Silver nanoparticle synthesis mediated by carboxylated cellulose nanocrystals

Synthesis of silver (Ag) nanoparticles (NPs) using sustainable chemical methods has drawn significant interest. Here a new route for AgNP formation by using TEMPO-oxidised cellulose nanocrystals (TEMPO-CNCs) is proposed. Sodium borohydride was used to reduce precursor Ag ions and the effect of carboxyl surface density of TEMPO-CNCs on the rate of nucleation and resultant size distribution of AgNPs was investigated. The rate of NP nucleation was inversely related to the carboxyl content of CNCs. On the contrary, the ability of TEMPO-CNCs to prevent the aggregation of AgNPs was directly related to the carboxyl content of CNCs. In comparison with earlier reported study dealing with the role of sulfate groups in CNCs, here the role of surface carboxyls is investigated over much wider range of concentration, thus allowing a more comprehensive study of the effect of surface charge on the size distribution of AgNPs formed. These results add to the current understanding of the mechanistic aspects related to synthesis and stabilisation of AgNP in a sustainable way.