Engineering Heterogeneous Synergistic Interface and Multifunctional Cobalt-Iron Site Enabling High-Performance Oxygen Evolution Reaction

It has been extensively researched that oxygen evolution reaction (OER) in alkaline conditions involves dynamic surface restructuring. In particular, the development and design of sulfide/oxide pre-catalyst can reasonably adjust the composition and structure after surface reconstruction, which is very important for oxygen evolution reaction. Herein, a simple two-step hydrothermal method was used to achieve in situ S leaching and doping by precipitation-dissolution equilibrium, inducing the composition change and structure reconstruction of CoFe oxides. In addition, the cross-linked nanosheet structure generated in situ widely exposes the active area, and the crystal/amorphous interface accelerates the charge and mass transfer efficiency. The structurally transformed FeOOH and CoOOH showed excellent OER activity, with overpotentials of 299 and 322.2 mV at 50 and 100 mA cm-2, significantly superior to one-step or uncured catalysts. Low-cost iron based materials combined with simple methods can be easily mass-produced. This provides an opportunity for the effective design of heterogeneous surface reconfigurable electrocatalysts for practical water electrolysis.