Peroxidase-Mimetic and Fenton-Like Activities of Molybdenum Oxide Quantum Dots

Molybdenum oxide nanomaterials have become a popular nanomaterial while its catalysis behavior especially the bio-catalysis property is little understood, even though molybdenum has been employed as a key cofactor in several important enzymes in biological system. On the basis of these, the Fenton and peroxidase-like property of molybdenum oxide quantum dots (MoO(x)QDs) with mixed valence state was carefully investigated using tetramethylbenzidine (TMB) and methyl orange (MO) as the substrates. The results showed that MoO(x)QDs not only serve as a Fenton reagent, degrading MO to colorless products, but also exhibit intrinsic peroxidase-mimetic activity, oxidizing TMB to the oxidized state oxTMB. The catalysis mechanism of MoO(x)QDs is that MoO(x)QDs can facilitate the decomposition of H(2)O(2)and a large amount of radicals was generated, leading to MO decomposing and TMB oxidizing subsequently. Inspired by the findings, a visible method was developed for sensitive and selective detection of H(2)O(2)and glucose, and the limit of detection for H(2)O(2)and glucose is 7.75 mu M and 8.95 mu M (3 sigma/K), respectively. Moreover, glucose content in human serum samples was successfully determined by the proposed visible method, and the results are consistent well with those obtained by handheld glucose meter, suggesting a high accuracy of the present method.