Promoting Surface Reconstruction with a Tip-Enhanced Local Field and Electronic Interaction for Efficient Oxygen...

The rational regulation of the surface reconstruction in transition-metal-based electrocatalysts to optimize the catalytic performance for the oxygen evolution reaction (OER) is increasingly important yet remains challenging. Herein, we develop a strategy of the electronic interaction and tip-enhanced local field to synergistically tune the surface reconstruction. As a demonstration, a heterostructure catalyst comprising an FeCo₂S₄ hollow nanoneedle decorated with MoO₃ nanoparticles (MoO₃@FeCo₂S₄) at the tip is constructed. The combined theoretical and in situ X-ray absorption investigations indicate that the abundant Co-O-Mo motifs at the interface improve the electron transfer, facilitating the surface reconstruction into Co(Fe)OOH-MoO₃. Meanwhile, the sharp tip of the hollow nanoneedles enhances the local electric field and increases the pH near the tip to promote the formation of active CoOOH. Accordingly, the as-constructed MoO₃@FeCo₂S₄ shows a low overpotential of 277 mV at a current density of 100 mA cm^-2 during the alkaline OER and maintains stable operation at 200 mA cm^-2 for 100 h. This work not only provides insights for the rational regulation of surface reconstruction but also highlights the important integration of the electronic interaction with a local environment to design advanced transition-metal-based catalysts.