Catalytic effect of laser-combined atmospheric pressure plasma in lowering the reduction temperature of hematite

Atmospheric pressure plasma (APP) generates highly reactive species that are useful for surface activation. We demonstrate a fast regeneration of iron oxides, that are popular catalysts in various industrial processes, using microwave-driven argon APP under ambient conditions. The surface treatment of hematite powder by the APP with a small portion of hydrogen (0.5 vol%) lowers the oxide's reduction temperature. A near-infrared laser is used for localized heating to control the surface temperature. Controlled experiments without plasma confirm the catalytic effect of the plasma. Raman, XRD, SEM, and XPS analyses show that the plasma treatment changed the chemical state of the hematite to that of magnetite without sintering.

Automated summary

The study demonstrates the regeneration process of iron oxide catalysts using atmospheric pressure plasma technology, with hematite powder exposed to microwave-driven argon plasma being transformed into magnetite. The addition of hydrogen during the surface treatment process lowers the reduction temperature, and controlled experiments confirm the catalytic effect of the plasma on the chemical state of the hematite.