Lattice origin of few-layer edge-on MoS2@TiO2 octahedral clusters for piezoelectric enhancement

Abstract

Imaging the lattice origin of few-layer edge-on MoS2/TiO2 heterostructure at different growth stages could provide direct information for understanding the mechanism of its enhanced piezoelectric property. Via modifying the substrate surface to grow anatase TiO2 nanoparticles with truncated octahedron structure, few-layer MoS2 was exquisitely grown along the {101} basal planes of TiO2 by Van der Waals contact, and finally form an edge-on structure at the top edge of TiO2 nanoparticles due to steric hindrance. The vertical growth of few-layer MoS2 on the TiO2 surface endows not only better electronic contact between MoS2 and TiO2 substrate for fast electrons transfer but also high structure stability of piezoelectric properties. The piezocatalytic degradation ability is enhanced with the increase of hydrothermal reaction time, and the MoS2/TiO2-24 h sample exhibits the highest piezocatalytic activity under dark condition which demonstrates a high removal efficiency of 96.0% Rhodamine B within 60 min. This study establishes a relationship between the piezoelectric property of few-layer edge-on MoS2/TiO2 heterostructure and its growth mechanisms, and sheds light on the rational design of electric contact between transition metal dichalcogenide and semiconductor with specific crystal plane which is significant to the improvement of carrier separation and transport.