Carboxymethyl cellulose macromolecules as generator of anisotropic nanogold for catalytic performance

Morphological structure and size of Au nanoparticles (AuNPs) are basically affected on their chemical reactivity which are influenced by preparation method due to including different materials and may cause some interferences in their reactivity. Hence, current work focused on preparation of anisotropic AuNPs with astonishing catalytic reactivity, using carboxymethyl cellulose (CMC) macromolecules, as generator and shape conductor. Geometrical shape and size distribution of the so-obtained AuNPs were found to be dependent on CMC concentration and addition of alkali. By using 2 g/L CMC, sharp and quite intense SPR peak was observed for the spherical AuNPs with size of 8.8-14.0 nm. While, agglomerated Au particles with larger size (432.4-488.3 nm) showed broader Surface Plasmon Resonance peak in case of alkali addition. Using lower concentration of CMC (1 g/L) resulted in formation of heterogeneous shapes (nano-prism and nano-hexagonal). The small sized Au nano-spheres were shown to exhibit the highest catalytic action. The p-nitro-aniline was fully reduced to p-amino-aniline in only 1 min and achieved rate constant of 649.2 × 10^-3 s^-1. This work offers a unique, simple and green methodology to prepare catalytically active anisotropic AuNPs which could be highly applicable in different purposes.