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Abstract
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Polyaniline-Silica (PANI-SiO2) nanocomposite was developed as a support for enhancing the performance of Pt/Ni electrocatalyst in direct methanol fuel cells (DMFCs). Bimetallic Pt/Ni electrocatalyst was deposited on the in-situ prepared PANI-SiO2 nanocomposite via cyclic voltammetry (CV) method. The electro-oxidation of methanol was studied at room temperature using CV, linear sweep voltammetry (LSV), and chronoamperometry (ChA) tests. The Pt/Ni/SiO2-PANI electrocatalyst resulted in an onset potential of −0.54 V and an excellent peak current density of 144 mA/cm2 showing its outstanding catalytic activity. Moreover, the Pt/Ni/SiO2-PANI electronic structure was theoretically investigated via density functional theory (DFT) calculations. The DFT results confirmed that employing the PANI-SiO2 structure for bimetallic PtNi nanostructure could lead to increasing the reactivity of the resulting catalyst and decreasing the energy gap. This observation was well consistent with the experimental results. The experimental and theoretical data indicated that PANI-SiO2, as an organic-inorganic hybrid catalyst support, considerably improved the stability and CO poisoning tolerance of the resulting electrocatalyst, both of which are crucial for practical alkaline direct methanol fuel cell applications.
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