Theoretical insight into surface structures of pentlandite toward hydrogen evolution

Area of Science:

• Materials Science
• Catalysis
• Computational Chemistry

Background:

• Pentlandite (Fe,Ni)9S8 is a transition-metal catalyst with potential for the hydrogen evolution reaction.
• Experimental observations show a long activation process and facet-dependent activity, which require theoretical explanation.

Purpose of the Study:

• To theoretically investigate the facet-dependent hydrogen evolution activity of pentlandite.
• To elucidate the role of surface structures and electronic properties in pentlandite's catalytic performance.

Main Methods:

• Density functional theory (DFT) calculations were employed.
• The study focused on the (111) and (311) synthetic surfaces of pentlandite.

Main Results:

• Small metal cubes are crucial for surface stability and remain intact during catalysis.
• Linking sites bridging metal cubes are identified as the primary active sites for hydrogen evolution.
• Metal cubes tune the electronic structures of linking sites, optimizing their free energy for catalysis.

Conclusions:

• The catalytic activity of pentlandite is strongly influenced by its surface structure, particularly the metal cubes and linking sites.
• Surface reconstruction, such as the conversion between (311) and (111) facets, can occur and impact activity.
• Engineering surface structures offers a viable strategy to enhance the hydrogen evolution performance of (Fe,Ni)9S8.