Abstract: Using self-synthesized H?TCA as an organic ligand, a series of bimetallic nanoenzyme materials were successfully synthesized via a solvothermal method by regulating the iron doping ratio. Among these, the Fe?Mn composition exhibited the most optimal peroxidase-like catalytic activity, with a significantly higher catalytic efficiency than single-metal systems and a pronounced composition dependence. Enzyme kinetic analysis revealed that Fe?Mn exhibits exceptional affinity for substrates TMB and H?O?, with corresponding Michaelis-Menten constants (K?) as low as 0.36 mmol/L and 0.1 mmol/L, respectively. Based on the material's outstanding catalytic properties, an “on-off-on” type UV sensing platform was successfully constructed using the acetylcholinesterase-thiocholine cascade reaction. This platform demonstrated excellent analytical performance in methyl parathion detection, with a detection limit as low as 3.04 nmol/L and a linear range spanning 10~330 nmol/L.

Key words: 4,4',4''-Tricarboxytriphenylamine, Nanozymes, Enzyme-like activity, Acetylcholinesterase (AChE), Organophosphorus pesticide detection