Effect of Potassium Doping on the Structural and Catalytic Properties of V/Ti-oxide in sSelective Toluene Oxidation
Full article
| Общее |
Language:
Английский,
Genre:
Full article,
Status:
Published,
Source type:
Original
|
| Journal |
Applied Catalysis A: General
ISSN: 0926-860X
, E-ISSN: 1873-3875
|
| Output data |
Year: 2000,
Volume: 202,
Number: 2,
Pages: 243-250
Pages count
: 8
DOI:
10.1016/S0926-860X(00)00538-X
|
| Tags |
V/Ti-oxide catalysts; Doping by potassium; Toluene partial oxidation; Transient response technique; FT-Raman spectroscopy; HRTEM51V NMR |
| Authors |
Bulushev Dmitri A.
1
,
Kiwi-Minsker Lioubov
1
,
Zaikovskii Vladimir I.
2
,
Lapina Olga B.
2
,
Ivanov Alexei A.
2
,
Reshetnikov Sergei I.
2
,
Renken Albert
1
|
| Affiliations |
| 1 |
Institute of Chemical Engineering, Swiss Federal Institute of Technology
|
| 2 |
Boreskov Institute of Catalysis
|
|
Funding (2)
|
1
|
European Commission
|
|
|
2
|
Swiss National Science Foundation
|
|
Small addition of potassium to V/Ti-oxide catalyst (K:V=0.19), consisting of 3.7 monolayer VOx, increased activity and selectivity in partial oxidation of toluene. In order to elucidate the nature of vanadia species formed on the surface of V/Ti-oxide upon potassium doping, the catalysts were studied by transient kinetics method. The transient product responses during toluene oxidation by the oxygen present in the catalyst were compared for K-doped and non-doped samples. The formation of CO2 decreased and formation of benzaldehyde increased with addition of potassium. This suggests a lower surface concentration of electrophilic oxygen (O−, O2−), which is usually responsible for the deep oxidation, and a higher concentration of nucleophilic oxygen (O2−), responsible for the partial oxidation.
The catalysts were characterised by means of HRTEM, FT-Raman spectroscopy and 51V NMR. Potassium addition introduces a disorder in the crystalline structure of bulk V2O5 particles resulting in better spreading of V2O5 over TiO2 surface. The interaction of V2O5 with TiO2 was facilitated upon K-doping, leading to the increased formation of monomeric vanadia species, which are the active sites in toluene partial oxidation to benzaldehyde.