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.