Experimental Microkinetic Approach of De-NO_x by NH₃ on V₂O₅/WO₃/TiO₂ Catalysts. 4. Individual Heats of Adsorption of Adsorbed H₂O Species on Sulfate-Free and Sulfated TiO₂ Supports

Abstract

Experimental. Solids, characterizations and pretreatmentsIn the present study, the sulfate free and sulfated TiO 2 solids are P25 from Degussa (55 m 2 /g) and DT51 (80 m 2 /g) from Millenium Inorganic Chemical respectively which have been (a) used as supports of NH 3 -SCR catalysts and (b) characterized considering their a = 18 torr) on TiO 2 -P25 and Al 2 O 3 have been ascribed by Kakeuchi et al. 15 to d-H and Hbond IR bands respectively of polymeric H 2 O chains. It must be noted that the positions of the d-H IR bands, 36-37 are in the same wavenumber range than the OH groups of the metal oxides and the ν 1 and ν 3 IR bands of isolated H 2 O species, 11-17 leading to difficulties in the interpretation of the IR spectra of adsorbed H 2 O species.

Unravelling water effects on solid acid catalysts: Case study of TiO 2 /SiO 2 as a catalyst for the dehydration of isobutanol

“…Finally, in situ-FTIR acidity measurements under NH 3 and/or water vapor flow (P NH3 0-1%,P H2O 0-3%) were achieved with Nicolet 6700 (ThermoScientific) spectrometer in a IR cell reactor specially designed to limit the gas phase contribution [28]. Indeed, its optical path of only 2.2 mm allowed relevant data to be obtained in the temperature range 293-800 K under water vapor [29].…”

Acidic Properties of Alkaline-Earth Phosphates Determined by an Experimental-Theoretical Approach

“…RT) was assigned to (H 2 O) due to traces of physisorbed water leading to the spontaneous reaction: 16,39 NH 3 + H 2 O ads  (NH 4 + ) ads + OHads Such reaction which did occur only at 7 °C also explained observation of the bending   (NH 4 + ) and   (NH 4 + ) vibrations bands at 1475 and 1685 cm -1 , respectively. 49,50 The latter one is observed by IR only when symmetry of NH 4 + cations is lower than T d .…”

The Pivotal Role of Catalysis in France: Selected Examples of Recent Advances and Future Prospects.

“…These models allow to incorporate kinetic information from different experiments, such as surface science or temperature‐programmed experiments, or from computational chemistry. Examples of this approach are DeNO x by NH 3 and CO oxidation in catalytic converters . Microkinetics is also applied increasingly by theoretical chemists to link DFT studies with experimental kinetic data .…”