Small molecular amine mediated synthesis of hydrophilic CdS nanorods and their photoelectrochemical water splitting performance

Abstract

Photoelectrochemical (PEC) water splitting is a promising route for solar energy harvesting and storage, but it has been highly limited by the performance of the semiconductor photoelectrodes. Herein, we report a small molecular amine-mediated solvothermal method for synthesizing CdS nanorods. The obtained CdS nanorods are hydrophilic and can be easily dispersed in water. Furthermore, the small molecular amine, activating elemental sulfur and mediating the growth of CdS, all play a role similar to that of long-chain surfactant molecules in "non-aqueous" systems. Thus, the obtained CdS nanorods show uniform shape with monodispersed size, the length of which can be tuned by the sulfur dosage. In addition, the CdS nanorods show a broader light absorption than CdS nanoparticles. Their photoelectrochemical water splitting performances were then tested. Under light irradiation of λ > 200 nm, the photocurrent density of CdS nanorods at -0.2 V bias potential (vs. Ag/AgCl) is found to be 25 times of that obtained with CdS nanoparticles. The present finding demonstrates that small amine molecules could be efficient mediators for the synthesis of hydrophilic sulfides with high quality. The simple synthesis method and the good photoelectrochemical properties illustrate the hydrophilic CdS nanorods are potential candidate for photoelectrochemical applications.

Crystal growth and shell layer crystal feature-dependent sensing and photoactivity performance of zinc oxide–indium oxide core–shell nanorod heterostructures

“…A larger crystallite size and a more rugged crystal morphology cause a larger redshift of the absorption shoulder of semiconductor materials. 34,35 Moreover, a crystal defect-induced optical band edge redshift has been shown in several oxide semiconductors. 36,37 The InO shell of ZnO-InOIJL) was composed of large prism-shaped InO crystallites; moreover, the presence of many rugged regions on and numerous defects in the InO shell layer accounted for the observed optical absorption results herein.…”

A stable inverse opal structure of cadmium chalcogenide for efficient water splitting

“…The two factors jointly elevate IPCE of the IOS electrode to a value ~2.9 times (1.2×2.4) that of CdS film, which is almost consistent with the experimental value (~3). [37][38][39][40][41][42][43] However, the PEC stability of this heterogeneous IOS ( Figure S15) should be further improved. This conclusion is supported by the similar carrier concentrations in IOS (2.3×10 16 cm -3 ) and thin film (5×10 16 electron transfer, leading to a charge transfer efficiency of approximately 100% in both electrodes.…”

CdS Photocatalysts Modified with Ag: Effect of the Solvothermal Temperature on the Structure and Photoactivity for Hydrogen Production

“…Solvothermal methods have attracted much interest for the nanosynthesis of CdS because they can control the crystal growth of CdS through the coordination of the solvent with the Cd 2+ ions in combination with the adjustment of the synthesis variables such as temperature, time and precursors employed. Among the different solvents used in the solvothermal nanosynthesis of CdS, ethylenediamine (EDA) has demonstrated to be an interesting solvent due to its ability to form planar complexes with the Cd 2+ ions [Cd(EDA) 2 ] 2+ which produces well-oriented two-dimensional nanostructures after the combination with the S 2− ions [16,17]. The evolution of these initial two-dimensional nanostructures towards well-crystallized monodimensional structures is highly dependent on the temperature of synthesis, as it was described by Mahdi et al [18].…”