Owing to their high energy efficiency, reduced pollution, and minimal maintenance cost, fuel cells have been regarded as one of the most promising energy conversion devices. The commonly used effective electrocatalysts are platinum-based materials. The development of fuel cell electrodes with non-noble metal catalysts to lessen the use of Pt-based materials has been the focus of this study. The cathode catalysts were synthesized using the sodium borohydride reduction method. Catalyst inks were prepared and subjected to electrochemical characterization that included linear sweep voltammetry (LSV) and cyclic voltammetry (CV). Optimization of the metal loading and metal salt shows that the non-precious metal catalyst, 20% cobalt porphyrin (2,3,7,8,12,13,17,18-Octaethyl-21H, 23H-porphine cobalt (II)) supported on carbon black (CoP/C), gave the highest catalytic activity having a current density of 2.23 mA cm -2 compared to the commercially available 20% Pt/C (Premetek, USA) (1.46 mA cm -2 ) in basic medium. The retained current for the CoP/C was 58.15% while for the 20% Pt/C catalyst (Premetek (USA), it was 21.23%. The electrochemical impedance spectroscopy (EIS) showed enhanced electron transfer kinetics for CoP/C than the commercially available 20% Pt/C (Premetek, USA). The morphological and surface characterization were obtained using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis that confirmed the ~20% metal loading of the catalyst.
In this research, polyaniline/Fe/graphene oxide (PANI/Fe/GO) and polyaniline/Fe/carbon black (PANI/Fe/CB) composites were chemically synthesized as cathode catalyst for oxygen reduction reaction. Surface and elemental characterization of the synthesized composites were done using scanning electron microscopy (SEM), Atomic force microscopy (AFM) and energy dispersive X-ray (EDX) analysis. Elemental analysis confirms the Fe metal content of the catalyst. SEM images of PANI presents globular microstructures while GO on the other hand displays sheet-like structure with a height of 0.889 nm based on AFM results. The electrocatalytic activity of the prepared Fe based catalyst composites was evaluated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and Chronoamperometry in 0.5 M sulfuric acid purged with oxygen for 5 min. Electrochemical characterization shows the electrocatalytic activities of PANI/Fe/CB with a current density of 3.98 mA/cm 2 and PANI/Fe/GO with a current density of 7.13 mA/cm 2 . Chronoamperometric investigations illustrate that Pt/C gave a more stable curve compared to PANI/Fe/GO. In comparison with the commercially available Pt/C catalyst with a current density of 0.99 mA/cm 2 , it can be seen that the synthesized PANI/Fe/GO and PANI/Fe/CB composites gave higher current densities compared to the commercially available platinum/ carbon (Pt/C) indicating that these catalyst composites could be a promising catalyst for ORR.
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