Non-precious and accessible nanocomposite of iron oxide on PDDA-Modified graphene for catalyzing oxygen reduction reaction

Nanocomposite catalysts composed of non-precious nanoparticles anchored by modified graphene for oxygen reduction reactions (ORRs) are the emphasis of research nowadays for wide application in electrocatalyst systems. Herein, an endeavor is made to report on a one-pot synthesis method to produce a catalyst for Fe₃O₄ and Ni–NiO nanoparticles on Polydiallyldimethylammonium chloride-modified graphenes (PDDA-G). The nanocomposite is characterized by spectral measurements, using scanning electron spectroscopy (SEM), transmitting electron spectroscopy (TEM), x-ray diffractometer (XRD) and Raman spectroscopy to reveal its microstructure. Through a layer-by-layer PDDA-G investigation, a significant anchoring of nanoparticles and maintenance of the graphene with good electron transporting properties and spatial distance in nanoscale by PDDA is achieved. Additionally, the electrochemical properties of Fe₃O₄@PDDA-G and Ni–NiO@PDDA-G are demonstrated by linear scan voltammetry (LSV) with rotation disk electrode (RDE). Fe₃O₄@PDDA-G displays prominent ORR activity in 2-electron and 4-electron pathways, and better ORR mass activities than Ni–NiO@PDDA-G and commercial Pt/C. The results of this study provide a new strategy to develop material design approaches for high-performance electrocatalysts to be employed in fuel cells.