Dual-interface combination of bowknot-like LaSe/FeSe/C heterostructure with abundant active sites for high-efficiency electrochemical detection of carbamate pesticides.

Electrochemical biosensing has great potential as sensitive assays to monitor carbamate pesticides for safeguarding human health and preserving the ecosystem. However, the rational design of electrode materials with high electrochemical activity and stability remains a tough challenge. The interfacial electric field (IEF) in heterojunction can facilitate efficient electron transfer kinetics, thereby heightening the sensitivity of biosensing devices. Herein, the challenge is addressed by exploiting a dual-interface design strategy, and bowknot-like LaSe/FeSe/C heterostructure was elegantly synthesized as electrode material, exhibiting ascendant electrochemical activity and structural stability. Additionally, the LaSe/FeSe/C material provides numerous active sites as well as heterogeneous interface, which synergistically promote accelerated charge transfer kinetics and enzyme-catalyzed reactions. Remarkably, the sensing platform exhibits an extremely low Michaelis constant (K, 43 μM), indicating superior substrate affinity that directly boosts the sensitivity of electrochemical biosensor. Furthermore, the constructed biosensing platform achieved wide linear response ranges (2.6 × 10-2.6 × 10 M, 4.2 × 10-4.2 × 10 M), ultralow detection limits (LOD = 4.90 × 10 M and 1.04 × 10 M) for aldicarb sulfone and carbofuran, respectively. Additionally, the good recoveries (91.6 % ∼ 106.4 %) and low relative standard deviation (RSD) for aldicarb sulfone and carbofuran assay in cucumber and apple samples demonstrated application potential of the designed LaSe/FeSe/C heterostructure in various electrochemical sensing systems.