Building caterpillar-like 3D hierarchical FeS2@C@SnS2 heterostructures endowing robust electrochemical activity for sensing trace level dopamine

Here a caterpillar-like three-dimensional (3D) FeS2@C@SnS2 hierarchical heterostructure with heteronuclear bimetallic active sites and protective/conductive carbon layer was well-engineered for enhancing the peroxidase-like behavior significantly. By in-situ growth of SnS2 nanosheets over MIL-88A@PDA derived FeS2@C, it achieves abundant spatially separated FeS2 and SnS2 reactive sites to perform their catalyzing action maximumly, and create heterophase interfaces between different building blocks to accelerate ion conduction/electron transport, while the existence of carbon layer can preserve the integrality of 3D configuration well and suppress the structural deformation when participating electrocatalytic reaction. As a sensing application, such a FeS2@C@SnS2 sensor delivers sufficient electrocatalytic locations, fast electronic kinetics, and structural robustness to capture selectively and measure efficiently DA molecule, and produce appealing electrochemical performance that are especially prominent for its high sensitivity (382.2 μA μM−1 cm−2) and ultra-low LOD (0.116 nM). Additionally, the powerful sensitivity and stability characteristics enable it to check DA in human serum efficiently and obtain satisfactory results. Undoubtedly, this work uncovers new insights for engineering heterostructure composites and further expanding their applications in complex biosystems.