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.

Constructing Ni–Pt Bimetallic Catalysts for Catalytic Hydrogenation and Rearrangement of Furfural into Cyclopentanone with Insight in H/D Exchange by D2O Labeling

“… 32 , 33 Thus, the formation of Ni 0 after reduction by H 2 is confirmed. The d-spacing ( Figure 5 g) of Pt/Al 2 O 3 with the diffraction pattern ( Figure 5 h) indicates the (111) lattice plane of metallic Pt with a spacing of 0.233–0.237 nm, 34 − 36 indicating the formation of Pt 0 after H 2 reduction.…”

“…Additionally, d-spacing (Figure c,k) with the diffraction patterns (Figure d,l) of Ni-containing catalysts was obtained via HR-TEM, which indicates the (111) lattice plane of metallic Ni particles with a spacing of 0.201–0.210 nm. , Thus, the formation of Ni 0 after reduction by H 2 is confirmed. The d-spacing (Figure g) of Pt/Al 2 O 3 with the diffraction pattern (Figure h) indicates the (111) lattice plane of metallic Pt with a spacing of 0.233–0.237 nm, − indicating the formation of Pt 0 after H 2 reduction.…”

Cytocompatibility, Antimicrobial and Antioxidant Activity of a Mucoadhesive Biopolymeric Hydrogel Embedding Selenium Nanoparticles Phytosynthesized by Sea Buckthorn Leaf Extract

“…The crystallite size distribution, automatically determined by the PDXL software with the Scherrer equation, is presented at the bottom of Figure 1 c and it evidenced four populations of crystallites with crystallite sizes as multiples of about 3 nm, respectively, 3.5 nm, 6.7 nm, 8.9 nm and 12.3 nm, suggesting that the SeNPs’ grains are built as clusters of 3 nm crystallites. The SAXS diffractograms presented in Figure 1 d were performed at three different angle ranges and showed different small-angle diffraction peaks between 0.164° and 0.956° convoluted in a signal similar to other types of nanoparticles [ 34 ], whereas the polydispersity of nanoparticles with diameters between 6 and 100 nm is presented in Figure 1 e, with two main populations centered around 17 nm and 24 nm and two secondary populations centered around 10 nm and 50 nm. The SAXS particle sizes appear to also be multiples of about 3 nm, respectively, around 9 nm, 12 nm, 18 nm, 24 nm, 27 nm and 54 nm, suggesting that, similar to WAXS, the SeNPs nanograins are formed by clusters of 3 nm crystallites.…”