Superior Electrochemical Oxygen Evolution Enabled by Three‐Dimensional Layered Double Hydroxide Nanosheet Superstructures

Abstract Although extensive efforts have been devoted to the pursuit of promising electrocatalysts to lower the overpotential of the oxygen evolution reaction (OER), the design of low‐costing earth‐abundant OER electrocatalysts with desirable performance remains a formidable challenge. Herein, we demonstrate a facile strategy to create ultrathin NiFe layered double hydroxide (LDH) nanosheets grown on carbon nanotubes (CNTs) as superior OER electrocatalysts. Different from previously reported NiFe‐LDH nanomaterials, the newly generated NiFe‐LDH@CNTs exhibit distinct features, including ultrathin building blocks, a 1 D structure, 3 D hierarchical architecture, and the electron effect. Significantly, it was revealed that doping Fe into Ni‐LDH@CNTs optimized the performance for the OER; Ni 8 Fe‐LDH@CNTs was found to be the most active and is one of the best non‐noble metal catalysts for the OER to date. The catalysts are also highly stable for the OER with little potential shift after an 18 h test. Both X‐band electron spin resonance and X‐ray photoelectron spectroscopy indicated that optimized iron doping resulted in intense interaction between Ni x + and Fe 3+ and electron transfer from Ni x + to Fe 3+ , which thus boosted the OER performance.