Synergistically Enhanced Peroxidase-like Activity of FeSe ₂ /rGO Nanohybrids: Kinetic, Mechanistic, and Molecular Docking Studies

FeSe₂/rGO nanohybrids were prepared via in situ one-pot synthesis using the hydrothermal method and were assessed for their potential for peroxidase-like activity. Structural and morphological analysis using FE-SEM and TEM confirmed the successful in situ growth and uniform distribution of FeSe₂ NPs onto the rGO nanosheet matrix. Furthermore, the FeSe₂/rGO nanohybrids showed superior and enhanced peroxidase-like activities compared to the bare FeSe₂, as demonstrated using two substrates, 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD). Michaelis-Menten kinetics showed a significantly lower Km of 0.00952 mM for TMB and 7.62 mM for H₂O₂, along with a high Vmax of 6.48 × 10⁻⁸ M s⁻¹ (TMB) and 1.706 × 10⁻⁶ Ms⁻¹ (H₂O₂) for FeSe₂/rGO, outperforming bare FeSe₂ and several other reported nanozymes. The kinetic parameters showed a strong substrate affinity and improved catalytic efficiency. Mechanistic study using terephthalic acid (fluorescent probe) revealed that •OH is majorly responsible for substrate oxidation, which is significantly enhanced by the synergistic effect of FeSe₂ and rGO. Furthermore, in support of our experimental results, molecular docking studies with multiple peroxidase proteins also showed significantly higher binding affinities for FeSe₂/rGO (-9.9 to -11.9 kcal mol⁻¹), as compared to FeSe₂ (-4.8 to -9.1 kcal mol⁻¹). Overall, this work highlights FeSe₂/rGO as a robust peroxidase mimic and efficient nanozyme with strong potential for colorimetric sensing and catalytic performance.