title: Formation of PdPt alloy nanodots on gold nanorods: tuning oxidase-like activities via composition.
abstract: The island growth mode of Pt was employed to guide the forma-tion of PdPt alloy nanodots on gold nanorods (Au@PdPt NRs). Well-defined alloy nanodots, with tunable Pd/Pt ratios from 0.2 to 5, distribute homogeneously on the surface of the Au NR. Formation of nanodots shell leads to the red-shift and broadening of the longitudinal surface plasmon resonance (LSPR) band of the Au NRs. The Au@PdPt alloy NRs exhibit catalytic activity toward oxidation of often-used chromogenic substrates by dissolved oxygen under mild conditions, suggesting a new type of oxidase mimics. Composition dependence catalytic activity is observed for the oxidation of ascorbic acid (AA) and 3,3',5,5'-tetramethylbenzidine (TMB) and for the reduction of p-nitrophenol. For AA and TMB, catalytic activity enhances quickly at lower Pd/Pt ratios and tends to saturate at higher Pd/Pt ratios. For p-nitrophenol reduction, catalytic activity shows a nice linear relationship with Pd/Pt ratio owing to much higher catalytic activity of Pd. In conclusion, proper alloying of Pd and Pt presents an effective route to tailor the catalytic activity. Interesting, alloy nanodots can also catalyze the oxidation of Fe (II) to Fe (III) by dissolved oxygen. Thus, based on the competitive oxidation of TMB and Fe (II), selective detection of the latter can be achieved.
authors.affiliation: CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology , Zhongguancun, Beiyitiao No. 11, Beijing, 100190, P. R. China.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
authors.forename: Xiaona
authors.initials: X
authors.lastname: Hu
authors.forename: Jianbo
authors.initials: J
authors.lastname: Liu
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Yin
authors.forename: Shuai
authors.initials: S
authors.lastname: Hou
authors.forename: Tao
authors.initials: T
authors.lastname: Wen
authors.forename: Weiwei
authors.initials: W
authors.lastname: He
authors.forename: Yinglu
authors.initials: Y
authors.lastname: Ji
authors.forename: Yuting
authors.initials: Y
authors.lastname: Guo
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Wu
mesh_terms: D000497:Alloys / Q000737:chemistry*; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism; D010165:Palladium / Q000737:chemistry; D010316:Particle Size; D010984:Platinum / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000497:Alloys; D010984:Platinum; D010165:Palladium; D006046:Gold; D010088:Oxidoreductases