One-Pot Synthesis of Magnetic Nanocellulose/Fe3O4 Hybrids Using FeCl3 as Cellulose Hydrolytic Medium and Fe3O4 Precursor

A facile one-pot method was reported for synthesizing magnetic cellulose nanocrystals (CNC) loaded with iron tetroxide (Fe 3 O 4 ) nanoparticles. Initially, microcrystalline cellulose (MCC) was treated with a 1 M solution of ferric chloride (FeCl 3 ) and hydrolyzed into CNCs. The FeCl 3 played a dual role, acting both as a cellulose hydrolytic medium and as an Fe 3 O 4 precursor. Subsequently, CNCs served as a stabilizing and sole reducing agent for the in situ formation of Fe 3 O 4 nanoparticles during the solvothermal reaction. The impact of the cellulose substrate, reaction solvent, solvothermal time, and MCC solid-to-liquid ratio on the growth, morphology, and crystal structure of ferrite was investigated. Pure and small sphere-like Fe 3 O 4 (∼30 nm) nanoparticles were successfully immobilized and reduced on the CNC surface when ethanol was used, and the solvent heating time was extended to 3–30 h. Complete reduction of Fe 3+ to Fe 3 O 4 was achieved when the MCC solid to FeCl 3 solution ratio was higher than 1 g:75 mL. Under optimized conditions, the resulting CNC/Fe 3 O 4 hybrid contained 33.3% Fe 3 O 4 and exhibited a maximum saturation magnetization (Ms) value of 22.0 emu/g with low coercivity, making it promising for a wide range of applications.