Quick catalytic responsive chitosan flakes@Ag/CuO nanocomposites in organic synthesis and environmental remediation

This report deals with polymeric microgel of chitosan flakes (CF) for catalytic applications of bimetallic Ag/CuO nanoparticles (NPs). Nanocomposites, based on fabricated chitosan flakes, act as nanocatalyst and are used for swift chemical reduction of methylene blue (MB), para-nitro phenol (PNP) and dimethyl amino-benzaldehyde (DMAB) in presence of sodium borohydride or UV light. In our present work N-hydroxyl methyl acrylamide, instead of the traditional divinylic cross linker, has been employed as monomer as well as cross linker for the synthesis of chitosan flakes. The fabricated chitosan flakes have been doped with Ag/CuO NPs to yield nano-composites. Three grades of nanocomposites have been synthesized by varying the amounts of N-hydroxyl methyl acrylamide, to optimize the crosslinking and suitable network, to yield stabilized NPs. FT-IR, XRD, TGA, SEM, TEM, EDX, DLS and Ultraviolet-Visible (UV-Vis.) spectroscopic characterization techniques have been performed to establish the polymeric chitosan flakes and nanocomposites. When the nanocomposites are employed as catalysts, the percentages of reduction of MB, PNP and DMAB, using sodium borohydride (NaBH4) or presence of UV-light, are over 90%, with lesser reaction time. The catalytic reduction in case of NaBH4 exhibits pseudo first order kinetics and the corresponding rate constant (kapp) values have been determined.