Dinitrosyl Iron Complex-Derived Nanosized Zerovalent Iron (NZVI) as a Template for the Fe-Co Cracked NZVI: An...

Nanosized zerovalent iron (NZVI) Fe@FeO with a core-shell structure derived from photocatalytic MeOH aqueous solution of dinitrosyl iron complex (DNIC) [(N₃MDA)Fe(NO)₂] (N₃MDA = N,N-dimethyl-2-(((1-methyl-1H-imidazole-2-yl)methylene)amino)ethane-1-amine) (1-NMDA), eosin Y, and triethylamine (TEA) is demonstrated. The NZVI Fe@FeO core shows a high percentage of zerovalent iron (Fe⁰ %) and is stabilized by a hydrophobic organic support formed through the photodegradation of eosin Y hybridized with the N₃MDA ligand. In addition to its well-known reductive properties in wastewater treatment and groundwater remediation, NZVI demonstrates the ability to form heterostructures when it interacts with metal ions. In this research, Co²⁺ is employed as a model contaminant and reacted with NZVI Fe@FeO to result in the formation of a distinct Fe-Co heterostructure, cracked NZVI (CNZVI). The slight difference in the standard redox potentials between Fe²⁺ and Co²⁺, the magnetic properties of Co²⁺, and the absence of surface hydroxides of Fe@FeO enable NZVI to mildly reduce Co²⁺ and facilitate Co²⁺ penetration into the iron core. Taking advantage of the well-dispersed nature of CNZVI on an organic support, the reduction in particle size due to Co²⁺ penetration, and Fe-Co synergism, CNZVI is employed as a catalyst in the alkaline oxygen evolution reaction (OER). Remarkably, CNZVI exhibits a highly efficient OER performance, surpassing the benchmark IrO₂ catalyst. These findings show the potential of using NZVI as a template for synthesizing highly efficient OER catalysts. Moreover, the study demonstrates the possibility of repurposing waste materials from water treatment as valuable resources for catalytic energy conversion, particularly in water oxidation processes.