MoS2-based multiple surface plasmonic coupling for enhanced surface-enhanced Raman scattering and photoelectrocatalytic performance utilizing the size effect

MoS2-based heterostructures have received increasing attention for not only surface-enhanced Raman scattering (SERS) but also for enhanced photoelectrocatalytic (PEC) performance. This study presents a hydrothermal method for preparing vertical MoS2 nanosheets composed of in situ grown AuNPs with small size and chemically reduced AgNPs with large size to achieve the synergistic enhancement of SERS and PEC properties owing to the size effect of the plasmonic structure. Compared with pristine MoS2 nanosheets and unitary AuNPs or AgNPs composited with MoS2 nanosheets, the ternary heterostructure exhibited the strongest electromagnetic field and surface plasmon coupling, which was confirmed by finite-difference time-domain (FDTD) simulation and absorption spectra. In addition, the experimental results confirmed the outstanding SERS enhancement with an EF of 1.1x10(9), and the most efficient hydrogen evolution reaction (HER) activity with a sensitive photocurrent response, attributing to the multiple surface plasmonic coupling effects of the Au-Ag bimetal and efficient charge-transfer process between MoS2 and the bimetal. That is, it provides a robust method for developing multi-size bimetal-semiconductor complex nanocomposites for high-performance SERS sensors and PEC applications. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This study focused on the preparation of vertical MoS2 nanosheets with small AuNPs and large AgNPs to achieve synergistic enhancement of SERS and PEC properties. The ternary heterostructure showed the strongest electromagnetic field and surface plasmon coupling, leading to outstanding SERS enhancement and efficient hydrogen evolution reaction (HER) activity.