A Common Factor Determining the Features of the Photocatalytic Hydrogenation and Isomerization of Alkenes over Ti–Si Oxides

Abstract

On addition of SiO2 to TiO2 photocatalysts, it has been found that the yields of C2H6 and CH4 in the photocatalytic hydrogenation of propylene as well as that of 1-butene in the photocatalytic isomerization of cis-2-butene decrease simultaneously. This gives some support for the mechanisms for both reactions where [Ti3+–O−] pairs are important.

Photocatalytic Hydrogenation on Semiconductor Particles

“…The hydrogenation to ethane was efficiently occurred upon the bimetal/TiO2, on which the role of the latter metals (Ni or Cu) was to suppress the hydrogen production as side reaction. Titanium-silicon (Ti/Si) binary oxides were prepared and utilized for the photocatalytic hydrogenation of alkenes and alkynes with H2O by Anpo's group [20][21][22]. The reactivity and selectivity for the hydrogenation of CH3C≡CH were investigated as a function of the Ti content [21,22].…”

Ultra-thin SiO2 layers on TiO2: improved photocatalysis by enhancing products' desorption

“…3 There are many documented cases in which not only that the presence of silica was not detrimental but, in fact, assisted to enhance photocatalysis. [11][12][13] In certain cases, the observed enhanced photocatalytic properties in TiO 2 -SiO 2 binary mixtures were explained in terms of suppressing the anatase-to-rutile transformation during calcination, leading to higher crystallinity of the photocatalyst. 14 However, in most cases where such benevolent effect was found, the effect was attributed to improved mass transfer.…”

Characteristics of the Phosphorescence Spectra of Benzophenone Adsorbed on Ti−Al Binary Oxides

“…On the other hand, it can be expected that absorption and photoluminescence spectra measurements (fluorescence and phosphorescence) on adsorbed molecules provide useful information on the physical and chemical nature of the adsorption sites or surfaces. Various host−guest systems offer interesting areas of research, and spectroscopic techniques have been successfully used to study such systems. − …”

“…It is known that various binary oxide catalysts often exhibit higher catalytic activity and selectivity than what can be predicted from the properties of their components. , Therefore, it is of special interest to study the relationship between the structure of the binary oxides and the photophysical and photochemical behavior of the molecules adsorbed. In addition to this, with binary oxides, it is possible to obtain detailed information on these relationships by changing the composition of the binary oxides continuously and systematically from 0 to 100%. , However, few studies have been performed on binary oxides from this point of view.…”

“…Various host-guest systems offer interesting areas of research, and spectroscopic techniques have been successfully used to study such systems. [36][37][38][39] It is known that various binary oxide catalysts often exhibit higher catalytic activity and selectivity than what can be predicted from the properties of their components. 38,39 Therefore, it is of special interest to study the relationship between the structure of the binary oxides and the photophysical and photochemical behavior of the molecules adsorbed.…”