Highly efficient piezocatalytic degradation of organic dye over few-layer MoS2/carbon sponge composite boosted by mild mechanical stimuli

Piezocatalysis is a burgeoning sustainable technology due to its attractive potential in solving environmental and resource issues with various mechanical energies. Herein, a high-performance freestanding composite piezocatalyst was synthesized by combining few-layer MoS2 nanosheets with highly porous flexible carbonaceous matirx derived from melamine sponge (CMS), which can greatly harvest mild mechanical energies to trigger off piezoelectric effect for efficient dye degradation. Under mechanical stirring, the developed MoS2/CMS showed distinguished piezocatalytic degradation efficiency (99.8% within 10 min) for Rhodamine B (Rh B) dye solution. Besides, as a brick-shaped piezo-active platform, the MoS2/CMS is easy to be recycled and can remain excellent stability with over 90% degradation rate after 7 cycles of repeated catalytic reactions. To investigate its practical application potential, the MoS2/CMS was mounted in the pipeline of a homemade circulatory system, which was completely decolored 2.0 L Rh B aqueous solution after 2 h under a circulating flow of 30 mL min-1. Overall, this work presents an efficient and extensible strategy for construction of high-performance piezocatalytic materials with not only a desired integrated structure to produce sensitive deformations under mild mechanical stimuli, but also a freestanding form with excellent recyclability to alleviate secondary pollution. This research would provide viable guidance for promoting piezoelectric materials towards practical applications for wastewater decontamination.