Ultrasonication‐Induced Strong Metal‐Support Interaction Construction in Water Towards Enhanced Catalysis

Abstract

The development of facile methodologies to afford robust supported metal nanocatalysts under mild conditions is highly desirable yet challenging, particularly via strong metal-support interactions (SMSI) construction. State-of-the-art approaches capable of generating SMSI encapsulation mainly focus on high temperature annealing in reductive/oxidative atmosphere. Herein, ultra-stable metal nanocatalysts based on SMSI construction were produced by leveraging the instantaneous high-energy input from ultrasonication under ambient conditions in H 2 O, which could rapidly afford abundant active intermediates, Ti 3 + ions, and oxygen vacancies within the scaffolds to induce the SMSI overlayer formation. The encapsulation degree could be tuned and controlled via the reducibility of the solvents and the ultrasonication parameters. This facile and efficient approach could be further extended to diverse metal oxide supports and noble metal NPs leading to enhanced performance in hydrogenation reactions and CO 2 conversion.

Water-assisted generation of catalytic interface: The case of interfacial Pt-FeOx(OH)y sites active in preferential carbon monoxide oxidation

“…3,4,14,15 Strong metal-support interaction manifested as stabilization and encapsulation of metal nanoparticles on reducible oxidic supports can also be influenced by water. [16][17][18] In some cases, this metal-support interaction leads to the nanoparticles growth or to changes in the size distribution, as it was shown for Pt/CeO2. 19 At the same time, another study demonstrated that the blockage of surface oxygen vacancies on TiO2 by water hinders any restructuring of supported Pt nanoparticles even at 873 K. 20 The influence of water on the structure of metal-support interfaces therefore depends significantly on the nature of the system and is not properly studied.…”

“…Similar effects were observed for supported metal nanoparticles demostrating of strong metal-support interaction. 17,18,32 It should be mentioned that Pt-Fe alloying during reduction up to 473 K was excluded by EXAFS, as shown in Figure S11. 26 To check the influence of water on the PROX activity of these catalysts, we added water vapor directly to the reaction feed.…”

“…To further understand the promoting effect both of the water-assisted pretreatment and direct water addition into the feed, we performed targeted experiments with 18 O-labeled water. In these experiments, initially-calcined Pt2.1Fe3.6-Al2O3 was impregnated with H2 18 O instead of standard water and then exposed to the same reduction and reaction procedures as the original Pt2.1Fe3.6-Al2O3-wet-473-100 and Pt2.1Fe3.6-Al2O3-wet-373-100 catalysts.…”

“…To further understand the promoting effect both of the water-assisted pretreatment and direct water addition into the feed, we performed targeted experiments with 18 O-labeled water. In these experiments, initially-calcined Pt2.1Fe3.6-Al2O3 was impregnated with H2 18 O instead of standard water and then exposed to the same reduction and reaction procedures as the original Pt2.1Fe3.6-Al2O3-wet-473-100 and Pt2.1Fe3.6-Al2O3-wet-373-100 catalysts. Figure S7a shows no evidence of 18 O-labeled oxygen, carbon monoxide, carbon dioxide, or even water under the catalytic conditions over Pt2.1Fe3.6-Al2O3-wet(H2 18 O)-473-100 pretreated at 473 K. This behavior explains why Pt2.1Fe3.6-Al2O3-473-100 and Pt2.1Fe3.6-Al2O3-wet-473-100 demonstrate similar activities.…”

“…In these experiments, initially-calcined Pt2.1Fe3.6-Al2O3 was impregnated with H2 18 O instead of standard water and then exposed to the same reduction and reaction procedures as the original Pt2.1Fe3.6-Al2O3-wet-473-100 and Pt2.1Fe3.6-Al2O3-wet-373-100 catalysts. Figure S7a shows no evidence of 18 O-labeled oxygen, carbon monoxide, carbon dioxide, or even water under the catalytic conditions over Pt2.1Fe3.6-Al2O3-wet(H2 18 O)-473-100 pretreated at 473 K. This behavior explains why Pt2.1Fe3.6-Al2O3-473-100 and Pt2.1Fe3.6-Al2O3-wet-473-100 demonstrate similar activities. This suggests that during the reduction at 473 K, adsorbed water species evaporate and therefore show no influence on the catalytic activity.…”