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Regulating Local Atomic Environment around Vacancies for Efficient Hydrogen Evolution.

Wenqi Zhan1, Xingwu Zhai1, Yuhuan Li2

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|March 27, 2024
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Summary

Manipulating local atomic environments in molybdenum disulfide (MoS2) vacancies enhances hydrogen evolution reaction (HER) electrocatalysis. Mo-rich vacancies boost HER performance by optimizing hydrogen adsorption and per-site activity.

Keywords:
atomic environmentexposed molybdenumhydrogen evolution reactionmolybdenum disulfidevacancies

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Area of Science:

  • Materials Science
  • Catalysis
  • Nanotechnology

Background:

  • Defect engineering is crucial for designing advanced electrocatalysts.
  • Focus has been on vacancies, but the local atomic environment's role is understudied.
  • Understanding vacancy structure-activity relationships is key for catalyst optimization.

Purpose of the Study:

  • To investigate the impact of local atomic environments of vacancies in molybdenum disulfide (MoS2) on catalytic activity.
  • To develop a facile method for manipulating vacancy structures in MoS2.
  • To correlate specific vacancy structures with hydrogen evolution reaction (HER) performance.

Main Methods:

  • Developed a synthetic approach to control Mo-to-S ratios and thus local atomic environments of vacancies in MoS2.
  • Synthesized MoS2 samples with varying vacancy types (Mo-terminated, S-terminated, and defect-free).
  • Evaluated the electrocatalytic performance of synthesized MoS2 for the hydrogen evolution reaction (HER).

Main Results:

  • MoS2 with Mo-terminated vacancies demonstrated superior HER performance compared to S-terminated and defect-free MoS2.
  • The enhanced performance is attributed to tunable orbital orientation and distribution around vacancies.
  • Optimized local atomic environments facilitate favorable hydrogen adsorption, increasing intrinsic per-site activity.

Conclusions:

  • The local atomic environment of vacancies significantly influences electrocatalytic activity in MoS2.
  • Mo-terminated vacancies are more effective for HER catalysis than S-terminated ones.
  • This work provides insights for rational defect engineering in transition metal dichalcogenides (TMDs) and other catalysts.