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Synthesis of PtAu Alloy Nanocrystals in Micelle Nanoreactors Enabled by Flash Heating and Cooling
Author(s) -
Zhang Dongtang,
Chen Chunnian,
Wang Xiayan,
Guo Guangsheng,
Sun Yugang
Publication year - 2018
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201700413
Subject(s) - micelle , nanoreactor , alloy , materials science , nanocrystal , chemical engineering , cyclohexane , microemulsion , bimetallic strip , metal , nanoparticle , nanotechnology , chemistry , organic chemistry , metallurgy , pulmonary surfactant , aqueous solution , engineering
A microwave‐assisted flash heating and cooling strategy has been developed for the rapid synthesis of bimetallic alloy nanocrystals made of immiscible metals in microemulsion micelle nanoreactors. The promising oxygen reduction reaction (ORR) catalysts of PtAu alloy nanocrystals with tunable compositions have been successfully synthesized by using the new strategy. The water‐in‐oil (w/o) microemulsion micelles contain strong microwave‐absorbing species (including metal ion precursors, reducing reagent, water, n‐butanol) and they are surrounded with cyclohexane that barely absorbs microwave. The selective absorption of microwave energy in the micelles enables the rapid production of well‐mixed PtAu alloy melt at extremely high local temperatures while the micelle walls are cooled with the cold pool of cyclohexane to freeze the PtAu alloy melt into PtAu alloy nanocrystals with a uniform distribution of metal atoms. Such flash heating inside micelle containers followed by the flash cooling on the micelle walls results in a non‐equilibrium thermodynamic condition to benefit the formation of alloy nanocrystals composed of two immiscible metals.