While morphological control in metal-organic frameworks (MOFs) has been widely explored, the extension of this concept to compositional engineering and precise anisotropic growth in high-entropy systems has only recently emerged. Herein, we present the first synthesis of one-dimensional single-crystal HE-MOF-74 nanorods (comprising Co, Fe, Ni, Zn, and Mo) via a dual strategy, where zinc-directed anisotropic growth occurs exclusively on a graphene oxide support. In situ Raman spectroscopy combined with molecular probe electroanalysis and DFT analysis reveal two simultaneous catalytic pathways. (i) The oxophilic Mo promotes the adsorbate evolution mechanism (AEM) with Ni centers (Ni-Ni*-Mo), (ii) Zn enhances the covalency of the M-O bonds, specifically favoring Fe-O/Co-O covalency to activate the lattice-oxygen-mediated mechanism (Co/Fe-O*-Zn). This synergistic dual-pathway mechanism in the HE-MOF nanorod is directly responsible for the exceptional electrocatalytic performance, which includes an ultralow OER overpotential of 220 mV and remarkable stability sustained for 250 h at a high current density of 100 mA cm-2. It also demonstrates superior performance for urea (UOR, 1.32 V at 10 mA cm-2), ethanol (EOR, 1.31 V at 10 mA cm-2), and methanol (MOR, 1.355 V at 10 mA cm-2) oxidation reactions, significantly outperforming its lower-entropy counterparts. This work demonstrates how Zn ions, supported by graphene oxide, play a crucial role in directing anisotropic growth in high-entropy systems, while simultaneously activating dual-mechanistic pathways to synergistically enhance multianodic reactions.
Kumar et al. (Mon,) studied this question.