Development of nanostructured Pt-based catalysts for fuel cell applications has urged great interest in the last decades [1]. Herein, we reported the synthesis of PtIr nanodendrites (NDs) for methanol oxidation reaction (MOR). This was performed through a one-pot one-step procedure by reduction of the metal precursors using ascorbic acid in the presence of pluronic F127 as a structure-modifying agent. The as-synthesized nanocrystals (NCs) revealed nanodendritic morphology with an average size of 30 nm. PtIr NDs depicted a small strain value of 0.17 % owing to the similar crystal structures and similar atomic radii of Pt and Ir. The prepared binary NCs exhibited electrochemical surface area (ECSA) of 77.5 m2 g-1 which is higher than that of Pt NCs (68.2 m2 g-1) and Pt/C (52.1 m2 g-1 ). PtIr NDs expressed enhanced catalytic activity towards MOR in acid medium with the mass activity of 527 mA mg-1 which is 2.1 and 3.6 times greater than that of Pt NDs and Pt/C, respectively. In addition, the binary nanocatalyst exhibited enhanced electrochemical stability compared to its counterparts where it maintained 86% of its initial activity after 1000 durability cycles, whereas Pt NDs and Pt/C reserved about 78% and 71% of their initial activities, respectively. The superior catalytic performance of PtIr compared to monometallic electrocatalysts was attributed to the modulation of the d-band center, which decreases the adsorbability of poisoning species [2]. What is more, Ir enhances the adsorption of oxygenated species, which facilitates the oxidation of CO-like species and enhances poisoning tolerance.

Facile one-pot synthesis of PtIr nanodendrites for electrochemical methanol oxidation

ACS Spring Meeting 2021

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