Abstract
Flame synthesis of V-doping TiO2 is studied by in situ diagnostic of phase selective laser-induced breakdown spectroscopy (LIBS). We apply this novel optical spectroscopy to tracing the gas-to-particle phase transition of V and Ti elements, as low-intensity laser only excites V and Ti atoms present in the particle phase but not in the gas phase. Both V and Ti atomic signals appear early at the burner exit and plateau downstream after a distance about 14 mm. Compared with signals in pure TiO2 synthesis, the signal of Ti in the doping synthesis is significantly strengthened due to the lower band gap of V-doped TiO2. The doping mechanism is then inferred from the observations. It is deduced that the substantial collision and mixing of the nucleated V and Ti oxides occur even at the burner rim and persist through the entire process. The signal intensities of both V and Ti atoms increase with laser power and tend to plateau at about 20 mJ/pulse. In the flatten region, the ratio of V and Ti signal intensities is almost proportional to the doping ratio of V and Ti elements in the particle phase, showing feasibility of utilizing the optical method in the doping ratio measurement.
Original language | English (US) |
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Pages (from-to) | 2283-2289 |
Number of pages | 7 |
Journal | Proceedings of the Combustion Institute |
Volume | 35 |
Issue number | 2 |
DOIs | |
State | Published - 2015 |
Event | 30th International Symposium on Combustion - Chicago, IL, United States Duration: Jul 25 2004 → Jul 30 2004 |
All Science Journal Classification (ASJC) codes
- General Chemical Engineering
- Mechanical Engineering
- Physical and Theoretical Chemistry
Keywords
- Flame synthesis
- Gas-to-particle conversion
- Phase-selective LIBS
- V-doped TiO