Nature provides a rich panoply of structural motifs comprised of composites whose mechanical properties exceed those of their individual components. The human endeavor to likewise craft value‐added structural materials from underappreciated, sustainably sourced feedstocks remains a formidable challenge. Herein, efforts are made to achieve durable composites by synergistic combination of sulfur and cellulose. Composites are achieved in which bulk sulfur is reinforced by a network of 1–20% by mass cellulose cross‐linked with polysulfide chains. Composites described herein are remeltable and have flexural strength exceeding that of Portland cement. A thorough analysis of these materials has been undertaken through nuclear magnetic resonance, infrared spectroscopy, Raman spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. These analyses of both as‐prepared composites and fractionated materials unequivocally validate the formulation of these composites and the separability of the bulk sulfur from the reinforcing polysulfide‐cross‐linked cellulose network. The thermomechanical properties of these recyclable composites portend their tantalizing potential to supplant inherently unsustainable structural elements in numerous commercial applications. Further applications to improve the environmental resistance and flexural strength of Portland cement by treatment with the sulfur–cellulose composites are also discussed.

Plasmonic single-crystal silver nanoparticles exhibit high efficiency for the interaction with light and low intrinsic losses across the visible and near-infrared spectral ranges as manifested by weak light absorption and strong light scattering. The addition of a thin surface silver sulfide layer radically increases the light absorption at the expense of decreasing the light scattering. The hybrid silver/silver sulfide nanoparticles retain the high interaction efficiency despite partial damping of the plasmon resonance by the silver sulfide layer. It is postulated that the light energy absorbed by the hybrid nanoparticles is “deposited” in the thin silver sulfide layer, thus opening possibilities for its further utilization. The hybrid nanoparticles of different sizes with varying silver sulfide thickness were characterized by absorption and scattering spectroscopy as well as by X-ray diffraction and atomic force microscopy. The described hybrid nanoparticles present a general strategy for the rational design of structures exhibiting strong light absorption across the visible and near-infrared spectral ranges via the excitation of plasmon resonances.

The addition of metals to the oligomeric sodium metasilicate in water results in insoluble metal silicate complexes that form nanoparticles, in which further chemical reactions can be carried out. Copper sulfide, copper tin sulfide, tin sulfide, bismuth sulfide and zinc sulfide doped with manganese nanoparticles were synthesized using this method. The silicate matrix resulted in a narrow particle size distribution and imparted long-term stability to the nanoparticle suspensions. The reac-tions were monitored via UV-Vis-NIR spectroscopy, and the nanoparticles were characterized by AFM, powder X-ray diffraction, and Raman spectroscopy. The described method is expected to become a general and versatile approach for aqueous synthesis of multimetallic, doped chalcogenide and other complex nanoparticles without the need of complicated chemical precursors, stabilizing agents, and multiple steps.