Hot Electron of Au Nanorods Activates the Electrocatalysis of Hydrogen Evolution on MoS₂ Nanosheets

Abstract

Efficient water splitting through electrocatalysis holds great promise for producing hydrogen fuel in modern energy devices. Its real application however suffers from sluggish reaction kinetics due to the lack of high-performance catalysts except noble metals such as platinum. Herein, we report an active system of plasmonic-metal Au nanorods/molybdenum disulfide (MoS2) nanosheets hybrids for the hydrogen evolution reaction (HER). The plasmonic Au-MoS2 hybrids dramatically improve the HER, leading to a ∼3-fold increase of current under excitation of Au localized surface plasmon resonance (LSPR). A turnover of 8.76 s(-1) at 300 mV overpotential is measured under LSPR excitation, which by far exceeds the activity of MoS2 catalysts reported recently. The HER enhancement can be largely attributed to the increase of carrier density in MoS2 induced by the injection of hot electrons of Au nanorods. We demonstrate that the synergistic effect of the hole scavengers can further facilitate electron-hole separation, resulting in a decrease of the overpotential of HER at MoS2 to ∼120 mV. This study highlights how metal LSPR activates the HER and promises novel opportunities for enhancing intrinsic activities of semiconducting materials.

Activation Effect of Electrochemical Cycling on Gold Nanoparticles towards the Hydrogen Evolution Reaction in Sulfuric Acid

“…The smallest Tafel slope value of 76.6 AE 1.9 mV/dec was obtained on the Au-NPs/GCE cycled under condition A; this value is 23.4 mV smaller than for uncycled nanoparticles. This decrease of the Tafel slope indicates a faster adsorption of the H* on the cycled nanoparticles, and also suggests that the rate determining factor may not due to a single step [43]. The Tafel slopes for Au-NPs cycled under condition B and C are 91.5 AE 3.9 mV/dec and 110.3 AE 1.5 mV/ dec, respectively.…”

Hot‐Electron‐Mediated Photochemical Reactions: Principles, Recent Advances, and Challenges

“…Hot electron-mediated HER was also reported for AuNRs coupled to MoS 2 nanosheets. [126] Additionally, different semiconductors (e.g., CdS, WO 3 , and Fe 2 O 3 ) have been widely used for hot electron-mediated water splitting by coupling to the plasmonic metallic nanostructures, which effectively increases the photochemical reaction probability. [127][128][129] To utilize hot electrons for chemical reactions, past studies have mainly focused on employing the Schottky barrier to separate hot electrons from the electron-hole pairs.…”

Transition Metal‐Promoted V2CO2 (MXenes): A New and Highly Active Catalyst for Hydrogen Evolution Reaction

“…To assure a sustainable hydrogen generation, tremendous efforts have been made to develop the earth abundant and cost‐effective alternatives to Pt in the past few decades, including non‐precious metal alloys, metal chalcogenides, metal carbides, metal nitrides, metal phosphides, and so on 3, 4, 5, 6, 7, 8. Among these alternatives, 2D layered materials (such as MoS 2 ) have gained broad interest recently because of their extremely large surface areas, low cost, and excellent catalytic activity 9, 10, 11…”