Oxidizing Properties of the Polysulfide Surfaces of Patronite VS4 and NbS3 Induced by (S2)2− Groups: Unusual Formation of Ag2S Nanoparticles

Abstract Similarly to transition metal dichalcogenides akin to MoS 2 , transition metal polysulfides like tri‐ and tetrachalcogenide materials are nowadays incorporated into catalysts and composites used for energy conversion and storage, etc. However, polysulfide structures feature  S  S  units, which make them strikingly different from the widely known MoS 2 and other dichalcogenides. At the same time, their surface chemistry and its relation to properties are very little studied. Reported here is one of the first observations on the oxidizing properties of disulfide bridges (  S  S  ) 2− forming surfaces in polysulfide crystals. Upon interaction with silver salts or silver nanoparticles, MoS 2 acts as most supports, that is, it stabilizes metallic Ag at its surface; in contrast, curiously, patronite VS 4 and NbS 3 stabilize Ag 2 S nanoparticles under identical reducing conditions. The Ag/MoS 2 , Ag 2 S/NbS 3 , and Ag 2 S/VS 4 samples are characterized with X‐ray diffraction, transmission electron microscopy, and X‐ray photoelectron spectroscopy. Apparently, the unexpected formation of Ag 2 S is due to complex redox processes involving disulfide fragments –S–S– of nanorods VS 4 or nanoribbons NbS 3 , which are absent in MoS 2 nanosheets. This result is important for fundamental understanding of the properties of sulfur‐rich surfaces and also for contributing to the number of available synthetic paths toward Ag 2 S nanoparticles.