Oxidation of formic acid over palladium catalyst supported on activated carbon derived from polyaniline and modified lignosulfonate composite

Activated carbons (AC) were obtained through carbonization of polyaniline and modified lignosulfonate composite (PAn-MLS) under different temperatures; they are characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, nitrogen sorption and scanning electron microscope (SEM). With these carbon materials as the support, a series of Pd-AC catalysts for the oxidation of formic acid were prepared by liquid phase reduction and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and electrochemical analysis. The results show that with the activated carbon prepared at 800°C (AC800) as the support, the Pd-AC800 catalyst obtained performs best in the oxidation of formic acid; the palladium particles have an average size of 5.4 nm and the electro-active surface area reaches 53.78 m2/g. As the oxidation of formic acid over Pd-AC800 is realized through direct pathway rather than CO pathway, Pd-AC800 may be considered as a potential electrode material in direct formic acid fuel cells (DFAFC).