1 Chalcogenides and their nanocomposites: fundamental, properties and applications 2 Chalcogenides and their nanocomposites in environmental remediation 3 Chalcogenides and their nanocomposites in photocatalytic reactions 4 Metal chalcogenides and their nanocomposites in water purification systems 5 Metal chalcogenides and their nanocomposites in industrial effluents treatments 6 Heterostructured transition metal chalcogenides photocatalysts for organic contaminants degradation 7 Chalcogenides and their nanocomposites in heavy metal decontamination 8 Chalcogenides and their nanocomposites in oxygen reduction 9 Chalcogenides and their nanocomposites as supper capacitive materials 10 Metal-chalcogenides nanocomposites as counterelectrodes for olar cells 11 II-VI semiconductor metal chalcogenide nanomaterials and polymer composites: fundamentals, properties, and applications 12 Challenges and opportunities of chalcogenides and their nanocomposites