Sub‐2 nm Ultrathin and Robust 2D FeNi Layered Double Hydroxide Nanosheets Packed with 1D FeNi‐MOFs for Enhanced Oxygen Evolution Electrocatalysis

Abstract Water oxidation is a critical process for electrochemical water splitting due to its inherent sluggish kinetics. In spite of the high catalytic activities of noble metal‐based electrocatalysts for water oxidation, their high cost, rare reserves, and low stabilities drive researchers to exploit efficient but low‐cost electrocatalysts. Ultrathin 2D nanomaterials are considered efficient electrocatalysts for oxygen evolution reaction (OER) in water splitting. Herein, a facile strategy is proposed to fabricate 2D FeNi layered double hydroxide (FeNi‐LDH) nanosheets packed with the in situ produced 1D sword‐like FeNi‐MOFs by using FeNi‐LDH as a semi‐sacrificial template. In the composite, the thickness of the formed nanosheets is only 1.34 nm, much thinner than that of most previously reported 2D materials. The 1D porous sword‐like MOF nanorods have a long length of around 1.3 µm. Due to the unique 2D/1D combined structure, the as‐prepared FeNi LDH/MOF is directly used as electrocatalyst for the OER displays enhanced OER electrocatalytic performance with a low overpotential of 272 mV@100 mA cm –2 , a small Tafel slope of 34.1 mV dec –1 , high long‐term durability. This work provides a new way to fabricate integrated ultrathin 2D nanosheets and MOFs as advanced catalysts for electrochemical energy conversion.