Ultrafine V2O5-anchored 3D N-doped carbon nanocomposite with augmented dual-enzyme mimetic activity for evaluating total antioxidant capacity

• Published in: Analytica chimica acta 2023-04, Vol.1252, p.341072-341072, Article 341072
• Main Authors: Wang, Qi, Ding, Yongli, Dahlgren, Randy A., Sun, Yue, Gu, Jingjing, Li, Yuhao, Liu, Tingting, Wang, Xuedong
• Format: Article
• Language: English
• Subjects: 3D-V2O5/NC nanocomposite; Dual-enzyme mimetic activity; Smartphone-based colorimetric sensor; Superoxide anion; Total antioxidant capacity; Vanadium pentoxide
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2023.341072

Total antioxidant capacity (TAC) can be evaluated by detecting the content of antioxidants, such as ascorbic acid, based on the enzyme-mimetic activity of nanomaterials. Herein, we fabricated a 3D-V2O5/NC nanocomposite using a self-templating strategy, which achieved ultrafine particles (∼2.5 nm), a porous carbon layer, large specific surface area (152.4 m2/g), N-doping and heterogeneous structure. The strong catalytic activity of 3D-V2O5/NC resulted from the integrated effect between the ultrafine structure of V2O5 nanoparticles and the 3D porous nitrogen-doped carbon framework, effectively increasing the number of active sites. This nanozyme presented a higher catalytic activity than its components or precursors in the nanocomposite (e.g., VN/NC, NC, V2O5, and VO2/g-C3N4). ROS scavenging experiments confirmed that the dual enzyme-like activity of 3D-V2O5/NC (catalase-like and oxidase-like) resulted from their co-participation of ‧O2−, h+ and ‧OH, among which ‧O2− played a crucial role in the catalytic color reaction. By virtue of the 3D-V2O5/NC nanoenzyme activity and TMB as a chromogenic substrate, the mixed system of 3D-V2O5/NC + TMB + H2O2 provided a low detection limit (0.03 μM) and suitable recovery (93.0–109.5%) for AA. Additionally, a smartphone-based colorimetric application was developed employing "Thing Identify" software to evaluate TAC in beverages. The colorimetric sensor and smartphone-detection platform provide a better or comparable analytical performance for TAC assessment in comparison to commercial ABTS test kits. The newly developed smartphone-based colorimetric platform presents several prominent advantageous, such as low cost, simple/rapid operation, and feasibility for outdoor use. [Display omitted] •A 3D-V2O5/NC nanocomposite is fabricated by a self-templating strategy.•3D-V2O5/NC has dual enzyme-mimetic activity (oxidase-like and catalase-like).•Synergistic effect between N-doped carbon lamellae and multivalent V2O5 nanoparticles.•This method provides a low detection limit and suitable recovery for TAC.•Developed a smartphone-based colorimetric application (APP).