Science Seminars

Reduction of metal oxides by heating graphite or multi-walled carbon nanotubes in a microwave oven

Derek and Melinda Hoyt

Microwave heating of a metal oxide in the presence of carbon in the form of graphite and multi-walled carbon nanotubes results in the reduction of the metal oxide to the neutral metal and, when using carbon nanotubes, the formation of metal nanowires, nanorods, and nanocubes. Depending on the solubility of carbon in the metal matrix, the reduced metal matrix may contain carbides, amorphous carbon, or a network of carbon nanotubes. The use of microwave heating of carbon to reduce metal oxides addresses three important aspects of metallurgy: 1) energy usage, 2) material performance, and 3) formation of metal containing nanomaterials. In the summer of 2013 Derek and Melinda Hoyt worked at the Ames National Laboratory to study the reduction of a variety of metal oxides under various conditions to determine practical limits of the reducing power of graphite and carbon nanotubes under microwave heating. A number of variables were studied in an attempt to elucidate mechanisms for the reduction of the metal oxide and for the formation of metal containing nanomaterials. From these studies proposed chemical mechanisms were developed. LeTourneau University is unique in its offering of a patented single-mode microwave welding technology that will allow continuing studies beyond the summer work that is discussed in this presentation.