Plasmon-Enhanced Photoelectrical Hydrogen Evolution on Monolayer MoS₂ Decorated Cu_1.75 S-Au Nanocrystals

Hydrogen production from water splitting through an efficient photoelectrochemical route requires photoinduced electron transfer from light harvesters to efficient electrocatalysts. Here, the plasmon-enhanced photoelectrical nanocatalysts (NCs) have been successfully developed by coating a monolayer MoS₂ on the Cu_1.75 S-Au hetero-nanoparticle for hydrogen evolution reaction (HER). The plasmonic NCs dramatically improve the HER, leading to 29.5-fold increase of current under 650 nm excitation (1.0 W cm^-2 ). These NCs generate an exceptionally high current density of 200 mA cm^-2 at overpotential of 182.8 mV with a Tafel slope of 39 mV per decade and excellent stability, which is better than or comparable to the Pt-free catalysts with carbon rod as counter electrode. The enhanced HER performance can be attributed to the significantly improved broad light absorption (400-3000 nm), more efficient charge separation and abundant active edge sites of monolayer MoS₂ . The studies may provide a facile strategy for the fabrication of efficient plasmon-enhanced photoelectrical NCs for HER.