In situ synthesis of silver nanoparticles with controllable size distribution and high content in bagasse nanocellulose hydrogel

Developing an environment-friendly preparation method for silver nanoparticles (AgNPs) composite is significant. However, it remains challenges in size adjustment and content improvement of AgNPs. Here, the NaIO4 oxidation and TEMPO-mediated oxidation were applied to bagasse pulp to prepare nanocellulose (NC) with both carboxyl and aldehyde groups. The aldehyde content of NC could be adjusted in the range of 0.21–1.45 mmol/g by different NaIO4 oxidation times. When the carboxyl groups were protonated, NC with a high length-diameter ratio could construct stable hydrogels in a low concentration at 0.5 wt%. The NC hydrogels showed excellent in situ synthesis ability of AgNPs with abundant pore structure. By regulating the carboxyl group content of NC, the size distribution of synthesized AgNPs could be controlled in the range of 7.14–28.6 nm with high content of 6.79–11.0 %. The NC/AgNPs composite hydrogel exhibited high catalytic degradation activity for 4-nitrophenol and antibacterial activity. This approach for constructing NC hydrogel paves the way for AgNPs composite products with adjustable sizes and high contents.