CO2reforming of methane over argon plasma reduced Rh/Al2O3catalyst: a case study of alternative catalystreductionvia non-hydrogen plasmas

Abstract

An argon glow discharge plasma was used to reduce RhCl₃ impregnated Al₂O₃ powder at room temperature. The obtained sample was characterized by chemisorption, X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) equipped with an energy dispersion X-ray spectrometer (EDX). XRD and EDX analyses confirmed that Rh ions were reduced into metallic Rh during the plasma reduction. TEM analysis revealed that the argon plasma reduction induces a high dispersion of Rh nano-particles. The average particle size of Rh is 1.2 nm, estimated by chemisorption. For the CO₂ reforming of methane, the plasma reduced Rh/Al₂O₃ shows comparable activity to a conventional hydrogen reduced catalyst. The value of the standard electrode potential can be employed for the assessment of reducibility of metal ions. The catalyst reduction using argon glow discharge plasma at room temperature will provide a promising alternative to hydrogen reduction for catalyst preparation.