Lateral layered heterostructure bimetallic selenides Bi2Se3-FeSe2 @C for ultra-sensitive electrochemical sensing platform

Selenides possess more electroactive unsaturated edge sites and superior redox activity, due to larger ionic radius together with low electronegativity of Se in comparation with sulfur and oxygen. However, mono-metallic selenides still suffer from the intrinsic limitations of low conductivity and electrochemical activity, which hinders their application in electrochemical sensor. Benefiting from the synergistic effects, bimetallic selenides exhibit relatively high electrical conductivity and electrochemical property. Moreover, heterostructure engineering is identified as an ingenious technology to endow materials with desired functions for developing high performance devices. Herein, a carbon-encapsulated bimetallic selenides (Bi2Se3-FeSe2 @C) composite with lateral layered heterostructure was synthesized and employed as electrode material for electrochemical biosensing. The formed few-layered Bi2Se3-FeSe2 @C lateral heterostructure with a large surface area possesses superb electrochemical properties and abundant immobilized sites toward acetylcholinesterase (AChE). The robust AChE-NF/Bi2Se3-FeSe2 @C/GCE biosensor exhibited promising monocrotophos detection performance along with high sensitivity, a wide linear range (10−5 ∼10 µg mL−1) and low limit of detection (1.51 ×10−13 M).