Rational Design of Fe<sub>1</sub>–Co<sub>1</sub>/NC Diatomic Nanozyme-Based Electronic Tongues: Discriminating Active Substances in Licorice
Jingyuan Guo, Ziyue Wang, Wang Guo, Yujia Liu, Shuang Liang, Bo Peng, Weifeng Huang, Zhengbo Chen
Abstract
Herein, by the pyrolysis and alkali leaching of zeolitic imidazolate framework-8 (ZIF-8)@SiO 2, followed by Fe and Co doping, a novel Fe 1 Co 1 /NC nanozyme, with adjacent Fe and Co dual-atom pairs decorated on an N-doped carbon support, is exactly built. Due to the synergistic effect of adjacent Fe and Co dual-atom pairs, the peroxidase-like activity of Fe 1 Co 1 /NC is significantly enhanced, far exceeding those of Fe 1 /NC and Co 1 /NC. Based on this, we propose a simple colorimetric electronic tongue consisting of Fe 1 Co 1 /NC, chromogenic substrates (3,3′,5,5′-tetramethylbenzidine) (TMB), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and o -phenylenediamine (OPD) and H 2 O 2 to identify seven active substances in licorice. The mechanism of action of this tongue is that different active substances have differential degrees of inhibition on the three nanozyme-catalyzed reactions (Fe 1 Co 1 /NC-TMB-H 2 O 2, Fe 1 Co 1 /NC-ABTS-H 2 O 2, and Fe 1 Co 1 /NC-OPD-H 2 O 2 ). The collected absorbance variation data, i.e., the colorimetric fingerprint patterns, are analyzed by linear discriminant analysis, realizing the identification of the seven active substances with 100% accuracy. This work provides insights into the rational design of dual-atom catalysts with nanozyme activities for the discrimination of multiple targets.