Study of ethanol reactions on H₂ reduced Au/TiO₂ anatase and rutile: effect of metal loading on reaction selectivity

Abstract

The effect of Au particle size and loading (over TiO 2 anatase and rutile) on the reaction selectivity and conversion of ethanol has been studied using temperature programmed desorption. The addition of Au onto TiO 2 had three main effects on the reaction. First, a gradual decrease is observed in the reaction selectivity of the dehydration (to ethylene) in favor of dehydrogenation (to acetaldehyde) with increasing Au loading on both polymorphs of TiO 2. Second, a gradual decrease is seen in the desorption temperature of the main reaction products also with increasing Au loading. Third, secondary reaction products [mainly C4 (crotonaldehyde, butene, furan) and C6 (benzene) hydrocarbons] increased considerably with increasing Au loading reaching about 60% for benzene for the 8 wt-%Au/TiO 2 anatase. An inverse relationship between the interface lengths of Au particles on TiO 2 and desorpion temperatures of reaction products is found.

Preparation and Characterization of PANI/TiO2 Composite for Photocatalytic Degradation of Tartrazine Dye

“…a) shows the XRD pattern of the prepared TiO 2 with peaks positioned at (2θ) = 26, 38, 48, 54, 62 and 70. This pattern confirms the formation of anatase phase with few rutile percentage appeared at positions (2θ) = 28, 32, 37 and 42[22]. The XRD software calculated weight percent of anatase and rutile phases are 80% and 20 % respectively.…”

On the role of metal particle size and surface coverage for photo-catalytic hydrogen production: A case study of the Au/CdS system

“…5 (b) the total number of Au particles were calculated from the mean size of Au particles present on Au/CdS using TEM images and the Au metal atom size (1.44 Å). Surface coverage was calculated from the area covered by each individual particle within a given distribution of metal particles normalized to total number of particles at each loading assuming that the area covered by single metal particle will be equal to the area inside its circumference [75]. It can be noted that Au enhances the rate of hydrogen production up to a loading of 3 wt.% Au.…”

Photocatalytic degradation of textile dyes on Cu2O-CuO/TiO2 anatase powders

“…The change in photocatalytic activity may not only arise from the geometric effect but also due to the electronic effects. In the latter case the metal particles can affect the activity away from them on the semiconductor surface [41,42].…”