Ultrathin MoS2 nanosheets for high-performance photoelectrochemical applications via plasmonic coupling with Au nanocrystals

Abstract

In this work, we prepared ultrathin MoS₂ nanosheets with exposed active edge sites and high electric conductivity that can sufficiently absorb light in the visible region to enable solar energy conversion. The gold nanocrystal–decorated MoS₂ nanosheets facilitate sufficiently enhanced photoelectrochemical water splitting in the UV–visible region. Different Au nanostructures, such as Au nanoparticles and nanorods, were modified on the surface of MoS₂ nanosheets to promote photoelectrochemical water decomposition. By spin-coating a synthetic gold–modified MoS₂ hybrid photoanode on a FTO substrate, the efficiency of photoelectrochemical water oxidation was significantly enhanced, by 2 times (nanorods) and 3.5 times (nanoparticles) in the visible–infrared region; furthermore, the average optical resistance was reduced by a factor of two compared to the MoS₂ photoanode without Au, and the photocurrent increases exponentially when the system bias was greater than 0.7 volts. The Au–MoS₂ metal–semiconductor interface plays an important role in studying the surface plasmon interactions, charge transfer mechanism, and electric field amplification. This rational design for such a unique hybrid nanostructure explains the plasmon-enhanced photoelectrochemical water splitting. This current contribution provides a new path for using the plasmonic metal/semiconductor heterostructure to effectively harvest UV–visible light for solar fuel generation.