Adsorption and surface reactions of acetone vapor were observed on the title oxides at room higher temperatures (up to 400 °C), using in situ infrared spectroscopy. The results correlated with spectroscopy adsorbed pyridine, assess impacts acid−base properties. It was found that availability Lewis acid sites is essential for anchoring molecules surface. Coexisting base catalyze condensation into mesityl oxide species, via formation subsequent decomposition enolate diacetone alcohol species....

In this investigation, well defined mesoporous zirconia nanoparticles (ZrO2 NPs) with cubic, tetragonal or monoclinic pure phase were synthesized via thermal recovery (in air) from chitosan (CS)- polyvinyl alcohol (PVA)-ZrOx hybrid films, prepared using sol-gel processing. This facile preparative method was found to lead an almost quantitative of the ZrOx content film in form ZrO2 NPs. Impacts temperature (450, 800 and 1100 °C) polymer type (natural bio-waste CS synthetic PVA) used...

Pure ceria powders, CeO2, were synthesized in heptane-microemulsified aqueous solutions of CeCl3 or Ce(NO3)3 stabilized by AOT (sodium bis(2-ethylhexyl) sulfosuccinate), DDAB (di-n-didodecyldimethylammonium bromide), + Brij 35 surfactant mixtures. Micellar DTAB (n-dodecyltrimethylammonium bromide) and vesicular systems also used as media for generating CeO2. Characterization the powders X-ray powder diffractometry, laser-Raman spectroscopy, Fourier transform infrared spectroscopy revealed...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLow-temperature carbon monoxide adsorption and state of molybdena supported on alumina, titania, ceria, zirconia. An infrared spectroscopic investigationM. I. Zaki, B. Vielhaber, H. KnoezingerCite this: J. Phys. Chem. 1986, 90, 14, 3176–3183Publication Date (Print):July 1, 1986Publication History Published online1 May 2002Published inissue 1 July 1986https://pubs.acs.org/doi/10.1021/j100405a026https://doi.org/10.1021/j100405a026research-articleACS...

Pathways and generated surface species of adsorption consequent reactions acetone vapor on characterized silica, alumina, ∼5 wt % silica−alumina were examined by in-situ infrared (IR) spectroscopy, following degassing at room (RT) higher temperatures (100−400 °C). For reference confirmatory purposes, adsorptives mesityl oxide acetic acid, adsorbents K-modified pyridine-covered silica−alumina, employed. In the absence Lewis Bronsted acid sites, as well basic sites (i.e., silica), molecules...

Infrared spectroscopy has been used to analyse the gas-phase reaction products, and related adsorbed species, obtained from decomposition of methanol over TiO2, ZrO2 or HfO2 catalysts after consecutive 10 min heating periods at 50 °C intervals between room temperature 400 °C. Somewhat different results were a 500 calcined TiO2 catalyst (hydroxylated anatase surface) an 800 one (dehydroxylated rutile surface). The had dehydroxylated surfaces, monoclinic in crystal structure, gave products...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHighly dispersed rhodium on alumina catalysts: influence of the atmosphere state and dispersion rhodiumM. I. Zaki, G. Kunzmann, B. C. Gates, H. KnoezingerCite this: J. Phys. Chem. 1987, 91, 6, 1486–1493Publication Date (Print):March 1, 1987Publication History Published online1 May 2002Published inissue 1 March 1987https://pubs.acs.org/doi/10.1021/j100290a041https://doi.org/10.1021/j100290a041research-articleACS PublicationsRequest reuse...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid/solid interactions. Monolayer formation in molybdenum trioxide-alumina physical mixturesJ. Leyrer, M. I. Zaki, and H. KnoezingerCite this: J. Phys. Chem. 1986, 90, 20, 4775–4780Publication Date (Print):September 1, 1986Publication History Published online1 May 2002Published inissue 1 September 1986https://pubs.acs.org/doi/10.1021/j100411a013https://doi.org/10.1021/j100411a013research-articleACS PublicationsRequest reuse permissionsArticle...

New insight was gained into the acidity-reactivity relationships of sulfated zirconia (SZ) catalysts prepared via (NH4)2SO4 impregnation Zr(OH)4 for propanoic acid esterification with methanol. A family systematically related SZs characterized by bulk and surface analyses including XRD, XPS, TGA-MS, N2 porosimetry, temperature-programmed propylamine decomposition, FTIR adsorbed pyridine, as well methylbutynol (MBOH) a reactive probe molecule. Increasing sulfation induces transition from...

The dehydrogenation and dehydration reactions of ethanol over TiO2, ZrO2 or HfO2 catalysts has been monitored in the gas phase on surfaces by infrared spectroscopy. reaction pathways closely parallel those methanol reported prevous paper (Part 2) with addition direct C2H5OH → C2H4+ H2O production benzene as a minor product. spectroscopic analysis decomposition diethyl ether initial reagent TiO2(500) catalyst confirms that ethane product is derived from precursor. As methane methanol, it...

Infrared spectroscopy has been used to analyse the gas-phase reaction products and related adsorbed species obtained between room temperature 400 °C from dehydrogenation/dehydration reactions of propan-2-ol over a series differently calcined catalysts TiO2, ZrO2 HfO2. The HfO2 results were independent calcination pretreatment, surfaces these oxides, like that TiO2 sample at 800 °C, dehydroxylated. Different 300 which had hydroxylated surface. acidic sites reactivities TiO2(300 °C) TiO2(800...