Non-thermal plasma reduction of iron oxide for iron fuel production

The use of iron as a recyclable metal fuel requires efficient, low-carbon reduction methods. This study examines the low-pressure non-thermal hydrogen plasma-assisted solid state reduction of iron oxide powders (45- 6 3 μ ⁢ m ). Reduction experiments were carried out in the range of 200–500 °C and 0–30 W plasma power using a low-pressure capacitively-coupled radiofrequency (RF) plasma system with argon-hydrogen gas mixtures. The extent of reduction and phase composition were quantified by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX), while surface morphology was characterized by scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). Plasma-assisted reduction increased iron yield in comparison to thermal-only reduction experiments. Morphological analysis revealed bubble formation attributed to water vapor production, and plasma-induced surface smoothing consistent with an annealing effect. Subsequent re-oxidation tests performed in a thermogravimetric analyzer (TGA) indicate an increased kinetic barrier to oxidation, which may have implications for handling stability and high-temperature combustion. These results demonstrate that low-power non-thermal hydrogen plasma can enhance iron oxide reduction while modifying its surface properties, supporting its potential for sustainable iron fuel production.