In-situ synthesis of 3-D hierarchical ZnFe2O4 modified Cu2S snowflakes: Exploring their bifunctionality in selective photocatalytic reduction of nitroarenes and methyl orange degradation

Designing hierarchical photocatalysts holds a great promise in the future due to their potential to solve energy and environmental problems. Herein, we report the design of intriguing Cu2S snowflakes doped with ZnFe2O4 nanospheres through the in-situ self-assembly method. This effective heterojunction is constructed by controlling the amount of Cu2S dopant during the formation of the photocatalyst which leads to efficient electron-hole separation and fast photo-response. Besides, the multidimensional structure of the catalyst enhances its light harvesting properties, provides high surface area and abundant active sites that accelerate the reaction kinetics. The obtained ZnFe2O4/Cu2S composite not only exhibited an excellent photocatalytic reduction of nitrobenzene with 98 % yield (similar to 35 % more than pristine Cu2S and ZnFe2O4) but also degraded methyl orange and methylene blue dyes proficiently (94.3 % and 86 %) upon visible light illumination. Further, GC-MS studies were performed to identify the intermediates formed and deduce the mechanistic pathway for both processes. Another key feature that made the fabricated photocatalyst economical and sustainable is its easier magnetic retrievability from the reaction mixture along with a good reusability for several runs without any significant loss in its activity.