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  • In situ growth of catalytic active Au-Pt bimetallic nanorods in thermoresponsive core-shell microgels.

In situ growth of catalytic active Au-Pt bimetallic nanorods in thermoresponsive core-shell microgels.

ACS nano (2010-11-19)
Yan Lu, Jiayin Yuan, Frank Polzer, Markus Drechsler, Johannes Preussner
ABSTRACT

Here, we demonstrate that bimetallic Au-Pt nanorods (NRs) can be grown in situ into thermosensitive core-shell microgel particles by a novel two-step approach. In the first step, Au NRs with an average width of 6.6 ± 0.3 nm and length of 34.5 ± 5.2 nm (aspect ratio 5.2 ± 0.6) were homogeneously embedded into the shell of PNIPA networks. The volume transition of the microgel network leads to a strong red shift of the longitudinal plasmon band of the Au NRs. In the second step, platinum was preferentially deposited onto the tips of Au NRs to form dumbbell-shaped bimetallic nanoparticles. The novel synthesis forms bimetallic Au-Pt NRs immobilized in microgels without impeding their colloidal stability. Quantitative analysis of the catalytic activity for the reduction of 4-nitrophenol indicates that bimetallic Au-Pt NRs show highly enhanced catalytic activity, which is due to the synergistic effect of bimetallic nanoparticles. The catalytic activity of immobilized Au-Pt NRs can be modulated by the volume transition of thermosensitive microgels. This demonstrates that core-shell microgels are capable of serving as "smart nanoreactors" for the catalytic active bimetallic nanoparticles with controlled morphology and high colloidal stability.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
N,N′-Methylenebis(acrylamide), 99%
Sigma-Aldrich
N,N′-Methylenebisacrylamide, suitable for electrophoresis (after filtration or allowing insolubles to settle)
Sigma-Aldrich
N,N′-Methylenebisacrylamide, powder, for molecular biology, suitable for electrophoresis, ≥99.5%
Sigma-Aldrich
N,N′-Methylenebis(acrylamide), ≥99.0%
Sigma-Aldrich
N,N′-Methylenebisacrylamide solution, suitable for electrophoresis, 2% in H2O