NiFeS 2 Nanozymes Derived From Ni–Fe Layered Double Hydroxide Precursor Using Thermal Decomposition Method: A Study on Their Peroxidase‐Mimicking Properties
Sanjna Sahu, Pethaiyan JeevanandamABSTRACT
In the present work, NiFeS 2 nanoparticles were synthesized using NiFe‐LDH (layered double hydroxide) as a precursor via a thermal decomposition method. The NiFe‐LDH was converted into NiFeS 2 nanoparticles at 200°C in diphenyl ether or 1‐octadecene using two different sulfur sources (thioacetamide and thiourea). The formation of pure pyrite phase of NiFeS 2 nanoparticles was proved by powder X‐ray diffraction, while transmission electron microscopy (TEM) studies revealed nearly spherical, and well‐dispersed NiFeS 2 nanoparticles. X‐ray photoelectron spectroscopy proved the presence of Ni 2+ , Ni 3+ , Fe 3+ , and S 2 2– in the NiFeS 2 nanoparticles. Optical characterization, using UV–vis diffuse reflectance spectroscopy, revealed that the NiFeS 2 nanoparticles possess a narrow band gap (1.30–1.46 eV). The magnetic properties of NiFeS 2 nanoparticles reveal paramagnetic behavior at 300 K and weak ferromagnetic characteristics at 5 K. Notably, the NiFeS 2 nanoparticles exhibit intrinsic peroxidase‐like activity. Under the experimental conditions employed in the present study, the NiFeS 2 nanoparticles show enhanced catalytic efficiency compared to natural HRP and reported analogous nanozymes. Among the synthesized NiFeS 2 nanoparticles, the NFS‐DPE‐TAA exhibits superior catalytic activity and demonstrates its applicability as a nanozyme‐based colorimetric probe for H 2 O 2 sensing.