Defect-Induced Epitaxial Growth for Efficient Solar Hydrogen Production

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Epitaxial growth is hindered by lattice mismatches and dangling bonds between dissimilar materials.
• Developing novel heterostructures is crucial for advanced catalytic applications.

Purpose of the Study:

• To demonstrate the epitaxial growth of 2D molybdenum disulfide (MoS₂) ribbons on 1D cadmium sulfide (CdS) nanowires (NWs).
• To investigate the catalytic activity of the resulting MoS₂ ribbon/CdS NWs heterojunction for hydrogen evolution.

Main Methods:

• Utilized surface and subsurface defects in CdS NWs as nucleation sites for MoS₂ growth.
• Characterized the coaxial heterostructure using advanced microscopy and spectroscopy.
• Evaluated the hydrogen evolution performance in an acidic electrolyte.

Main Results:

• Achieved epitaxial growth of [001]-oriented MoS₂ on [0001]-oriented CdS NWs with a near-perfect lattice match (~99.7%).
• Formed coaxial MoS₂ ribbon/CdS NWs heterojunctions with delocalized interface states enhancing charge transport.
• MoS₂ ribbons demonstrated a ~10-fold enhancement in hydrogen evolution compared to platinum, with high apparent quantum yields.

Conclusions:

• Successfully established a novel coaxial epitaxial heterostructure of MoS₂ ribbons on CdS NWs.
• The heterostructure exhibits superior catalytic activity for hydrogen evolution, driven by optimized interface properties.
• This work presents a promising pathway for developing highly efficient cocatalysts for energy conversion applications.