Porous Nanocrystalline Silicon Supported Bimetallic Pd-Au Catalysts: Preparation, Characterization, and Direct Hydrogen Peroxide Synthesis

Abstract

Bimetallic Pd-Au catalysts were prepared on the porous nanocrystalline silicon (PSi) for the first time. The catalysts were tested in the reaction of direct hydrogen peroxide synthesis and characterized by standard structural and chemical techniques. It was shown that the Pd-Au/PSi catalyst prepared from conventional H2[PdCl4] and H[AuCl4] precursors contains monometallic Pd and a range of different Pd-Au alloy nanoparticles over the oxidized PSi surface. The PdAu2/PSi catalyst prepared from the [Pd(NH3)4][AuCl4]2 double complex salt (DCS) single-source precursor predominantly contains bimetallic Pd-Au alloy nanoparticles. For both catalysts the surface of bimetallic nanoparticles is Pd-enriched and contains palladium in Pd0 and Pd2+ states. Among the catalysts studied, the PdAu2/PSi catalyst was the most active and selective in the direct H2O2 synthesis with H2O2 productivity of 0.5 mol gPd-1 h-1 at selectivity of 50% and H2O2 concentration of 0.023 M in 0.03 M H2SO4-methanol solution after 5 h on stream at −10°C and atmospheric pressure. This performance is due to high activity in the H2O2 synthesis reaction and low activities in the undesirable H2O2 decomposition and hydrogenation reactions. Good performance of the PdAu2/PSi catalyst was associated with the major part of Pd in the catalyst being in the form of the bimetallic Pd-Au nanoparticles. Porous silicon was concluded to be a promising catalytic support for direct hydrogen peroxide synthesis due to its inertness with respect to undesirable side reactions, high thermal stability, and conductivity, possibility of safe operation at high temperatures and pressures and a well-established manufacturing process.

Development of 2D MOF-Based Microrobots under Annealing Treatment and Their Biomedical Application

“…MOFs are composed of inorganic metal components combined with organic ligands through coordination bonds . Compared with other traditional porous materials (silicon-supported salts, zeolites, metal oxides, covalent organic framework (COF), etc. ), the most notable features of MOFs are their tunable surface area, pore size, and metal center .…”

Lanthanum-Modified MCF-Derived Nickel Phyllosilicate Catalyst for Enhanced CO2 Methanation: A Comprehensive Study

“…For example, the nickel phyllosilicate with a core–shell structure was prepared through the hydrothermal reaction of a silica sphere and nickel salts for dehydrogenation of 1,2-cyclohexanediol, which exhibited high activity and good stability . Amorphous silica materials with various morphologies can be classified into four types according to the different dimensions, such as zero-dimensional spheres, one-dimensional nanotubes, two-dimensional thin films, and three-dimensional (3D) networked monoliths. − Among them, the three-dimensional silica material has been seldom reported to synthetize phyllosilicate materials. Compared with the materials with the different dimensions, the 3D material can not only obtain a high surface area but also provide more diffusion paths for enhanced mass transfer, thereby avoiding blockage of the channel.…”

Catalytic Performance and Characterization of Highly Efficient Composite Ni(Clx)/CeO2/η‐Al2O3/FeCrAl Wire Mesh Catalysts for Preferential CO Methanation

“…XPS . The homemade XPS‐Calc program, previously tested on a number of systems was used for processing of spectral data. Figure presents the XPS survey spectra of the used SC1 and SC2 demonstrating the presence in the catalysts of such elements as C, O, Ni, Ce, Cl and Al (the Al2p peaks are not shown).…”