Aerosol flame synthesis of catalysts

A review of synthesis and performance of flame-made catalytic materials is presented. Emphasis is placed on flame technology for its dominance in aerosol manufacturing of materials of high purity with minimal liquid byproducts. Flame aerosol processes are characterized in terms of the precursor state supplied to the flame. During the last decade, a better understanding of aerosol and combustion synthesis of materials contributed to the development of one-step, dry synthesis of catalysts that are prepared conventionally by multi-step wet-phase processes. This includes TiO2-based photocatalysts, mixed oxides (e.g. V2O5/TiO2, TiO2/SiO2, perovskites, etc.) as well as supported metals (e.g. Pt/TiO2, Pd/Al2O3, Pt/CeO2/ZrO2, Pt/Ba/Al2O3, Ag/ZnO, Cu/ZnO/Al2O3 bimetallic Pd/Pt/Al2O3 and Au/TiO2) made by single- or multi-nozzle flames. In general, highly crystalline and non-porous nanoparticles are formed during flame synthesis, resulting in materials with high thermal stability. Unique particle structures, only available through aerosol processes, lead to improved performance in various catalytic applications.