Biotemplated fabrication of N/O co-doped porous carbon confined spinel NiFe2O4 heterostructured mimetics for triple-mode sensing of antioxidants and ameliorating packaging properties.

[Display omitted] • Magnetic N/O codoped porous carbon (MNPC) was prepared using shrimp shell. • MNPC had multi-enzyme activities, especially the excellent oxidase-like activity. • Catalytic activities of MNPC can be regulated by changing pyrolysis temperature. • MNPC can be successfully used for dual-signal triple-mode sensing antioxidants. • MNPC nanozyme can be innovatively used to improve the packaging properties. In this work, shrimp shell-derived magnetic NiFe 2 O 4 /N, O co-doped porous carbon nanozyme with superior oxidase (OXD)-like activity was prepared and used for colorimetric/photothermal/smartphone dual-signal triple-mode detection of antioxidants in fruits and beverages. The magnetic NiFe 2 O 4 /N, O co-doped porous carbon (MNPC) material was triumphantly fabricated using a combined in-situ surface chelation and pyrolysis method. The resultant MNPC composite exhibits a superior OXD-like activity, which can effectively oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) for yielding colorimetric/temperature dual-signal (CTDS) in absence of H 2 O 2. This CTDS output sensor was successfully used for the determination of ascorbic acid and tannic acid. The proposed CTDS sensor with good specificity and high sensitivity can satisfy different on-site analysis requirements. Interestingly, the MNPC as a sustainable filler was further used for improving packaging properties of polyvinyl alcohol film. In short, this work offers a large-scale and cheap method to fabricate magnetic carbon-based nanozyme for monitoring antioxidants and ameliorating packaging properties. [ABSTRACT FROM AUTHOR]