Five-fold twinned Ir-alloyed Pt nanorods with high C1 pathway selectivity for ethanol electrooxidation

摘要

Developing efficient and robust electrocatalysts toward ethanol oxidation reaction (EOR) with high C1 pathway selectivity is critical for commercialization of direct ethanol fuel cells (DEFCs). Unfortunately, current most EOR electrocatalysts suffer from rapid activity degradation and poor C1 pathway selectivity for complete oxidation of ethanol. Herein, we report a novel electrocatalyst of five-fold twinned (FFT) Ir-alloyed Pt nanorods (NRs) toward EOR. Such FFT Pt-Ir NRs bounded by five (100) facets on the sides and ten (111) facets at two ends possess high percentage of (100) facets with tensile strain. Owing to the inherent characteristics of the FFT NR and Ir alloying, the as-prepared FFT Pt-Ir NRs display excellent alkaline EOR performance with a mass activity (MA) of 4.18 A center dot mg(Pt)(-1), a specific activity (SA) of 10.22 mA center dot cm(-2), and a Faraday efficiency of 61.21% for the C1 pathway, which are 6.85, 5.62, and 7.70 times higher than those of a commercial Pt black, respectively. Besides, our catalyst also exhibits robust durability. The large percentage of open tensile-strained (100) facets and Ir alloying significantly promote the cleavage of C-C bonds and facilitate oxidation of the poisonous intermediates, leading to the transformation of the dominant reaction pathway for EOR from C2 to C1 pathway, and effectively suppress the deactivation of the catalyst.

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