Spinel MnFe2O4 nanoparticles (MFO-NPs) for CO2 cyclic decomposition prepared from ferromanganese ores

Abstract Ferromanganese ores with high contents of Mn and Fe are abundant worldwide. In this study, spinel-type MnFe2O4 nanoparticles (MFO-NPs) were first synthesized via a novel solid-state reaction process followed by ball-milling, magnetic separation, and nano-grinding. The synthetic MFO-NPs presented a stable spinel structure, fine granularity, and large specific surface; these characteristics highlight their potential in the preparation of thermochemical catalysts. We additionally conducted H2 reduction (HR) and CO2 decomposition reaction (CDR) cyclic tests to investigate the catalytic performance of MFO-NPs. The MFO-NPs showed excellent recyclability and thermal stability during CO2 decomposition; moreover, oxygen-defect MFO-NPs were able to completely decompose CO2 into carbon quantum dots. The mechanism of CO2 decomposition on the MFO-NPs’ surfaces was analysed in detail by XRD, SEM, TEM, TG, Raman, XPS.