Alanine based coordinating ligand mediated hydrothermal synthesis of CuS nano/microstructures and morphology dependent photocatalysis

CuS nano/microstructures with different morphologies, such as solid microspheres with blocks (1-CuS), nanospheres (2-CuS) and microspheres of nanoflakes (3-CuS), were synthesized using alanine based coordinating ligands (1-3) as structure controlling agents in hydrothermal synthesis. Interestingly, copper coordination polymers (4 and 5) that were prepared using the same ligand (2) but differed subtly in the coordination and water molecule presence produced distinctly different nano/microstructures. Hydrogen-bonded network polymer 4 gave CuS microspheres composed of nanocrystals (4-CuS) whereas coordination network polymer without water molecules 5 yielded nanocrystalline powdered materials (5-CuS). Importantly, the synthesised CuS nano/microcrystals exhibited dye degradation (methylene blue (MB), methyl orange (MO) and Rhodamine blue (RB)) at room temperature without using any specific light source. The CuS nano/microcrystals also showed morphology dependent dye degradation properties. The most efficient dye degradation was observed for nanosphere 2-CuS whereas 1-CuS and 4-CuS exhibited comparatively slow dye degradation. Thus, the present work demonstrates the utility of simple coordinating ligands and subtle changes in the coordination network for tuning CuS morphologies which showed morphology dependent dye degradation.