Flame Synthesis of Nanophase TiO_2 Crystalline Films

摘要

Nanophase TiO_2, due to its attractive catalytic and photocatalytic properties, has been successfully used in a variety of applications including electrochemical gas sensors, catalyst supports, and photovoltaic cells. Sol-gel and spray pyrolysis methods are often used in synthesizing TiO_2 nanoparticles, but typically result in amorphous particles with a wide distribution of particle sizes. In recent years, a novel method was developed which uses a premixed stagnation flame to synthesize single-crystal TiO_2 a few nanometers in diameter with ultra narrow size distributions. The size of the particles can be fine tuned by adjusting the Ti precursor concentration. In this work, we examine the feasibility of continuous deposition and processing of a TiO_2 particle thin film for gas sensor and photovoltaic applications. The properties of the thin film, including particle size, film thickness, morphology and density will be examined as a function of the synthesis conditions. The data is interpreted on the basis of flame dynamics, particle nucleation, growth and transport.