Encapsulating Metal Nanoparticles into a Layered Zeolite Precursor with Surface Silanol Nests Enhances Sintering Resistance**

Abstract

Supported metal nanoparticles are used as heterogeneous catalysts but often deactivated due to sintering at high temperatures. Confining metal species into a porous matrix reduces sintering, yet supports rarely provide additional stabilization. Here, we used the silanol‐rich layered zeolite IPC‐1P to stabilize ultra‐small Rh nanoparticles. By adjusting the IPC‐1P interlayer space through swelling, we prepared various architectures, including microporous and disordered mesoporous. In situ scanning transmission electron microscopy confirmed that Rh nanoparticles are resistant to sintering at high temperature (750 °C, 6 hrs). Rh clusters strongly bind to surface silanol quadruplets at IPC‐1P layers by hydrogen transfer to clusters, while high silanol density hinders their migration based on density functional theory calculations. Ultimately, combining swelling with long‐chain surfactant and utilizing metal‐silanol interactions resulted in a novel, catalytically active material—Rh@IPC_C22.

Effect of Intracrystalline Silanol Defects on the Diffusivity of Benzene in Silicalite Zeolite

“…A similar result was obtained by Qin and co-workers, where the existence of silanol defects was responsible for the fast deactivation of the catalyst during methanol to hydrocarbon transformation [20]. Li et al [21] used silanol-rich IPC-1P zeolite as support for rhodium nanoparticles and found out that silanol nests stabilize Rh particles due to hydrogen transfer between rhodium particles and silanols. As evidenced from these studies along with many others [22][23][24][25][26], the role of silanol groups on the catalytic performance of zeolites have been widely explored.…”

Pd Nanoparticles on the Outer Surface of Microporous Aluminosilicates for the Direct Alkylation of Benzenes using Alkanes

“…Since the pore diameter of ZSM-5 zeolite is only 0.55 nm, the images indicate the presence of Pd nanoparticles (diameter: 5–6 nm) on the outer surface of H-ZSM-5. The Pd nanoparticles are possibly stabilized by surface silanols . High-resolution TEM (HRTEM) images of Pd nanoparticles in the recovered catalyst were also measured and analyzed, where periodic lattice fringes could be resolved (Figure S3 in the Supporting Information).…”

“…The Pd nanoparticles are possibly stabilized by surface silanols. 40 High-resolution TEM (HRTEM) images of Pd nanoparticles in the recovered catalyst were also measured and analyzed, where periodic lattice fringes could be resolved (Figure S3 in the Supporting Information). The interplanar spacing of 0.22 nm corresponds to the {111} plane of metallic Pd with a face-centered cubic (fcc) structure.…”

Tin Active Sites Confined in Zeolite Framework as a Promising Shape‐Selective Catalyst for Ethylene Oxide Hydration

“…[28,29] Different from the direct hydrothermal crystallization of zeolite, the ADOR process allow the manipulation of zeolites with predicted structure, continuously tunable porosity and various catalytic active sites. [17,[28][29][30][31][32][33] Herein, we post-synthesized a new stannosilicate with the PCR structure, a derivative zeolite topology developed by ADOR strategy. Through systematic removal of the double four ring (d4r) units of germanosilicate UTL in acidic aqueous solution and subsequent solid-liquid isomorphous incorporation of tetrahedral Sn ions, Sn-PCR was prepared (Scheme 1).…”