysts. Herein, one-dimensional (1D) cotton fiber@ZnIn 2 S 4 (CF@ZIS)·composites with a novel core-shell structure were synthesized by coupling ZIS with inexpensive and natural abundance CF via a simple one-pot hydrothermal process. The microstructure, crystalline structures, optical properties and electrochemical property of CF@ZIS were investigated. ZIS nanosheets were in-situ attached on the CF surface, obtaining the CF@ZIS core-shell structure. This core-shell structure significantly suppressed the self-assembly of ZIS nanosheets made almost all ZIS nanosheets exposed to visible light, improving the utilization of light and meanwhile affording more reactive sites. The as-synthesized CF@ZIS showed improved photoactivity for efficient hydrogen production under visible-light irradiation. By replacing the half ZIS by cheap CF, the CF@ZIS-50 photocatalyst exhibited the optimal visible-light photocatalytic activity , which is 2 times than pure ZIS in hydrogen production. The enhanced photoactivity of CF@ZIS photocatalyst should be attributed to the uniform in-situ growth of ZIS nanosheets on the CF surface, the reduction of CF, and the intimate interface between ZIS and CF, resulting in the boosted separation and transfer of photogenerated charges. Additionally, due to the fibrous morphology of CF, the CF@ZIS photocatalyst showed excellent recoverability and photostability. This work provides a promising approach for designing highly efficient and low cost photocatalysts by using natural organic materials.