A novel triple enzyme-like activities nanozyme-based dual-mode colorimetric sensor detection for hydroquinone

Novel layered cubic MnCo 2 O 4 nanozyme was prepared by the hydrothermal method. • Layered cubic MnCo 2 O 4 has CAT, OXD and POD nanozyme activities. • Catalytic performance, mechanism and kinetics of MnCo 2 O 4 were systematically studied. • A sensitive colorimetric sensor based on MnCo 2 O 4 oxidase-like activity targets hydroquinone detection. • Smartphone-integrated portable dual-mode strategy is developed for on-site hydroquinone detection. Through a feasible hydrothermal method, a novel bimetallic oxide stratiform cube-like MnCo 2 O 4 nano-enzyme composite was synthesized. Notably, the redox couples of both Co 2+ /Co 3+ and Mn 2+ /Mn 3+ provided richer oxidation-reduction reactions, thereby leading to an enhanced catalytic activity. Significantly, MnCo 2 O 4 as an enzyme mimic with triple enzyme-like activities (catalase-like (CAT), peroxidase-like (POD), and oxidase-like (OXD)) could oxidize colorless 3,3′,5,5’-Tetramethylbenzidine (TMB) to blue oxTMB without the exogenous addition of H 2 O 2 . The catalytic performance, mechanism and kinetics of catalytic reaction were systematically investigated. Owing to the high oxidase activity of MnCo 2 O 4 , a sensitive chromogenic sensing platform for the quantitative detecting of hydroquinone (HQ) concentration was constructed. The colorimetric detection method showed excellent linear relationship (1.0 μM–100 μM), a short detection time (5 min), a low limit of detection (0.36 μM) and the recovery rate of 96.70%–99.28%, which reveals the potential of MnCo 2 O 4 nanozymes in biosensing and biocatalytic fields. Furthermore, a smartphone-based portable colorimetric analysis method was also developed. Download: Download high-res image (128KB) Download: Download full-size image