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

Supported metal nanoparticles are widely used as heterogeneous catalysts but often deactivated due to sintering under harsh conditions, especially at high temperatures. Sintering can be prevented by confining metal species into a porous matrix, although supports rarely provide additional stabilization effects. Herein, we used silanol-rich layered zeolite, IPC-1P, to stabilize ultra-small Rh nanoparticles. By adjusting the interlayer space of the precursor through swelling, we prepared various architectures, including microporous Rh@IPC-4_C12 and disordered mesoporous Rh@IPC_C22. By in-situ scanning transmission electron microscopy, we confirmed that immobilized Rh nanoparticles are resistant to sintering at high temperatures (650 oC for 2hrs). Our density functional theory (DFT) calculations indicated that small Rh clusters strongly bind to the surface silanol quadruplets at IPC-1P layers through hydrogen transfer to the metallic particles, while high silanol density hinders migration on the surface. Ultimately, combining swelling with long-chain surfactant and utilizing metal-silanol interactions resulted in a novel, catalytically active zeolitic material termed Rh@IPC_C22.