Fabrication of highly-stable Ag/CA@GTA hydrogel beads and their catalytic application

Abstract

To enhance the stability of a catalyst that uses alginate as a carrier, Ag nanoparticle-loaded glutaraldehyde-crosslinked calcium alginate (Ag/CA@GTA) hydrogel beads were prepared. The Ag/CA@GTA hydrogel beads were characterized by UV-visible spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy analyses. Given that the mechanical strength of the support was remarkably enhanced by crosslinking alginate with GTA, the resulting Ag/CA@GTA beads exhibited high stability and durable activity, with more than 97% conversion within 10 successive cycles, for the catalytic reduction of 4-nitrophenol to 4-aminophenol by NaBH₄ in aqueous solution. These Ag/CA@GTA hydrogel beads were expected to have potential as a highly efficient, cost-effective and eco-friendly heterogeneous catalyst for industrial applications.