Incorporating Au atoms: A highly effective strategy to unlock enhanced activity and durability for alkaline methanol electrooxidation on PtPdCuCoNiAu high-entropy alloy through the formate pathway.

The poor durability and insufficient activity of platinum-based catalysts, caused primarily by intermediate poisoning and structural degradation, are major obstacles to direct methanol fuel cells. In this study, we demonstrate that the strategic doping of Au atoms into a PtPdCuCoNi high-entropy alloy (HEA) aerogel effectively addresses these dual challenges. The incorporation of Au induces lattice strain and modulates the electronic structure, as confirmed by X-ray diffraction and photoelectron spectroscopy. This electronic redistribution results in a downshift of the d-band center, which optimizes the adsorption energy of key intermediates. Electrochemically, the Au-doped PtPdCuCoNi HEA aerogel exhibits exceptional activity for the alkaline methanol oxidation reaction (MOR), achieving a mass activity of 16.38 ± 0.61 A mg-1Pt and a specific activity of 75.89 ± 1.21 mA cm-2, surpassing its Au-free counterpart and commercial Pt/C by factors of 1.5/4.0 and 1.2/9.4, respectively. More importantly, the catalyst shows significantly enhanced durability, a performance markedly superior to its Au-free counterpart. In situ infrared spectroscopy reveals that Au doping steers the MOR pathway towards direct formate oxidation, effectively suppressing the formation of CO poisoning species. In direct methanol fuel cell environment, the PtPdCuCoNiAu HEAAs achieved a peak specific power of 308.2 mW/mgPt, exceeding the data reported in current literatures. This work highlights the critical role of targeted element doping in designing high-entropy alloy catalysts with combined high activity and durability for advanced energy conversion.