Formicary-like PtBi1.5Ni0.2Co0.2Cu0.2 high-entropy alloy aerogels as an efficient and stable electrocatalyst for methanol oxidation reaction

High-entropy alloy aerogels (HEAAs) have become promising electrochemical catalysts because of the advantageous combination of high-entropy alloys and aerogel structure. However, how to fabricate 3D porous high-entropy alloys accurately is still a great challenge due to their inherent thermodynamic instability and differences in reduction potentials of metal ions. Herein, PtBi 1.5 Ni 0.2 Co 0.2 Cu 0.2 HEAAs have been synthesized by combining co-reduction method and freeze-drying technology. The resulting PtBi 1.5 Ni 0.2 Co 0.2 Cu 0.2 HEAAs have the structural and morphological benefits of both high-entropy alloys and aerogels. Both XPS and DFT results confirm that the d-band center of PtBi 1.5 Ni 0.2 Co 0.2 Cu 0.2 HEAAs shifts to lower binding energy compared to Pt/C, indicating the effective regulation of electronic structure on the surface of PtBi 1.5 Ni 0.2 Co 0.2 Cu 0.2 HEAAs. As a demonstration in the methanol oxidation reaction (MOR), a mass activity of 4.19 A mg Pt −1 and long-term stability (>0.33 A mg Pt −1 after 10 cycles of 3600 s stability test) can be obtained on the PtBi 1.5 Ni 0.2 Co 0.2 Cu 0.2 HEAAs, outperforming binary Pt-based alloys and commercial Pt/C. The CO adsorption strength of PtBi 1.5 Ni 0.2 Co 0.2 Cu 0.2 HEAAs is more weaker than that of PtBi 1.5 alloys and Pt/C, which proves the enhanced CO tolerance. The results pave the way for fabricating the hybrids of high-entropy alloys and aerogels with superior activity and stability.