Applications and challenges of elemental sulfur, nanosulfur, polymeric sulfur, sulfur composites, and plasmonic nanostructures

As an abundant and biologically active element, sulfur has been applied in various fields. Through the nanotechnology method, nanosulfur is synthesized with the merits of size effects. Differentiated properties, structures, and functions of sulfur could lead to different applications. In particular, various sulfur composites are synthesized and showed satisfied performance in environmental fields. In addition, plasmonic nanomaterials possess unusual properties and potential applications in mesoscopic physics and the fabrication of nanoscale devices, which may create a new applying direction for sulfur. Undoubtedly, with the wide application, it might pose potential ecological risk and health effects, and the effective strategies for their safe applications are required. Herein, the applications and challenges of sulfur were reviewed in a line of application - risk control - safe application. Till now, although some reviews have discussed sulfur studies in some aspects, but a specific review on sulfur integrating its different sizes and forms is rarely reported. We prepared this review aiming to provide a comprehensive knowledge about sulfur. The current knowledge indicated that there lack sufficient specialized studies on sulfur, and their researching fields, environmental behaviors and fates, characterization, and plasmonic applications.