Unconventional Interconnected High-Entropy Alloy Nanodendrites for Remarkably Efficient C-C Bond Cleavage toward Complete Ethanol Oxidation.

Abstract

Developing ethanol oxidation electrocatalysts with high catalytic activity, durability, and resistance to CO poisoning remains a major challenge. High-entropy alloys (HEAs) with unique physical and chemical properties have garnered substantial attention. Herein, a class of HEA nanodendrites are designed by a simple wet-chemical method. The mass activity and specific activity of the septenary PtIrRhCoFeNiCu high-entropy alloy catalyst are 2.13 A mgPt-1/1.05 A mgPt+Ir+Rh-1 and 2.95 mA cm-2, which reach 5.76-/2.84-fold and 5.57-fold improvements relative to commercial Pt/C (0.37 A mgPt-1 and 0.53 mA cm-2), respectively. Remarkably, after the i-t test of up to 100,000s and the accelerated durability test of 1500 cycles, 81.22% and 68.54% of the initial mass activity are well retained, respectively. The lattice distortion-associated local tensile strain as demonstrated by increased Pt-Pt bond length enhances ethanol adsorption and reduces reaction barriers. The upshift d-band center promotes ethanol oxidation and anti-CO capability of the catalysts. Moreover, hysteresis diffusion effect induced by lattice distortion in the HEA nanodendrites contributes to their superb ethanol oxidation stability. In-situ infrared absorption spectroscopy reveals that the three HEA nanodendrites mainly follow C1 pathway with C-C bond breaking to form CO followed by CO oxidation especially at a wide range of high potentials.