Corncob-derived nanocellulose-supported palladium nanoparticles towards catalytic reduction of 4-nitrophenol

Abstract

This study proposed the efficient extraction of nanocellulose from an agricultural residue and the facile immobilization of metal nanoparticles on the surface of nanocellulose without using any external surfactants. In which, corncob was successively treated by an alkaline aqueous solution, a bleaching agent, and a strong acid in order to achieve nanocellulose, which was subsequently served as a support for palladium nanoparticles (PdNPs/NC). Nanocellulose and PdNPs/NC were thoroughly examined involving Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Such successive chemical treatments of corncob yielded nanocellulose with crystallinity index of over 90 %, and palladium nanoparticles (4.9 % wt. Pd) were successfully immobilized on cellulose nanofibrils (∼50 nm in diameter, micrometers in length). Such a catalytic system (PdNPs/NC) was utilized in the selective reduction of 4-nitrophenol to form 4-aminophenol at room-temperature, complying the pseudo-first-order kinetics (k = 0.1144 min−1), relative to a turnover frequency (TOF) of 1.91 h−1, validating the high reactivity of the newly-generated nanocatalyst.