Topotactic Transformation of Single-Crystalline Precursor Discs into Disc-Like Bi2S3 Nanorod Networks

Hierarchical, two‐dimensional (2D), disc‐like networks consisting of crossed single‐crystalline Bi2S3 nanorods have been synthesized via a novel 2D‐template‐engaged topotactic transformation process, which involves the formation of intermediate BiOCl single‐crystalline discs and their subsequent chemical transformation into disc‐like Bi2S3 nanofabrics. The transformation process from (001)‐oriented BiOCl discs to disc‐like Bi2S3 nanorod networks has been followed by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and X‐ray diffraction (XRD), which revealed that the close matching between the lattice constants of the c‐axis for orthorhombic Bi2S3 and the a‐ or b‐axis for tetragonal BiOCl could be responsible for the preferential growth of [001]‐oriented Bi2S3 nanorods on the top faces of (001)‐oriented BiOCl discs along the two perpendicular [100] and [010] directions of BiOCl. The diameter of the Bi2S3 nanorods involved in the networks can be adjusted by changing the bismuth ion concentration in the reaction solution; moreover, an increase of the HCl concentration would prevent the formation of precursor BiOCl discs, leading to the formation of Bi2S3 nanostructures with varied morphologies. Charge–discharge curves and cyclic voltammograms of the obtained Bi2S3 nanostructures were measured to investigate their electrochemical hydrogen storage behaviors. It was found that the disc‐like Bi2S3 nanorod networks could electrochemically charge and discharge with a capacity of 162 mA h g−1 at room temperature, indicating their potential applications in hydrogen storage, high‐energy batteries, and catalytic fields. Hierarchical disc‐like networks consisting of a layer of crossed single‐crystalline Bi2S3 nanorods are synthesized via a novel 2D‐template‐engaged topotactic transformation process, which involves the formation of intermediate BiOCl single‐crystalline discs and their subsequent chemical transformation into disc‐like Bi2S3 nanofabrics (see figure).