Preparation of cellulose nanocrystal/ silver nanoparticle composite as a catalyst for 4-nitrophenol reduction

Abstract

This paper presented the cellulose nanocrystals (CNC) were synthesized from the Vietnamese agricultural waste, sugarcane bagasse, by a chemical method and then acid hydrolysis. The composite based on CNC and Ag (CNC/Ag) was fabricated by directly synthesizing Ag−NPs on the CNC template with the support of a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB). The morphology, chemical structure and composition of the materials were analyzed by physicochemical methods, ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier−transform infrared spectroscopy (FT−IR), and transmission electron microscopy (TEM). The TEM image results determined that the CNC material was a fibre with an average length and diameter of 400 ± 12 nm and 10 ± 2 nm, respectively. The CNC/Ag composite was used as a catalyst in the 4-nitrophenol (4-NP) reduction to produce 4-aminophenol (4-AP). The 4-NP reduction reaction in the presence of the CNC/Ag catalyst followed a pseudo-first-order reaction kinetics where the catalytic rate constant (kapp) and the catalytic activity factor (k) were 0.25 ± 0.02 min-1 and 20.82 ± 1.4 min^-1. g^-1, respectively. The CNC/Ag catalyst helped this reaction to overcome the kinetic barrier by directly transferring electrons from the BH4− ion to 4-NP through the Ag NPs as an intermediate. In addition, the CNC/Ag material showed the antibacterial activity against both Gram-positive bacteria, Staphylococcus aureus and Gram-negative bacteria, Escherichia coli.