The catalytic activity has been investigated in 2D materials, and the unique structural and electronic properties contribute to their success in conventional heterogeneous catalysis. Heterojunction-based piezocatalysis has attracted increasing attention due to the band-structure engineering and the enhanced charge carrier separation by prominent piezoelectric effect. However, the piezocatalytic behavior of van der Waals (vdW) heterostructures is still unknown, and the finite active sites, catalyst poisoning, and poor conductivity are challenges for developing good piezocatalysts. Herein, a reduced graphene oxide (rGO)-MoS2 heterostructure is rationally designed to tackle these challenges. The heterostructure shows a record-high piezocatalytic degradation rate of 1.40 × 102 L mol-1 s-1 , which is 7.86 times higher than MoS2 nanosheets. Piezoresponse force microscope measurements and density functional theory calculation reveal that the coupling between semiconductive and piezoelectric properties in the vdW heterojunction is vital to break the metallic state screening effect at the MoS2 edge for keeping the piezoelectric potential. The dynamic charges generated by MoS2 and the fast charge transfer in rGO activate and maintain catalytically active sites for pollutant degradation with an ultra-fast rate and good stability. The working mechanism opens new avenues for developing efficient catalysts significant to wastewater treatments and other applications.
Keywords: 2D heterojunction-based piezocatalysis; DFT calculations; active site edges; charge transfer; piezocatalytic mechanism.
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