Defects engineering of Au@MoS2 nanostructures for conventional and plasmon-enhanced hydrogen evolution reaction

Abstract

The influence of thermal treatment under reducing conditions on the structural and hydrogen evolution reaction (HER) properties of Au@MoS2 structures is reported in this work. After a thermal treatment at 800 °C under H2 atmosphere, the Au@MoS2 nanostructures exhibit remarkable performance with an overpotential of 203 mV vs reversible hydrogen electrode (RHE) at 10 mA/cm2 and a Tafel slope of 55 mV/dec which is similar to the value reported for edges sites in MoS2. The samples were investigated by combining ex-situ and in-situ aberration-corrected transmission electron microscopy (TEM) experiments under controlled atmosphere, Raman and XPS spectroscopies. (S) TEM characterization highlights the formation of the core-shell system as well as the decrease of the number of shell layers up to incomplete layers induced by the thermal treatments. The plasmonic-assisted HER performances of these nanostructures under LED illumination are also explored and an enhancement by about 10 % of the current density, depending on the wavelength used, is also reported. These results open new avenues for the design of core shell nanostructures based on transition metal dichalcogenides for the hydrogen evolution reaction.