Size-Controlled Growth of Silver Nanoparticles onto Functionalized Ordered Mesoporous Polymers for Efficient CO₂ Upgrading

Abstract

Highly dispersed metallic silver nanoparticles (AgNPs) are promising heterogeneous catalysts for carboxylative coupling of terminal alkynes with CO2 under mild conditions. Yet, their size-controlled synthesis is very challenging because of the high surface energy. Here, we prepared a series of amino-functionalized ordered mesoporous polymers as hosts for anchoring AgNPs. Control experiments and computations showed that electron-rich amines were confined in mesochannels with varying electron density and steric hindrance, creating “localized active zones (LAZ)” to control the growth of AgNPs. The particle size of AgNPs grows along with the increased volume of LAZ around nitrogen species. We also revealed that the catalytic activity of Ag-based catalysts is size-dependent and increases with decreasing particle size. Building on these findings, we report a facile one-pot synthesis strategy for preparing an amine-incorporated ordered mesoporous polymer (NOMP) with a high specific surface area, small LAZ volume, and uniform amine sites with controllable loading. These features result in the formation of ultrasmall and monodispersed Ag nanoparticles. Remarkably, Ag@NOMP gave a quantitative target yield under the conditions of 1 atm CO2 pressure and 50 °C, showing superior catalytic activity in CO2 carboxylation compared to other mesoporous analogues.

Confinement synthesis in porous molecule-based materials: a new opportunity for ultrafine nanostructures

“…9b). 114 The aminos can be coordinated with Ag + , and their different types determine the activity range of their coordination. They called the enriched electron zones near N the "localized active zones (LAZs)".…”

Recent advances in catalytic conversion of carbon dioxide to propiolic acids over coinage-metal-based catalysts

“…Theoretical calculation shows that the amide groups around silver NPs can effectively capture carbon dioxide, providing an ideal microenvironment for carbon dioxide immobilization and transformation. Furthermore, a variety of silver-based catalyst were developed, such as CTF-DCE-Ag, Ag@FeNT, CeO 2 -Ag, Ag@NOMP, Ag NPs@MCC, Ag/PCNF-700, Ag/MÀCeO 2 , which deliver a message that the size and dispersion of NPs are usually the main factors affecting the performance of catalysts [99][100][101][102][103][104][105].…”

Direct synthesis of triphenylamine-based ordered mesoporous polymers for metal-free photocatalytic aerobic oxidation

“…21 More importantly, the highly ordered mesoporous morphology would facilitate π-delocalization through enhanced charge carrier transport within the polymer, 13 a ,22 thus promoting OMPs as promising heterogeneous photocatalysts. In this regard, several groups have demonstrated the excellent performance of OMP-based catalysts in acid/base catalysis, 23 metal catalysis, 24 CO 2 conversions, 25 and biomass conversions. 26 Very recently, we have developed the rapid construction of a TEMPO-functionalized ordered mesoporous polymer via a pore surface engineering strategy, which was used as an active and reusable organocatalyst for several aerobic oxidative reactions.…”