Synthesis, Growth Mechanism, and Photocatalytic Properties of Metallic-Bi/Bi13S18Br2 Nano-Bell Heterostructures

Abstract

We report the synthesis of bell-shaped Bi/Bi₁₃S₁₈Br₂ metal/semiconductor heterostructures as a photocatalyst based on nontoxic and Earth-abundant elements. Their unique morphology arises from a multistep growth process, involving (1) the nucleation of Bi₁₃S₁₈Br₂ nanorods, (2) the reduction of a metallic-Bi domain on their surface induced by N,N-didodecylmethylamine, and (3) the heterostructure accretion by a localized reaction at the Bi/Bi₁₃S₁₈Br₂ interface promoted by Ostwald ripening. These heterostructures display remarkable stability in polar solvents, remaining almost unaffected by prolonged exposure to isopropanol and water, and exhibit high photocatalytic efficiency for the degradation of organic dyes (i.e., Rhodamine B and Methylene Blue) under visible-light irradiation, with good recyclability. Additionally, preliminary tests demonstrate CO₂ reduction capabilities, which make these heterostructures promising for both the photocatalytic degradation of pollutants and photoelectrochemical CO₂ conversion. The straightforward synthesis process and the use of nontoxic and Earth-abundant elements offer significant potential for sustainable energy conversion technologies.