Insight into the efficient oxidation of methyl-ethyl-ketone over hierarchically micro-mesostructured Pt/K-(Al)SiO2 nanorod catalysts: Structure-activity relationships and mechanism

Abstract

Hierarchically micro-mesostructured Pt/K-Al-SiO2 catalysts with regular nanorod (Pt/KA-NRS) and spherical nanoflower-like (Pt/KA-SNFS) morphologies were prepared. The existence of Al atoms generates Brønsted acid sites and reduces silanol groups over the supports, promoting the dispersion of Pt nanoparticles and stability of catalysts. Potassium atoms balance the negative charge of supports and enhance O2 mobility. The Pt/KA-NRS catalysts exhibit unexceptionable low temperature activity, CO2 selectivity, and stability for MEK oxidation. Amongst, 0.27 wt.% Pt/KA-NRS completely converts MEK at just 170 °C (activation energy as low as 37.22 kJ• % mol −1), more than 100 °C lower than other typical Pt/Pd supported catalysts reported in the literature. Diacetyl and 2,3-butandiol are the main intermediates during MEK activation, which convert into H2O and CO2 through aldehydes and acids. The excellent catalytic activity of Pt/KA-NRS is ascribed to their regular morphology, high Pt 0 content and dispersion, excellent MEK adsorption capacity and superior O2/CO2 desorption capability under low temperature.

SO2 promoted in situ recovery of thermally deactivated Fe2(SO4)3/TiO2 NH3-SCR catalysts: From experimental work to theoretical study

“…Several bands were observed in the spectrum of FeTi material after exposure to NH3 for 15 min and purged with N2 for another 10 min. The band at 1445 cm −1 and the broad band from 1635 to 1850 cm −1 were assigned to NH4 + species chemisorbed onto Brønsted acid sites [49,50]. The band at 1601 cm −1 was indicative of NH3 adsorbed onto Lewis acid sites [49,50].…”

“…The band at 1445 cm −1 and the broad band from 1635 to 1850 cm −1 were assigned to NH4 + species chemisorbed onto Brønsted acid sites [49,50]. The band at 1601 cm −1 was indicative of NH3 adsorbed onto Lewis acid sites [49,50]. The bands at 1380, 1335 and 1280 cm −1 were attributed to NH2 wagging [51,52].…”

Sword-like CuO/CeO2 composites derived from a Ce-BTC metal–organic framework with superior CO oxidation performance

“…Three different peaks at the BE of 533.6, 531.6 and 529 eV are ascribed to surface adsorbed oxygen species (O ads ), surface hydroxyl oxygen species (O OH ), and surface lattice oxygen (O latt ), respectively. [28][29][30][31][32][33] It is found that the concentration of lattice oxygen O ads /(O latt + O OH ) of CuCeO-5 is highest than other three CuO/CeO 2 catalysts.…”

Surface Modification of Cobalt‐Manganese Mixed Oxide and Its Application for Low‐Temperature Propane Catalytic Combustion

“…Meanwhile, the lattice oxygen species belonged to the oxygen inside the crystal and had the strong bonding in the lattice phase, which resulted in the hard desorption of the lattice oxygen species. [39,30] One could see that several types of oxygen species occupied the temperature region of 50-200°C, 200-450°C, 450-700°C and above 700°C, which could be registered for physically adsorbed oxygen(O α ), surface chemically absorbed oxygen(O β ), surface lattice oxygen (O γ ), and the bulk lattice oxygen(O δ ), respectively. [40] Furthermore, xM-Co 3 Mn 1 (x > 0) displayed obvious desorption peak under the temperature process below 450°C, whose peak intensity was much stronger than 0 M-Co 3 Mn 1 , meaning that more defective oxygen existed on the surface of xM-Co 3 Mn 1 (x > 0).…”