Engineering Interface on a 3D CoNi_1-(OH)₂@MoS₂ Hollow Heterostructure for Robust Electrocatalytic Hydrogen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Heterostructure catalysts are crucial for improving the hydrogen evolution reaction (HER).
• Defining active phase responsibilities and synergy remains a challenge for enhanced HER performance.
• Interface engineering is key to optimizing stepwise-synergetic processes in catalysts.

Purpose of the Study:

• To design and prepare a 3D CoNi(OH)2 hollow structure integrating MoS2 nanosheet catalysts (CoNi(OH)2@MoS2).
• To achieve optimized stepwise-synergetic hydrogen evolution over a universal pH range.
• To elucidate the roles of different active phases and their interfaces in enhancing HER.

Main Methods:

• Synthesis of a 3D hollow heterostructure integrating CoNi(OH)2 and MoS2 nanosheets.
• Interface assembly engineering to create dual active phases.
• Electrochemical characterization for HER activity and stability testing.
• Density functional theory (DFT) calculations to understand reaction mechanisms.

Main Results:

• The 3D CoNi(OH)2@MoS2 hollow structure demonstrated superior HER activity and stability across a universal pH range.
• The unique structure effectively prevented MoS2 agglomeration and enhanced CoNi(OH)2-MoS2 heterointerfaces.
• DFT calculations confirmed distinct active sites for water dissociation and H* adsorption/H2 generation at the heterointerfaces, optimizing the energy barrier.

Conclusions:

• The designed CoNi(OH)2@MoS2 heterostructure provides an effective strategy for highly efficient electrocatalysts.
• Interface engineering with defined responsible active phases is a promising approach for HER.
• The study highlights the importance of synergistic effects between different active phases in heterostructure catalysts.