Iridium ultrasmall nanoparticles, worm-like chain nanowires, and porous nanodendrites: One-pot solvothermal synthesis and catalytic CO oxidation activity

被引:22
作者
Zhang, Tao [1 ]
Li, Shuai-Chen [1 ]
Zhu, Wei [1 ]
Ke, Jun [1 ]
Yu, Jing-Wen [1 ]
Zhang, Zhi-Ping [1 ]
Dai, Lin-Xiu [1 ]
Gu, Jun [1 ]
Zhang, Ya-Wen [1 ]
机构
[1] Peking Univ, Beijing Natl Lab Mol Sci, State Key Lab Rare Earth Mat Chem & Applicat,Coll, PKU HKU Joint Lab Rare Earth Mat & Bioinorgan Che, Beijing 100871, Peoples R China
关键词
Iridium nanocatalysts; Solvothermal synthesis; Size and shape control; CO oxidation activity; Annealing effect; CARBON-MONOXIDE; FACILE SYNTHESIS; CAPPING AGENTS; SURFACE-ENERGY; IONIC LIQUIDS; KINETICS; NANOCRYSTALS; METALS; IR; NANOSTRUCTURES;
D O I
10.1016/j.susc.2015.10.007
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We report a facile one-pot solvothermal synthesis of monodisperse iridium (Ir) ultrasmall (1.5-2.5 nm in diameter) nanoparticles (NPs), worm-like chain nanowires (NWs), and porous nanodendrites (NDs), for which CO oxidation reaction has been employed as a probe reaction to investigate the effects of nanoparticle size and surface-capping organics on the catalytic activities. Time-dependent experiments revealed that an oriented attachment mechanism induced by the strong adsorption of halide anions (Br- and I-) on specific facet of Ir nanoclusters or by decreasing the reduction rate of Ir precursors with changing their concentrations during the synthesis was responsible for the formation of Ir NWs and NDs. Annealing tests indicated that an O-2-H-2 atmosphere treatment turned out to be an effective measure to clean up the surface-capping organics of Ir NPs supported on commercial SiO2. Catalytic CO oxidation reaction illustrated that a significant improvement in the catalytic activity of CO oxidation reaction was achieved together with the changing of activation energies after such atmosphere treatment for the supported catalysts of the ultrasmall Ir NPs. It is noteworthy that this enhancement in catalytic activity could be ascribed to the changes in the surface status (including populations of Ir species in metallic and oxidized states, removal of surface capping organics, the variety of active sites, and total effective active site number) for the supported nanocatalysts during the atmosphere treatment. (C) 2015 Elsevier B.V. All rights reserved.
引用
收藏
页码:319 / 327
页数:9
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