Hybridizing Strong Quadrupole Gap Plasmons Using Optimized Nanoantennas with Bilayer MoS2 for Excellent Photo-Electrochemical Hydrogen Evolution

Plasmonic nanoantennas with efficient scattering and strong electromagnetic field confinement are integrated into atomically thin transition metal dichalcogenides to gain insight into nanoscale light-matter interactions. Herein, unusual quadrupole gap plasmons (QGPs) are introduced in the tailored nanoantennas. The field enhancement of such QGPs is further maximized by optimizing the structure of the nanoantennas using a statistical method. In addition, the optimized nanoantennas are employed on a chemical vapor reaction-grown bilayer molybdenum disulfide (MoS2) to tune and intensify the optical response of MoS2. The optimized QGP structure performance was enhanced by a factor of 27.87 and a beneficial continuous bilayer MoS2 can be applied in the hydrogen evolution reaction (HER) with superior outcomes. MoS2@QGP acts as an excellent photocatalyst for HER activity because of its accelerated electron injection process, which is faster than the electron-hole pair recombination, supported by the good light-trapping capacity of the QGP structure and plentiful accepting sites of the continuous bilayer MoS2 film. The experimental results demonstrate that the QGP enhances the intrinsic catalytic properties of bilayer MoS2 for photocatalytic reactions.