Affiliation:
1. Beijing Key Laboratory of Bioprocess College of Life Science and Technology Beijing University of Chemical Technology Beijing 100029 China
2. Institute of Modern Optics and Center of Single-Molecule Science Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Nankai University Tianjin 300350 China
3. College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China
Abstract
AbstractDesigning metal nanoparticles with oxidase‐mimicking capabilities has garnered significant attention due to their promising attributes. However, understanding the intricate catalytic mechanisms underlying these nanoparticles poses a formidable challenge. In this study, a straightforward pyrolysis procedure was employed to synthesize nitrogen‐doped iron‐based nanoparticles (Fe NPs‐N@C) with Fe8−N2 serving as active sites. The confirmation of these sites was thoroughly confirmed through density functional theory (DFT) calculations complemented by experimental validation. The resulting Fe NPs‐N@C nanoparticles, averaging 5.45 nm in size, exhibited excellent oxidase‐mimicking activity, with vmax=1.11×10−7 M s−1and km=1.67 mM, employing 3,3′,5,5′‐tetramethylbenzidine as a substrate. The oxidation pathway and catalytic mechanism of Fe NPs‐N@C involved 1O2⋅ radicals, validated through electron paramagnetic resonance analysis and DFT calculations. Furthermore, Fe NPs‐N@C/TMB system was devised for ascorbic acid and nitrite quantitative detection. This method demonstrated the capability to detect ascorbic acid within concentrations ranging from 1 to 55 μM, with a limit of detection (LOD) of 0.81 μM, and nitrite within concentrations from 1 to 160 μM, with a LOD value of 0.45 μM. These findings offer a comprehensive understanding of the catalytic mechanisms of Fe NPs‐N@C nanoparticles at the atomic level, along with its potential for colorimetric sensor in future.
Funder
National Natural Science Foundation of China