High-performance electrochemical biosensor for nonenzymatic H2O2 sensing based on Au@C-Co3O4 heterostructures.

An ingenious and viable method for preparing heterogeneous Co3O4 dodecahedrons that contain carbon and encapsulated Au nanoparticles (Au@C-Co3O4) was proposed via pyrolysis of Au nanoparticle-encapsulated zeolitic imidazolate framework-67 (Au@ZIF-67). The obtained Au@C-Co3O4 possessed hierarchically porous structure, abundant active sites, excellent conductivity, and durability, all of which can significantly improve the analysis performance of the biosensor. Meanwhile, the fabricated electrode based on the porous Au@C-Co3O4 showed remarkable electrocatalytic performance towards H2O2 with a limit of detection of 19 nM and ultra-high sensitivity of 7553 μA mM-1 cm-2, even when the Au content in the composite was as low as 0.85 wt%. This novel biosensor was successfully used to monitor H2O2 concentration released from living cells, and the results can be used to identify cancer cells, thus advancing the use of transition metal oxides in the field of biosensing.