1 research outputs found
Ultrafast Ambient-Air Exsolution on Metal Oxide via Momentary Photothermal Effect
The process of exsolution for the synthesis of strongly
anchored
metal nanoparticles (NPs) on host oxide lattices has been proposed
as a promising strategy for designing robust catalyst-support composite
systems. However, because conventional exsolution processes occur
in harsh reducing environments at high temperatures for long periods
of time, the choice of support materials and dopant metals are limited
to those with inherently high thermal and chemical stability. Herein,
we report the exsolution of a series of noble metal catalysts (Pt,
Rh, and Ir) from metal oxide nanofibers (WO3 NFs) supports
in an entirely ambient environment induced by intense pulsed light
(IPL)-derived momentary photothermal treatment (>1000 °C).
Since
the exsolution process spans an extremely short period of time (<20
ms), unwanted structural artifacts such as decreased surface area
and phase transition of the support materials are effectively suppressed.
At the same time, exsolved NPs (<5 nm) with uniform size distributions
could successfully be formed. To prove the practical utility of exsolved
catalytic NPs functionalized on WO3 NFs, the chemiresistive
gas sensing characteristics of exsolved Pt-decorated WO3 NFs were analyzed, exhibiting high durability (>200 cyclic exposures),
enhanced response (Rair/Rgas > 800 @ 1 ppm/350 °C), and selectivity toward
H2S target gas. Altogether, we successfully demonstrated
that ultrafast exsolution within a few milliseconds could be induced
in ambient conditions using the IPL-derived momentary photothermal
treatment and contributed to expanding the practical viability of
the exsolution-based synthetic approaches for the production of highly
stable catalyst systems