Mixed Metal Oxide Alloys
ADEM’s custom designed fluidized bed reactor is employed to coat nanoparticles in gas phase and using liquid phase precursors. The process is highly adaptable to several precursors chemicals like nitrates, acetates, oxalates, alkoxides, etc. and solvents such as water, alcohol and others, which can be easily incorporated into the spray feedstock. Precursor solution mixtures can be used to produce multi-component systems, such as bimetallic and ternary oxides and their alloys. This technology also allows for controlling the size of resulting particles to be sub-10 nm and the resulting powder is dispersible. The underlying concept for making multi-component metal oxide alloys is through plasma oxidation of liquid droplets containing mixtures of metal precursors.
Liquid precursors are injected at the bottom through a nozzle and sprayed on to highly dense oxygen rich microwave plasma discharge with vertically upward flow confined in a conical cavity. The micron size droplets, when sprayed into hot oxygen plasma, instantly oxidizes and solidifies upon exiting the flame region. The resulting powder is collected in a bag house filter. The rapid time scale allows for bulk manufacturing, high throughput and combinatorial screening of oxide materials for catalysts. The technique has already been demonstrated with ternary, quaternary and alloys with five elements and compositional control in solid solutions, pyrochlores, perovskites in addition to rocksalt and spinel phases. Such materials can be used to design high performance catalysts.