Self-assembly vertically cross-linked 3D Bi3Ti2O8F nanosheets for colorimetric and electrochemical mimic peroxidase sensor

Hydrogen peroxide (H 2 O 2 ) is an important messenger molecule in vivo. The next generation sensor demands for intelligence and integration. Three-dimensional nanosheet structure is of considerable interest for the development of highly stable and sensitive sensor. This paper describes the synthesis of self-assembly vertically cross-linked 3D Bi 3 Ti 2 O 8 F nanosheets/Au (3D-BTOF Ns/Au) electrode. And its application as a high effective H 2 O 2 sensor was explored. The combination of colorimetric and electrochemical sensing, plays a synergistic role in the qualitative and quantitative detection of H 2 O 2 . Colorimetric sensing was applied to identify the existence or not of H 2 O 2 . Amperometric measurements were further performed to quantitatively detect H 2 O 2 . The 3D-BTOF Ns/Au sensor showed an outstanding sensitivity of 1764   μA   mM −   1   cm −   2 , response time of 2   s and low detecting limit of 1.43   μM. The unique vertically cross-linked structure provides abundant electroactive sites for adherence of H 2 O 2 . Particularly, the layered intergrowth structure of [F–Bi–O–Bi–F] sheets can induce an internal electric field (IEF), which greatly benefits to the separation of electron-hole pairs. Appling the traditional Ti/Bi-based materials into the emerging sensing field is a successful attempt. The constructed 3D-BTOF Ns/Au electrode holds promise as “a health guardian” for a real-time sensor to detect H 2 O 2 .