Study on the structure and electrocatalytic activity of graphene-based nanocomposite materials containing (SCN)n

Novel graphene-based nanocomposite material was prepared in order to fabricate superior metal-free catalyst for oxygen reduction. The nanocomposite was synthesized by a facile and cost-effective solid-solid reaction between GO and KSCN, where the thiocyatate fragments undergo polymerization. The structure of polythiocyanogen (SCN)n in this nanocomposite was compared to the structure of (SCN)n prepared by different methods. The structural characterization of synthesized polymers was performed using SEC, XRD, SEM, FTIR, TGA/DTG, XPS, and elemental analysis. It was determined that the structure of polymer is characterized by polyazomethine chains. The solid-solid reaction between GO and KSCN occurs on the edges of GO to form a characteristic curled morphology, which emerges due to the attachment of short oligomeric (SCN)n chains at the edges of GO. The curled structure is beneficial for the adsorption of small molecules and ions. The linear sweep voltammetry measurements revealed remarkable catalytic performance towards oxygen reduction reaction (ORR) of product the nanocomposite material. In acidic media efficiency of ORR on the nanocomposite material was ∼5 times higher compared to that of commercial catalyst. Investigation of the mechanism of ORR onto the nanocomposite indicated that the protonated nitrogen atoms in oligomer active sites can act as catalysts.

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