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

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 FeCo 2 S 4 hollow nanoneedle decorated with MoO 3 nanoparticles (MoO 3 @FeCo 2 S 4 ) 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-MoO 3 . 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 MoO 3 @FeCo 2 S 4 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.