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Keywords:

  • flame synthesis;
  • mixed metal oxides;
  • structural and catalytic properties;
  • vanadium

Abstract

In the past two decades flame aerosol synthesis of novel materials has experienced significant growth in both industry and academia. Recent research is focused on the development of new materials in the nanosized range to be used in various applications, such as catalysts, gas sensors, pigments, and batteries. Several studies indicate that this scalable synthesis method can result in novel and metastable phases of mixed metal oxides of high purity, which may not be easy accessible by conventional wet- or solid-state processes. Especially for catalytic applications this synthesis method is emerging as an attractive fast and single-step production route for high surface area materials, often with unprecedented structural and catalytic properties. The large variety of possible organometallic precursors especially for the liquid-fed aerosol flame synthesis makes this technique very versatile for catalyst synthesis.

Using the example of the widely used vanadia-based mixed oxide catalysts, we analyze the structural and catalytic properties of flame-derived catalysts and compare them to corresponding catalysts prepared by classical wet-chemistry methods. The often unique structural properties along with their control at proper synthesis conditions and their influence on catalyst performance in selected reactions are discussed. Subsequently, we give an overview of other recent flame-made mixed metal oxide based catalysts and make an attempt to assess the potential and limitations of flame synthesis for the preparation of catalytic mixed metal oxide materials, and finally we identify future challenges in research.