High-Temperature Pulse Method for Nanoparticle Redispersion

doi:10.1021/jacs.0c04887

High-Temperature Pulse Method for Nanoparticle Redispersion

2020-09-11

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DOI：10.1021/jacs.0c04887

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Nanoparticles suffer from aggregation and poisoning issues (e.g., oxidation) that severely hinder their long-term applications. However, current redispersion approaches, such as continuous heating in oxidizing and reducing environments, face challenges including grain growth effects induced by long heating times as well as complex procedures. Herein, we report a facile and efficient redispersion process that enables us to directly transform large aggregated particles into nanoscale materials. In this method, a piece of carbon nanofiber film was used as a heater and high treatment temperature (similar to 1500-2000 K) is rapidly elevated and maintained for a very short period of time (100 ms), followed by fast quenching back to room temperature at a cooling rate of 10(5) K/s to inhibit sintering. With these conditions we demonstrate the redispersion of large aggregated metal oxide particles into metallic nanoparticles just similar to 10 nm in size, uniformly distributed on the substrate. Furthermore, the metallic states of the nanoparticles are renewed during the heat treatment through reduction. The redispersion process removes impurities and poisoning elements, yet is able to maintain the integrity of the substrate because of the ultrashort heating pulse time. This method is also significantly faster (ca. milliseconds) compared to conventional redispersion treatments (ca. hours), providing a pragmatic strategy to redisperse degraded particles for a variety of applications.

Keywords:

PALLADIUM NANOPARTICLES

OXIDATION-REDUCTION

LEACHING MECHANISM

CATALYSTS

PARTICLES

EFFICIENT

SUPPORT

COBALT

High-Temperature Pulse Method for Nanoparticle Redispersion

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