Enhanced electrocatalytic activity of NiWPd nanocrystals for oxygen reduction reaction in fuel cells

The effective inter-conversion of electricity and chemicals via an electrochemical reaction is significant for energy storage devices such as batteries and fuel cells. These fuel cells are regarded as promising solution to energy crisis in 21st century. The slow kinetics of oxygen reduction reaction (ORR) is one of the topmost barriers in this discipline and Pt-based catalysts are needed to boost the durability and activity of ORR. To cope with high cost and less accessibility of Pt/C catalyst, Pd based alloys are being expressed as potential replacements for Pt-based electro catalysts in fuel cells as cathodes for oxygen reduction reaction (ORR). But their performance and stability are less than those of Pt. The morphology and composition can be altered by alloying process to enhance their catalytic properties towards ORR. The present study reports the fabrication of alloys of Pd with tungsten (W) and nickel (Ni) supported on active carbon substrate. The electrocatalysts are studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). Electrochemical investigations confirmed that NiWPd catalysts have improved electro catalytic activities towards oxygen reduction reaction (ORR) with higher specific and mass activities in comparison to Pd/C and Pt/C catalysts. 1.5 % NiWPd/C showed highest ORR performance and mass activity came out to be 2.2mA/cm² that was superior to Pd/C and Pt/C electrocatalysts due to dopants and geometrical impact.