title: Highly dispersed CeO₂ on TiO₂ nanotube: a synergistic nanocomposite with superior peroxidase-like activity.
abstract: In this report, a novel nanocomposite of highly dispersed CeO2 on a TiO2 nanotube was designed and proposed as a peroxidase-like mimic. The best peroxidase-like activity was obtained for the CeO2/nanotube-TiO2 when the molar ratio of Ce/Ti was 0.1, which was much higher than that for CeO2/nanowire-TiO2, CeO2/nanorod-TiO2, or CeO2/nanoparticle-TiO2 with a similar molar ratio of Ce/Ti. Moreover, in comparison with other nanomaterial based peroxidase mimics, CeO2/nanotube-TiO2 nanocomposites exhibited higher affinity to H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB). Kinetic analysis indicated that the catalytic behavior was in accordance with typical Michaelis-Menten kinetics. Ce(3+) sites were confirmed as the catalytic active sites for the catalytic reaction. The first interaction of surface CeO2 with H2O2 chemically changed the surface state of CeO2 by transforming Ce(3+) sites into surface peroxide species causing adsorbed TMB oxidation. Compared with CeO2/nanowire-TiO2, CeO2/nanorod-TiO2, and CeO2/nanoparticle-TiO2, the combination of TiO2 nanotube with CeO2 presented the highest concentration of Ce(3+) thus leading to the best peroxidase-like activity. On the basis of the high activity of CeO2/nanotube-TiO2, the reaction provides a simple method for colorimetric detection of H2O2 and glucose with the detection limits of 3.2 and 6.1 μM, respectively.
authors.affiliation: Key Laboratory of Food Colloids and Biotechnology (Ministry of Education of China), School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Food Colloids and Biotechnology (Ministry of Education of China), School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China.
authors.forename: Yuming
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Key Laboratory of Food Colloids and Biotechnology (Ministry of Education of China), School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China.
authors.forename: Pingping
authors.initials: P
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Food Colloids and Biotechnology (Ministry of Education of China), School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China.
authors.forename: Guangli
authors.initials: G
authors.lastname: Wang
authors.affiliation: Key Laboratory of Food Colloids and Biotechnology (Ministry of Education of China), School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Zhang
mesh_terms: D001560:Benzidines / Q000737:chemistry; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007700:Kinetics; D053761:Nanocomposites / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D009195:Peroxidase / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D001560:Benzidines; C009495:titanium dioxide; D002563:Cerium; C021758:3,3',5,5'-tetramethylbenzidine; C030583:ceric oxide; D006861:Hydrogen Peroxide; D014025:Titanium; D009195:Peroxidase
keywords: CeO2/TiO2 nanocomposite; H2O2; glucose; peroxidase mimic; synergistic effect