Synthesis and characterization of Au nano particles supported catalysts for partial oxidation of ethanol: Influence of solution pH, Au nanoparticle size, support structure and acidity

Supported Gold Nanoparticles as Catalysts for the Oxidation of Alcohols and Alkanes

“…A constraint of the deposition-precipitation is that it is not very suitable for activated carbon (Prati and Martra, 1999; Haruta, 2003; Carabineiro and Thompson, 2007, 2010; Prati and Villa, 2012) or zeolites (Lin and Wan, 2003), due to their high isoelectric point [although some recent publications showed better results for these materials, especially after an acidic treatment (Cardenas-Lizana et al, 2015; Behravesh et al, 2017)]. Deposition-precipitation has the advantage over co-precipitation in that all of the active component remains on the surface of the support and none is buried within it (Bond and Thompson, 1999; Wang et al, 2003; Carabineiro and Thompson, 2007).…”

New trends in tailoring active sites in zeolite-based catalysts

“…As it occurs for other support materials, the pH of the solution during the deposition of gold not only controls the zeolite surface charge but also the extent of hydrolysis of the AuCl4precursor and, consequently, the nature of the precursor-zeolite interaction. Behravesh et al 215 performed a systematic investigation of the effect of the solution pH (adjusted by adding an NH4OH solution as precipitating agent) on the final particle size and size distribution, and loading efficiency for Au deposited on HY zeolite (Si/Al ratio of 40) and their consequences on the activity for the gas phase oxidation of ethanol. In the investigated pH range of 6.5 -10.5, the surface of the HY zeolite was found to be negatively charged, preventing an efficient electrostatic interaction of the 216 The so generated positive surface charge favoured the electrostatic interaction between the anionic Au species and the zeolite surface, resulting in ultrasmall gold nanoparticles of ∼1 nm confined in the supercages of the FAU-type zeolite that exhibited a much higher reactivity for CO oxidation compared to Au nanoparticles deposited on untreated HY.…”

Synthesis and Characterization of Metal Modified Catalysts for Decomposition of Ibuprofen from Aqueous Solutions

“…First, a thin pellet disc of the catalyst was pressed, installed into the FTIR cell, and heated up to 450 • C for 1 h. Then, the temperature was lowered to 100 • C, background spectra of the pellet were recorded, and pyridine was adsorbed on the catalyst sample for 30 min and desorbed consequently by discharge at 250, 350, and 450 • C, correspondingly. The pyridine desorption at 250-350 • C displays weak, medium, and strong sites, 350-450 • C indicate medium and strong sites, and 450 • C indicates strong sites [49]. X-ray diffraction patterns of the catalysts were recorded on a Panalytical X'Pert 3 Powder diffractometer with a CuK α (λ = 1.5406 Å) source.…”