Abstract
Turkish sepiolite-zirconium oxide mixtures were applied as a support for the silver catalyst in a soot combustion. Sepiolite-Zr-K-Ag-O catalyst was characterized by XRD, N2 adsorption, SEM, TPR-H2 and EGA-MS. The combustion of soot was studied with a thermobalance (TG-DTA). The modification resulted in a partial degradation of the sepiolite structure, however, the morphology was preserved. The adsorption of N2 of the modified sepiolite is a characteristic for mesoporous materials with a wide distribution of pores. The specific surface area SBET equals 83 m2/g and the pores volume is 0.23 cm3/g. The basic character of the surface centers of sepiolite is indicated by CO2 desorption (TPD-MS) at 170 °C and at about 620 °C due to a surface carbonates decomposition. The thermodesorption of oxygen at 650-850 °C indicates the decomposition of AgOx phases at the surface. The presence of AgOx phases is also confirmed by TPR-H2 spectrum (low temperature reduction peak at 130 and 180 °C). The high-temperature reduction at about 570 °C is probably related to Ag-O-M phases on the support. The soot combustion takes place at T50 = 575 °C. Without silver (sepiolite-Zr-K-O) T50 = 560 °C but sepiolite modified with silver (sepiolite-Zr-K-Ag-O) undergoes the same process at T50 = 490 °C.
Original language | English |
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Pages (from-to) | 291-296 |
Number of pages | 6 |
Journal | Applied Clay Science |
Volume | 32 |
Issue number | 3-4 |
DOIs | |
Publication status | Published - May 2006 |
Keywords
- Catalyst
- Sepiolite
- Silver
- Soot combustion
- Support
- Zirconium oxide