Size-Controlled Pd Nanoparticle Catalysts Prepared by Galvanic Displacement into a Porous Si-Iron Oxide Nanoparticle Host

Abstract

Porous silicon nanoparticles containing both Pd and iron oxide nanoparticles are prepared and studied as magnetically recoverable catalysts for organic reductions. The Pd nanoparticles are generated in situ by electroless deposition of Pd(NH), where the porous Si skeleton acts as both a template and as a reducing agent and the released ammonia ligands raise the local pH to exert control over the size of the Pd nanoparticles. The nanocomposites are characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, nitrogen adsorption, X-ray diffraction, superconducting quantum interference device magnetization, and dynamic light scattering. The nanocomposite consists of a porous Si nanoparticle (150 nm mean diameter) containing ∼20 nm pores, uniformly decorated with a high loading of surfactant-free Pd nanoparticles (12 nm mean diameter) and superparamagnetic γ-FeO nanoparticles (∼7 nm mean diameter). The reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride is catalyzed by the nanocomposite, which is stable through the course of the reaction. Catalytic reduction of the organic dyes methylene blue and rhodamine B is also demonstrated. The conversion efficiency and catalytic activity are found to be superior to a commercial Pd/C catalyst compared under comparable reaction conditions. The composite catalyst can be recovered from the reaction mixture by applying an external magnetic field due to the existence of the superparamagnetic iron oxide nanoparticles in the construct. The recovered particles retain their catalytic activity.

Facile Fabrication of Highly Dispersed Pd@Ag Core–Shell Nanoparticles Embedded in Spirulina platensis by Electroless Deposition and Their Catalytic Properties

“…And the turnover frequency, defined as moles of 4‐NP reduced per mole of Ag per unit time, was calculated to be 2893 h −1 for the reduction of 4‐NP. This quantified activity parameters are superior to previously reported results of related template‐based metallic catalyst used in 4‐NP reduction reactions: MpSi‐Pd catalyst (TOF: 85.1 h −1 ), nano‐Au fixed on glass fibers (TOF: 324 h −1 ), Ag@FDU‐15 nanocomposites (TOF: 444 h −1 ), Pd–ZnO hybrid nanocatalyst (TOF: 518.4 h −1 ), AuNPs/AOBC nanohybrids (TOF: 1190 h −1 ), and Ag(0.3)@SBA‐15‐(10) nanocatalyst (TOF: 1210 h −1 ) . More literature and information are listed in Table S3 (Supporting Information).…”

Poly(amic acid) salt‐mediated palladium and platinum nanoparticles as highly active and recyclable catalysts for hydrogenation of nitroarenes in water under ambient conditions

“…As shown in Table 1, the activity parameters of as-prepared PdNPs-PAAS and PtNPs-PAAS catalysts are much higher than that of the other reported Pd-and Pt-based heterogeneous catalysts. [29][30][31][32][33][34][35][36][37] It is well known that the induction phenomenon is typical of heterogeneous catalytic reactions and commonly related to diffusion-controlled adsorption of reactants onto the metal surface, and metal surface activation or restructuring. [28] However, it is noticeable that no obvious induction period was observed in our catalytic systems, which probably benefited from the fast mass-transfer rate of reactants and the high accessibility of NPs surface in the quasi-homogeneous PAAS medium.…”

“…Next, the activity and the scope of the PtNPs-PAAS catalyst in the hydrogenation of nitroarenes were also PDDA-PdNPs 0.12 3.5 2300 5 5.7 × 10 −2 24.8 [29] PDDA-PtNPs 0.12 3.5 1250 6 3 × 10 −2 24 [29] PtNPs-mycelia 0.1 10 1070 3.3 1.2 × 10 −3 11.25 [30] MpSi-PdNPs 1 100 23.6 12 1.55 × 10 −3 66 [31] PtNPs-PDA/RGO 0. Table 3.…”

Shape Control of Monodispersed Sub‐5 nm Pd Tetrahedrons and Laciniate Pd Nanourchins by Maneuvering the Dispersed State of Additives for Boosting ORR Performance

“…When using C 20 H 14 (1,1′-binaphthalene) + 2NH 3 as additives, the strong adsorption and relative fast reduction rate may force the growth into thermodynamics controlled products with low specific surface energy, thus achieving the monodispersed sub-5 nm Pd tetrahedrons with high conversion and morphology yields (purity > 98%). [26][27][28][29] As soon as adding C 20 H 14 +2NH 3 ·H 2 O into PdCl 4 2− solution, the solution color immediately changed from dark orange to colorless. The resultant sub-5 nm Pd tetrahedrons and Pd LUs were found to be excellent electrocatalysts in both ORR and formic acid oxidation reaction (FAOR), outperforming most of the state-of-the-art Pd catalysts.…”