Ultrafast Electrodeposition of Ni−Fe Hydroxide Nanosheets on Nickel Foam as Oxygen Evolution Anode for Energy‐Saving Electrolysis of Na2CO3/NaHCO3

Nickel/iron (Ni−Fe)‐based compounds are known as active electrocatalysts for the oxygen evolution reaction (OER), which plays an important role in metal−air batteries and water splitting. Herein, a three‐dimensional (3D) porous nickel foam electrode (NiFe(OH)x NSs/Nif) modified with Ni−Fe hydroxide nanosheets (NSs) is prepared by using a fast and facile electrodeposition method. The electrode is subsequently applied in the electrolysis of Na2CO3/NaHCO3 to produce hydrogen, oxygen, NaOH, and NaHCO3/CO2. By carefully controlling the electrodeposition time, ultrathin NiFe(OH)x NSs with a thickness of approximately 2–6 nm are interlaced with one another and grown vertically on nickel foam to form a hierarchical composite electrode. The prepared NiFe(OH)x NSs/Nif electrode exhibits superb OER performance with an overpotential of 260 mV at 10 mA cm−2 and a low Tafel slope of 29 mV dec−1 in 1 mol L−1 NaOH solution. In 0.5 mol L−1 Na2CO3/NaHCO3 solution, the NiFe(OH)x NSs/Nif electrode exhibits a low OER potential of 290 mV, which is lower than the commercial RuO2/Ti electrode at a current density of 100 mA cm−2, and shows good long‐term stability. During electrolysis of Na2CO3/NaHCO3, the cell voltage with the NiFe(OH)x NSs/Nif anode is 2.52 V, which is 280 mV lower than that with a commercial RuO2/Ti anode. Cat. on the job: A 3D porous nickel foam electrode (NiFe(OH)x NSs/Nif) is modified with Ni−Fe hydroxide nanosheets (NSs) is prepared by using a fast and facile electrodeposition method. The prepared NiFe(OH)x NSs/Nif electrode exhibits superb oxygen evolution reaction performance and shows a good long‐term stability. In the electrolysis of Na2CO3/NaHCO3, the cell voltage with a NiFe(OH)x NSs/Nif anode is 2.52 V, which is 280 mV lower than that with a commercial RuO2/Ti anode.