In-situ derived hierarchical ZnO/Zn-C nanofiber with high photocatalytic activity and recyclability under solar light

Abstract

Carbon-doping in the crystal structure of ZnO has been proven to promote visible light induced photocatalytic activity. However, experimental procedures reported in literature to date for the fabrication of C-doped ZnO generally follow cumbersome steps and environmentally unfriendly techniques. In this study, we present a simple, relatively “green” and adaptable two-step synthesis using electrospinning and calcination techniques for the fabrication of C-doped ZnO nanofiber photocatalyst. Extensive characterization of the as-prepared nanofiber photocatalysts was made by XRD, XPS, FE-SEM, FE-TEM, EDS, N 2 adsorption, TGA, FT-IR, LSV and EIS analysis techniques. Depending on the calcination temperature, the crystallinity of the ZnO nanoparticles and amount of the polymer matrix on the nanofibers differ, which in turn tune the photocatalytic performance. Crystal structure and chemical state analysis confirm the C-doping and introduction of new energy level (Zn C) in the ZnO crystal. Photoelectrochemical analysis proved the enhanced photocurrent response and reduced charge carrier recombination in the C-doped ZnO. The as-prepared photocatalyst exhibited high degradation efficiency (96% in 30 min) for the solar light mediated photodegradation of Methylene blue dye. The fibrous nature of the photocatalyst, with Carbon matrix wrapping around it, alleviates the recovery of the as-prepared photocatalyst from the reaction mixture and ensures its recyclability and protection against photo-corrosion. Considering the scalability and easiness of the experimental procedure, together with the enhanced photocatalytic activity and recyclability of the photocatalyst prepared, we believe this study open doors for the fabrication of high-performance photocatalytic materials at large scale. • C-doped ZnO nanofiber was successfully fabricated through two step synthesis. • The photocatalytic performance was tuned based on the calcination temperature. • Formation of Zn-C energy level enables bandgap excitation under visible light. • As compared to commercial ZnO, C-ZnO-450 exhibited 4 folds higher photocurrent. • Photo-corrosion and catalyst recovery issues of ZnO were also adequately addressed.