Achieving highly efficient electrocatalytic hydrogen evolution with Co-doped MoS₂ nanosheets

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Molybdenum disulfide (MoS₂) shows promise as a hydrogen evolution reaction (HER) catalyst, but its activity is limited by the inert basal plane.
• The side edges of MoS₂ exhibit platinum-like activity, necessitating strategies to enhance basal plane utilization.

Purpose of the Study:

• To develop highly active and stable molybdenum disulfide (MoS₂) catalysts for the hydrogen evolution reaction (HER) through element doping.
• To investigate the effect of cobalt (Co) doping on the phase transformation and catalytic performance of MoS₂ nanosheets.

Main Methods:

• Hydrothermal synthesis of cobalt-doped 1T-MoS₂ nanosheets grown on carbon cloth (CC).
• Phase transformation analysis using structural tests to confirm the 1T phase content.
• Electrochemical measurements to evaluate HER activity, including overpotential and Tafel slope.

Main Results:

• Co-doped 1T-MoS₂/CC exhibited superior HER activity with an overpotential of 69 mV at 10 mA cm^-2 and a Tafel slope of 81.84 mV dec^-1.
• Co doping induced a phase transformation from 2H to 1T MoS₂ (67%), further enhanced by TMA⁺ addition to 79%.
• The catalyst demonstrated excellent durability, maintaining performance for over 100 hours at 100 mA cm^-2 in an alkaline medium.

Conclusions:

• Cobalt doping is an effective strategy to enhance the HER activity and stability of MoS₂ catalysts by promoting the formation of the active 1T phase.
• The strong interface binding between MoS₂ and CC contributes to the catalyst's excellent durability.
• This work provides a new approach for designing efficient and robust MoS₂-based electrocatalysts via element doping.