Synthesis of Titanium Dioxide Aerosol Gels in a Buoyancy-Opposed Flame Reactor


Aerosol gels are a novel class of materials with potential to serve in various energy and environmental applications. In this work, we demonstrate the synthesis of titanium dioxide (TiO2) aerosol gels using a methane-oxygen coflow diffusion flame reactor operated in down-fired configuration (fuel flow in the direction opposite to buoyancy forces). Titanium tetraisopropoxide was fed as a precursor to the flame under different operating conditions. Control of the monomer size and crystalline phase of TiO2 gel particles was achieved by adjusting the flame operating conditions, specifically the flame temperature, which was shown to significantly influence the phase transformation and rate of particle growth and sintering. The resulting materials were characterized for their physical and optical properties. Results showed that the TiO2 aerosol gels had effective densities in the range 0.021-0.025 g/cm3, which is 2 orders of magnitude less than the theoretical mass density of TiO2. The monomer size distribution, crystalline phase, and UV-Vis absorbance spectra of the gels showed distinct characteristics as a function of flame temperature.


Civil, Architectural and Environmental Engineering


This research was supported by the National Science Foundation (NSF) under Grant no. CBET-1511964. Use of the Bruker d8 Advance X-ray diffractometer in Earth and Planetary Sciences at Washington University in St. Louis is supported by NSF Grant no. EAR-1161543.

Keywords and Phrases

Aerosols; Atmospheric movements; Buoyancy; Crystalline materials; Gels; Monomers; Optical properties; Oxides; Sintering; Synthesis (chemical); Titanium; Titanium dioxide; Coflow diffusion flames; Different operating conditions; Environmental applications; Flame temperatures; Operating condition; Orders of magnitude; Resulting materials; Titanium tetraisopropoxide; Flame synthesis; Monomer; Titanium dioxide; Aerosol; Aerosol gel; Article; Comparative study; Diffusion; Flame; Flow rate; Gel; Gelation; High temperature; Low temperature; Priority journal; Roentgen spectroscopy; Scanning electron microscopy; Synthesis

International Standard Serial Number (ISSN)

0278-6826; 1521-7388

Document Type

Article - Journal

Document Version


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© 2015 American Association for Aerosol Research, All rights reserved.

Publication Date

01 Dec 2015