Hollow MnCo2O4 nanofibers as efficient oxidase mimics for sensitive detection of sulfite and l-cysteine have been developed.

Doping with transition metal ions has been regarded as one of the most effective means to optimize the catalytic efficiency of metal oxides. In this work, a general approach for the fabrication of Mo 6+ -doped Co 3 O 4 (Mo− Co 3 O 4 ) nanotubes for peroxidase mimicking has been demonstrated via an electrospinning method combined with a calcination process. The prepared Mo−Co 3 O 4 nanotubes exhibited a higher peroxidase-like catalytic activity than pure Co 3 O 4 nanotubes, and the highest catalytic activity is achieved when the molar fraction of Mo is 2.0%. The catalytic kinetic of Mo−Co 3 O 4 nanotubes follows a typical Michaelis−Menten mechanism, representing a strong affinity to H 2 O 2 and 3,3′,5,5′-tetramethylbenzidine (TMB) substrates. Because of the high catalytic efficiency of the Mo−Co 3 O 4 nanotubes, we have developed a facile and efficient strategy for the sensitive colorimetric determination of Lcysteine with a low detection limit of 24.2 nM. This detection limit is superior to many previous reported enzyme-like detection systems. Furthermore, a favorable selectivity toward the determination of Lcysteine based on this approach is also achieved, showing bright prospects in environmental monitoring and biomedical analysis.

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