Study on catalytic efficiency of platinum and silver nanoparticles confined in nanosized channels of a 3-D mesostructured silica

Abstract

A scalable route to encapsulate homogeneously fine Pt and Ag nanoparticles (NPs) inside amine-functionalized KIT-6 mesochannels via two different reduction routes as heterogeneous mesoporous catalysts is demonstrated. The active amine groups functionalized KIT-6 mesochannels act as anchor sites to immobilize the homogeneous Pt and Ag NPs catalysts with small-sized NPs of approximately 6.0 and 3.0 nm, respectively. The catalysts were fully characterized, and the surface areas were relatively decreased after deposition of the metals NPs. Even after metal NPs deposition, the mesochannels are readily accessible for enhancing their catalytic activity. The meso-KIT-6-Pt catalyst synthesized with ascorbic acid (AA) reduction route shows a higher catalytic efficiency for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with a reaction rate almost 2 times higher than that of the meso-KIT-6-Ag synthesized using formaldehyde. The as-prepared mesoporous catalysts exhibit a good reusability, with a high catalytic efficiency for at least 5 successive cycles without an obvious loss in their catalytic activity. The influences of reaction parameters, such as catalyst dose, reaction temperarture and nature of solvent on the catalytic performance of the mesoporous catalysts are of the main study.