Nanocomposite oxygen reduction electrocatalysts formed using bioderived reducing agents

Crystalline cellulose nanofibrils from cotton were used as reducing agents for the synthesis of nanostructured silver. The hydrothermal synthesis involved heating an AgNO3 solution containing suspended cellulose nanofibrils at 80 degrees C for 2 h. The formation of metallic silver was verified using UV/Visible spectroscopy, X-ray diffraction and transmission electron microscopy (TEM). Cellulose/silver nanocomposite films were formed at glassy carbon surfaces by drop coating with the product suspension and scanning electron microscopy (SEM) was used to characterise the modified surfaces. The film morphology depended on the ratio of silver to cellulose in the films. Cyclic voltammetry and rotating-disk electrode voltammetry were used to study the electrochemical and electrocatalytic behavior of these films. The nanocomposite films formed using this approach were highly active electrocatalysts for the reduction of oxygen in alkaline media.