Electrosynthesis of CdS/MoS2 Using Electrodeposited MoSx: A Combined Voltammetry-Electrochemical Quartz Crystal Nanogravimetry Study

Here, we describe a strategy for preparing CdS/MoS2 heterostructures using initially electrodeposited MoSx on a polycrystalline gold substrate. The excess sulfur intrinsic to the electrodeposited MoS3 surface was derivatized with Cd to form spherical CdS/MoS2 particles by judicious adjustment of the medium pH and interfacial electrochemistry. The progression of this conversion was monitored by a combination of cyclic/linear sweep voltammetry coupled with electrochemical quartz crystal nanogravimetry. The electrodeposited MoSx and CdS/MoS2 films were further characterized by scanning electron microscopy, energy-dispersive X-ray analysis, laser Raman spectroscopy, and X-ray photoelectron spectroscopy. Heterojunction formation between MoS2 and CdS particles was confirmed by high-resolution transmission electron microscopy as well as via Kelvin probe measurements of the contact potential differences, with and without the presence of CdS on the MoS2 surface. The nonoptimized CdS/MoS2 heterostructures showed improved photoelectrochemical response compared with CdS or MoS2 for oxidation of sulfite species.

Automated summary

A strategy for preparing CdS/MoS2 heterostructures was described in this study, where CdS/MoS2 particles were formed by derivatizing the excess sulfur intrinsic in the electrodeposited MoS3 surface with Cd through adjustment of medium pH and interfacial electrochemistry. The formation of heterojunction between MoS2 and CdS particles was confirmed, and the nonoptimized CdS/MoS2 heterostructures showed improved photoelectrochemical response for oxidation of sulfite species compared with CdS or MoS2.