Epitaxial Grown Sb₂Se₃@Sb₂S₃ Core–Shell Nanorod Radial–Axial Hierarchical Heterostructure with Enhanced Photoelectrochemical Water Splitting Performance

Antimony selenide (Sb2Se3) as a light-harvesting material has gradually attracted the attention of researchers in the field of photoelectrocatalysis. Uniquely, the crystal structure consists of one-dimensional (Sb4Se6)n ribbons, with an efficient carrier transport along the ribbon [001] direction. Herein, a novel Sb2Se3@Sb2S3 core–shell nanorod radial–axial hierarchical heterostructure was successfully fabricated by epitaxial growth strategy. Taking advantage of the isomorphous and anisotropic binding modes of (Sb4S(e)6)n ribbons for Sb2Se3 and Sb2S3, the epitaxially grown core–shell heterostructure forms a van der Waals heterojunction across the radial direction and covalently bonded heterojunction along the axial direction. A photocurrent of 1.37 mA cm–2 was achieved at 0 V vs RHE for the hierarchical Sb2Se3@Sb2S3 nanorod photoelectrode with [101] preferred orientation, up to 40 times higher than for pure Sb2Se3. Moreover, the FeOOH was introduced as a cocatalyst. The photoelectrode decorated with FeOOH shows better stability with a H2 generation rate of 18.9 μmol cm–2 h–1 under neutral conditions. This study provides a new insight into the design of antimony chalcogenide heterostructure photoelectrodes for photoelectrochemical water splitting.