Fabrication of oxidase-like hollow MnCo2O4 nanofibers and their sensitive colorimetric detection of sulfite and L-cysteine

Mixed transition-metal oxides (MTMOs) have attracted much research interest because of their promising applications in artificial enzymes. In this work, uniform hollow MnCo2O4 nanofibers have been fabricated via an electrospinning technique followed by a calcination process, which can be used as efficient oxidase mimics. In detail, the as-prepared hollow MnCo2O4 nanofibers display excellent oxidase-like activity toward the oxidation of 3,3', 5,5'-tetramethylbenzidine (TMB) superior to their corresponding single-metal oxides without the addition of H2O2. Based on the high catalytic activity of hollow MnCo2O4 nanofibers and their inhibition effect by specific substances, the system of hollow MnCo2O4 nanofibers-TMB has potential to be applied in assays to detect sulfite and L-cysteine using a colorimetric approach with high sensitivity and selectivity. This work implies a broad application prospect of MTMOs in bio-sensors, environmental protection, food safety and medical science.