Rapid mass production of iron nickel oxalate nanorods for efficient oxygen evolution reaction catalysis

Abstract

The NiFe layered-double-hydroxide (NiFe-LDH) and the NiFe metal–organic framework (NiFe-MOF) demonstrate the best catalytic activity among NiFe-based materials for the oxygen evolution reaction (OER), which is important for efficient hydrogen production. However, the preparation processes of these materials are usually cumbersome and have a low yield, which eliminates their most critical advantage of being low cost. We propose a method for rapidly and efficiently preparing porous (Ni_0.5Fe_0.5)C₂O₄ nanorods with an excellent OER catalytic performance. The overpotential of (Ni_0.5Fe_0.5)C₂O₄ is 266 mV at 20 mA cm⁻² under alkaline conditions, and the Tafel slope is 54.39 mV dec⁻¹. Furthermore, analysis of the changes in the surface properties of the material before and after catalysis determined that the real active material is (Ni_0.5Fe_0.5)(OH)_x(C₂O₄)_1−x. Using a simple scaled-up experiment, (Ni_0.5Fe_0.5)C₂O₄ is mass-produced (40 g) via direct synthesis in 5 min. The composition and performance of the mass-produced sample are analysed under the same conditions, and (Ni_0.5Fe_0.5)C₂O₄ still has a good catalytic performance and its composition has not changed. The efficient synthesis of (Ni_0.5Fe_0.5)C₂O₄ nanorods with a porous structure provides a new option for the development of commercial catalysts using non-precious metals.