PtIrFeCoNiMo high-entropy alloy nanodendrites for boosting the alkaline hydrogen oxidation performance

Developing highly active electrocatalysts for the hydrogen oxidation reaction (HOR) is crucial for practical application in fuel cells. Here, novel PtIrFeCoNiMo high entropy alloy nanodendrites (HEA NDs) were synthesized by a wet-chemistry method for enhancing alkaline HOR. The mass activity (jk,m) of HEA NDs can reach as high as 3.53 mA gPGM-1, which is about 1.7 and 14 times higher than those for PtIrFeCoNiMo nanoparticles (2.07 mA gPGM-1) and commercial Pt/C (0.25 mA gPGM-1). They also show high specific activity, excellent long-term stability and superior anti-CO ability. Combining DFT calculations, the enhancement of alkaline HOR could be attributed to weakened hydrogen binding energy and enhanced hydroxyl binding energy, which are regulated by the synergistic electron effect of these metals in high entropy alloy nanodendrites. This work paves an avenue for the fabrication of high-entropy catalysts with excellent performance for the HOR. PtIrFeCoNiMo HEA NDs show excellent alkaline HOR performance due to optimizing the HBE and OHBE by the synergistic high-entropy effect.