Defect-rich Pt-Ru metallic aerogels for highly efficient ethanol oxidation reaction

Abstract

Direct ethanol fuel cells (DEFCs) are a new type of green and efficient energy conversion devices, but the slow anodic reaction kinetics limit their application. Herein, a series of Pt-Ru metallic aerogels (MAs) with controllable composition, rich surface defects, and large specific surface area were prepared for ethanol oxidation reaction (EOR) by freeze–thaw method. Pt6Ru MAs exhibit the highest mass activity (1.264 A mgPt−1) toward EOR among all the catalysts we have prepared, which is 2.0, 1.8, and 3.7 times higher than those of Pt MAs (0.632 A mgPt−1), the commercial Pt/C (0.696 A mgPt−1), Pt6Ru NPs (0.339 A mgPt−1). 1H nuclear magnetic resonance spectroscopy confirms that only acetic acid was the liquid product of Pt6Ru MAs during EOR catalysis. Furthermore, Pt6Ru MAs show little attenuation and satisfactory reactivation abilities in stability assessment, demonstrating their good stability. This proves that the introduction of Ru makes feasible adjustments to the electronic structure of Pt in MAs, improving the electrocatalysis activity of Pt6Ru MAs in EOR. Mechanistic investigations reveal that the optimal electronic structure is the intrinsic reason for the excellent EOR performance of Pt6Ru MAs. The findings open a new way to develop high-performance Pt-based materials electrocatalysts.