Using Exciton/Trion Dynamics to Spatially Monitor the Catalytic Activities of MoS₂ during the Hydrogen Evolution Reaction

Abstract

The adsorption and desorption of electrolyte ions strongly modulates the carrier density or carrier type on the surface of monolayer-MoS2 catalyst during the hydrogen evolution reaction (HER). The buildup of electrolyte ions onto the surface of monolayer MoS2 during the HER may also result in the formation of excitons and trions, similar to those observed in gate-controlled field-effect transistor devices. Using the distinct carrier relaxation dynamics of excitons and trions of monolayer MoS2 as sensitive descriptors, an in situ microcell-based scanning time-resolved liquid cell microscope is set up to simultaneously measure the bias-dependent exciton/trion dynamics and spatially map the catalytic activity of monolayer MoS2 during the HER. This operando probing technique used to monitor the interplay between exciton/trion dynamics and electrocatalytic activity for two-dimensional transition metal dichalcogenides provides an excellent platform to investigate the local carrier behaviors at the atomic layer/liquid electrolyte interfaces during electrocatalytic reaction.

Selective activation of MoS2 grain boundaries for enhanced electrochemical activity

“…Previous work has demonstrated the attractiveness of such structures for enhancing a 2D material's photocatalytic properties as it enhances exciton separation and carrier lifetime. 50,51…”

Spatially Confined Microcells: A Path toward TMD Catalyst Design

“…The principle of TR-LCM is to record the exciton and trion dynamics which is highly sensitive to the local charge environment induced by the adsorption and desorption of electrolyte ions, thus reflecting the local catalytic activity. Luo and colleagues developed TR-LCM to realize the visualization of the catalytic activity of monolayer MoS 2 during HER (Figure a) . During the experiment, the transient transmittance charge (Δ T / T , carrier dynamics) was recorded at different electrochemical potentials in 0.1 M HClO 4 electrolyte (Figure b).…”

“…(e) Evolution of ultrafast Trion (in red) distribution over time at potentials of −0.3 V RHE . Adopted with permission from ref . Copyright 2022 American Chemical Society.…”

K Intercalation-Assisted Co-Doped MoS2 Nanoflowers for an Efficient Hydrogen Evolution Reaction

“…It has the potential for use in a broad range of applications. − Among various H 2 generation technologies, electrochemical water hydrolysis enabled by renewable energy shows great promise for ecofriendly hydrogen production. Pt-based catalysts are currently the state-of-art electrocatalysts for electrocatalytic hydrogen evolution. , However, due to their rarity and exorbitant cost, large-scale implementation of water splitting remains extremely challenging. , As a promising alternative, 2D transition metal disulfides have garnered considerable attention as cost-effective and Earth-abundant electrocatalysts for hydrogen production. , …”