La-exacerbated lattice distortion of high entropy alloys for enhanced electrocatalytic water splitting

The complex active site configurations of high entropy alloys (HEAs) limit their performance optimization and wide applications. Herein, we report a FeCoNiMnRuLa/CNT catalyst for efficient electrocatalytic water splitting by introducing La to break the lattice ordering of FeCoNiMnRu. The introduction of La reduces the number of unpaired electrons in FeCoNiMnRu, which in turn accelerates the transition of singlet state oxygen-containing intermediate to triplet state oxygen. The DFT results verify that the lattice distortion exacerbated by La alters the d-orbital electronic configuration of FeCoNiMnRu, so that Fe and Ni play an important role in the critical adsorption of *OH in the OER as well as *HO in the HER, and Ru, Co, and Mn provide a strong safeguard for the desorption of oxygen-containing intermediates, thereby retaining excellent activity and stability during water decomposition. Our work showcases that the incorporation of rare earth elements opens new opportunities to improve the performance of HEAs.