Phase transition and catalyst functionalization in metal oxide using ultra-fast photothermal treatment for superior chemiresistive sensors

Abstract

restricting the choice of support materials and ex-solutes elements to feature high thermal stability to avoid thermal degradation. Here, we report intense pulsed light-derived high temperature transient photothermal effect on tungsten oxide nanofibers support materials to induce ex-solution of a series of noble metal catalysts (Pt, Rh, and Ir) in ambient air. Since the ex-solution process ends up within an extremely short time (20 ms), the thermal degradation of the support materials could be effectively avoided. At the same time, ex-solute metals are successfully ex-solved to form uniform size distributed sub-10 nm NPs. To prove the practical utility of ex-solved catalytic NPs functionalized on WO$_3$ NFs after IPL treatment, we demonstrated outstanding gas sensing performances, i.e., excellent selectivity, and remarkable durability toward H$_2$S. Altogether, we successfully demonstrated the new class of ambient air ex-solution phenomenon using the IPL-induced optical transient annealing process to overcome the challenges of conventional ex-solution methods and to contribute to expanding the ex-solution field for various applications.

Ex-solution phenomenon has been proposed as a promising strategy for designing high performance catalysts with remarkable high durability since ex-solved metal nanoparticles (NPs) are strongly anchored on host oxide lattices. However, recent ex-solution studies suffer from critical limitations such as the synthesis process of harsh reduction conditions at high temperature to ex-solve metallic NPs