Zn-Leaching Induced Rapid Self-Reconstruction of NiFe-Layered Double Hydroxides for Boosted Oxygen Evolution Reaction

Optimizing the active centers through reconstruction is recognized as the key to construct high-performance oxygen evolution reaction (OER) catalysts. Herein, a simple and rapid in situ leaching strategy to promote the self-reconstruction of NiFe-layered double hydroxides (LDHs) catalysts is reported. The trace Zn dopants are introduced in advance by a facile and one-step hydrothermal method, followed by leaching over the electrochemical activation process, which can remarkably reduce the formation potential of NiFeOOH active centers to enable the deeper self-reconstruction for the formation of abundant highly active centers. Moreover, the self-restructured NiFeOOH-VZn cannot only significantly lower the dehydrogenation energy barrier for the transformation from Ni(OH)2 to NiOOH, but also decrease the free energy barrier of rate determining step for the *OH converted to *O through a deprotonation process, thus significantly boosting the OER behaviors. As a proof of concept, the obtained NiFeOOH-VZn catalyst just requires a low overpotential of 240 mV at 10 mA cm-2, and delivers robust stability at 50 mA cm-2 over 120 h, which outperforms the benchmark of noble metal RuO2 and those of most non-noble metal catalysts ever reported. This work reported a simple and rapid strategy to promote self-reconstruction and form highly active NiFeOOH centers, by introducing Zn beforehand and allowing it to leach via rapid electrochemical activation. The self-restructured NiFeOOH-VZn catalysts show excellent OER activity with a low overpotential of 240 mV at 10 mA cm-2 and excellent durability at 50 mA cm-2 over 120 h.image

Automated summary

This study reports a simple and rapid method to promote self-reconstruction of NiFe-layered double hydroxides (LDHs) catalysts, leading to the formation of highly active centers. The introduction of zinc and its leaching through electrochemical activation significantly improves the OER performance.