Highly Sustainable h-BN Encapsulated MoS₂ Hydrogen Evolution Catalysts

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Two-dimensional (2D) catalysts like molybdenum disulfide (MoS2) are crucial for hydrogen evolution reactions (HER).
• MoS2 catalysts are vulnerable to degradation in harsh electrolytes due to oxidation from moisture and oxygen, limiting their practical application.
• Enhancing the stability of MoS2 catalysts is critical for sustainable hydrogen production.

Purpose of the Study:

• To improve the long-term stability of MoS2 catalysts for the hydrogen evolution reaction (HER).
• To investigate the protective effect of an atomically thin hexagonal boron nitride (h-BN) layer on MoS2 catalysts.
• To achieve ultra-high current densities and super stable catalytic performance in MoS2-based HER systems.

Main Methods:

• Passivation of monolayered MoS2 catalysts with an atomically thin hexagonal boron nitride (h-BN) layer.
• Experimental evaluation of catalytic performance, including current density and stability over extended periods.
• Density functional theory (DFT) calculations to understand the mechanism of passivation and proton interaction.

Main Results:

• The h-BN passivated MoS2 catalysts demonstrated ultra-high current density (500 mA cm⁻² over 11 h).
• Exceptional stability was achieved, with sustained performance at 150 mA cm⁻² for 64 hours.
• DFT calculations confirmed that the h-BN layer prevents direct water/acid adsorption while allowing proton penetration, preserving the MoS2 structure.

Conclusions:

• Atomically thin h-BN passivation effectively protects MoS2 catalysts from degradation in harsh electrolytes.
• The protected MoS2 catalysts exhibit significantly enhanced catalytic activity and long-term stability for HER.
• This approach offers a promising strategy for developing practical, highly stable 2D MoS2 catalysts for high-current hydrogen evolution.