Surface states in bulk single crystal of topological semimetal Co$_3$Sn$_2$S$_2$ towards water oxidation

TL;DR

This study investigates the topological surface states of bulk Co$_3$Sn$_2$S$_2$ crystals and their role in enhancing water oxidation catalysis, highlighting the potential of topological materials in electrocatalyst design.

Contribution

It demonstrates that bulk Co$_3$Sn$_2$S$_2$ hosts robust topological surface states that serve as efficient catalytic centers for oxygen evolution, linking topological properties to catalytic performance.

Findings

Co$_3$Sn$_2$S$_2$$ naturally hosts topological surface states.

The material exhibits high OER catalytic activity despite small surface area.

Topological surface states enhance electron transfer in catalytic processes.

Abstract

The band inversion in topological phase matters bring exotic physical properties such as the emergence of a topologically protected surface states. They strongly influence the surface electronic structures of the investigated materials and could serve as a good platform to gain insight into the catalytic mechanism of surface reactions. Here we synthesized high-quality bulk single crystals of the topological semimetal Co$_3$Sn$_2$S$_2$. We found that at room temperature, Co$_3$Sn$_2$S$_2$ naturally hosts the band structure of a topological semimetal. This guarantees the existence of robust surface states from the Co atoms. Bulk single crystal of Co$_3$Sn$_2$S$_2$ exposes their Kagome lattice that constructed by Co atoms and have high electrical conductivity. They serves as catalytic centers for oxygen evolution process (OER), making bonding and electron transfer more efficient due to the partially filled $e_g$ orbital. The bulk single crystal exhibits outstanding OER catalytic performance, although the surface area is much smaller than that of Co-based nanostructured catalysts. Our findings emphasize the importance of tailoring topological non-trivial surface states for the rational design of high-activity electrocatalysts.