Chemical Synthesis and Characterization of Pd/SiO2: The Effect of Chemical Reagent

Abstract

The size and shape distribution of metal nanoparticles (NPs) are important parameters that need to be tuned in order to achieve desired properties of materials for practical applications. In the current work, we present the synthesis of palladium NPs supported on silica by three different methods, applying reduction by sodium borohydride, hydrazine vapors, and polyethylene glycol (PEG). The synthesized materials were characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, surface area and porosity measurements, and thermogravimetric analysis. Similar nanoparticle sizes with narrow size distribution centered at 8 nm were obtained after reduction by sodium borohydride and hydrazine vapors, whereas the smallest particle size of about 4.8 nm was obtained after reduction by PEG. The effect of modification of the initial palladium chloride compound by ammonium hydroxide was found to lead to the formation of larger particles with average size of 15 nm and broader size distribution. In addition, the process of the reduction of palladium by PEG at different reduction stages was monitored by UV-Vis spectroscopy. CO-stripping voltammetry showed that reduction in hydrazine and in PEG allowed the preparation of Pd NPs with high electrochemically-active surface area. Such NPs are promising materials for electrocatalysis.

Solvothermal Preparation and Electrochemical Characterization of Cubic ZrO2 Nanoparticles/Highly Reduced Graphene (HRG) based Nanocomposites

“…However, studies on the changes in the electrochemical properties of ZrO 2 NPs after the inclusion of graphene are rarely reported. The size of the NPs and surface chemistry play important roles in defining the electrochemical properties of materials [25]. Particularly, the size of NPs is an important factor in defining their electronic and optical properties.…”

The Effect of Alcohol on Palladium Nanoparticles in i-Pd(OAc)2(TPPTS)2 for Aerobic Oxidation of Benzyl Alcohol

“…Palladium salts and their complexes with Pd oxidation state +2 can be reduced by different agents, such as sodium borohydride or hydrazine [22]. Alternatively, alcohols, which bare acidic protons, can also be used to reduce Pd(II) to Pd(0) via the alcohol's binding to the complex.…”

In Situ Time-Resolved Decomposition of β-Hydride Phase in Palladium Nanoparticles Coated with Metal-Organic Framework

“…Palladium is well-known for its ability for dissociative adsorption and storage of hydrogen [1]. The hydrogen storage capacity and kinetics of hydrogen adsorption and desorption are strongly affected by the particle's size and shape [2][3][4][5][6][7][8], which is an important parameter for catalytic applications [8][9][10][11][12][13][14]. Bulk palladium materials exhibit a sharp phase transition from αto β-hydride, resulting in a characteristic plateau in the pressure composition isotherm [1].…”