Ultrafine platinum-iridium distorted nanowires as robust catalysts toward bifunctional hydrogen catalysis

Abstract

Robust platinum (Pt)-based nanocatalysts exhibit hydrogen catalysis activities but their slow kinetics in alkaline medium is still a crucial problem for fuel cells and water electrolysis. Here, we report a class of Pt–iridium distorted nanowires (Pt–Ir DNWs) in the sub-nanometer scale as bifunctional catalysts for the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR). The optimized Pt₂Ir DNWs/C not only showed a low overpotential and small Tafel slope for HER but also achieved the best HOR performance in which the mass activity and specific activity were 12.4/15.7 and 6.2/5.1 times higher than those of commercial Pt/C and Pt DNWs/C, respectively. Moreover, they exhibited superior stability and anti-CO poisoning ability for HOR. It was demonstrated that the distorted nanowire structure and balanced H and OH adsorption energy regulated by the electronic structure were crucial to the HOR performance improvement for the Pt₂Ir DNWs. This work provides a new perspective for designing advanced bifunctional hydrogen catalysts.