Engineering porous Co-Mn oxide nanosheets with abundant oxygen vacancy as an efficient oxidase-like mimic for heparin colorimetric sensing

Defects engineering as an effective strategy was widely utilized to modulate catalytic performance for heterogeneous catalysts through tuning surface electronic surface and creating more active sites. In this work, porous Co-Mn oxide nanosheets with abundant oxygen vacancies (OVs-CMO NSs) were prepared via a simple one-stone-two-birds method. OVs were verified by various characterizations and found more favorable for O-2 absorption and activation to produce more reactive O-2 center dot- radical, resulting in an improved oxidase-like activity in initiating 3,3',5,5'-tetramethylbenzidine (TMB) oxidation, with a lower K-m value of 0.00717 mM and a higher V-max of 2.086 x 10(-7) M/s. Since heparin (Hep) shows an inhibition effect on OVs-CMO NSs-TMB chromogenic system due to strong absorption, a colorimetric sensing platform for Hep detection was established. The present colorimetric detection shows high sensitivity, good selectivity and reliability for normal goat serum. This work not only provides a high-performance non-precious metal oxidase mimic prepared by simple surface defect engineering, but also builds a sensitive colorimetric method for Hep detection. (C) 2022 Published by Elsevier B.V.

Automated summary

Defects engineering was utilized to tune the catalytic performance of heterogeneous catalysts by modulating the surface electronic structure and creating more active sites. In this work, porous Co-Mn oxide nanosheets with abundant oxygen vacancies were prepared, and the oxygen vacancies were found to enhance O-2 absorption and activation, resulting in improved oxidase-like activity. A colorimetric sensing platform for heparin detection was established based on the inhibition effect of heparin on the oxidase-like activity of the nanosheets. This study provides a high-performance non-precious metal oxidase mimic and a sensitive colorimetric method for heparin detection.