Chemical and physical behavior of CoFe2O4 in steam–iron process with methanol

Abstract

In this paper we report on the use of CoFe2O4 spinel for the chemical loop processing for hydrogen production from methanol as the reducing species. The process is based on two steps: (i) the reduction of the spinel carried out with an organic fuel, with generation of a stream containing CO, CO2, H2O, and H2, followed by (ii) the recovery of the original material oxidation state by means of a re-oxidation with water, which leads to hydrogen production. Results of characterization carried out by Mössbauer spectroscopy and X-ray diffraction on the material as-synthesized and at different reduction degrees, and results of reactivity experiments during each one of the mentioned steps, are reported and put into perspective. We found that the complete recovery of the initial oxidation state was indeed not possible with only water, and a third step, with the partial re-oxidation of the material with air was needed for a completion of the cycle.