Chemically Filled and Au-Coupled BiSbS₃ Nanorod Heterostructures for Photoelectrocatalysis

The synergistic effects of foreign ion incorporation into a semiconductor host crystal lattice can produce new functional properties. This concept has been adopted in the design of various energy materials for light harvesting, charge transport, and energy storage applications. Going beyond the traditionally used group II–VI and III–V semiconductor nanostructures, herein, 1D materials involving Bi­(III) and Sb­(III) sulfides are reported. Upon Sb dilution into the Bi₂S₃ lattice, exciting new material properties, including induction of localized surface plasmon resonance (LSPR) and a drastic change to the 1D crystal growth pattern, were observed. The presence of the Sb­(III) precursor along with Bi­(III) led to nanotubes with controlled length as the ultimate product, and their transformation to nanorods via chemical filling emerged as a new fundamental mechanism of crystal growth. Due to its slow thermal decomposition rate, the Sb­(III) precursor dominantly filled these tubes, resulting in graded alloy Bi_1.09Sb_0.91S₃ (BAS) nanorods. Further, by coupling with Au via seeded nucleation, Au–Bi_1.09Sb_0.91S₃ (Au-BAS) 1D heteronanostructures were designed, in which Au remained at the center of the BAS nanorods. On the basis of these advantages, these nanostructures were employed for photoelectrocatalytic (PEC) water splitting, and significant enhancement was observed in the Au-coupled rods.