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Proton-Controlled Electron Injection in MoS2 During Hydrogen Evolution Revealed by Time-Resolved
Tao Yang1,2, Boning Wu2, Chunmei Ding3
1Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Journal of the American Chemical Society
|January 22, 2025
Summary
Electron injection into molybdenum disulfide (MoS2) for hydrogen evolution reaction (HER) catalysis is influenced by proton concentration. Optimizing this interface enhances HER electrocatalyst performance.
Area of Science:
- Materials Science
- Electrochemistry
- Surface Science
Background:
- Monolayer molybdenum disulfide (MoS2) shows promise as an electrocatalyst for the hydrogen evolution reaction (HER).
- Catalytic performance is limited by factors beyond active sites, including substrate electron injection.
- The nonclassical, liquid-gated electron injection mechanism at the substrate-MoS2 interface requires further investigation.
Purpose of the Study:
- To investigate the dynamics of electron injection into monolayer MoS2 under HER conditions.
- To characterize the current density-potential (J-E) behavior at the substrate-MoS2 interface.
- To elucidate the role of proton concentration in substrate-MoS2 electron transfer.
Main Methods:
- Nanosecond time-resolved spectroelectrochemistry to probe electron injection dynamics.
- Transient current measurements to determine electron density at the substrate.
- Combined spectroelectrochemical and transient current analysis to study interface charge transfer.
Main Results:
- Electron injection barrier and capability are strongly correlated with electrolyte proton concentration.
- Proton concentration influences the electron density within the MoS2 layer.
- Observed relationship suggests electron concentration-dependent conductivity of MoS2.
Conclusions:
- Proton concentration is a critical factor governing electron injection efficiency in MoS2 HER electrocatalysts.
- Understanding and controlling the substrate-MoS2 interface is key to optimizing catalytic performance.
- Higher proton concentrations may reduce stray electrons, facilitating efficient injection and improving HER.
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