Elena Montejano-Nares, Blanca Martínez-Navarro, Eva Castillejos López, Esther Asedegbega-Nieto, Ángel Maroto Valiente, José M. Conesa Alonso, Inmaculada Rodríguez Ramos, Antonio R. Guerrero Ruíz, Francisco Ivars-Barceló

Chemical Engineering Journal. Volume 474, 15 October 2023, 145373


Significant activity for the direct transformation of methane and carbon dioxide into coupling products (acetone and dimethyl ether), avoiding the dry reforming reaction which mainly dominates the processes reported so far, is proved. The approach has consisted in the development of a rationally designed multifunctional catalysts with capability for activation and selective transformation of methane and carbon dioxide at low reaction temperatures and below ambient pressure. The developed material integrates three distinguished phases (non-stoichiometric mixed iron oxide, Pd and Ag alloy, and noble metal oxide), as confirmed by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray energy dispersive spectroscopy of areas selected (SA-EDS) by field emission scanning electron microscopy (FESEM), as well as by synchrotron radiation X-ray absorption spectroscopies (EXAFS-XANES). Using a closed recirculating reaction system with a CH4/CO2 reactant gas mixture of 50/50 M ratio at 20 mbar, reaction rates within the order of 10-1 mol of CH4 converted per hour and kilogram of catalyst were achieved for the 25–150 °C studied temperature range. Combining experimental reactivity results with theoretical simulation studies, acetone and dimethyl ether were determined as primary and secondary reaction products, respectively. This study has an actual potential to revitalize the economic interest in the harnessing of methane and carbon dioxide, as a thread of hope towards eradicating their indiscriminate emissions, mainly involved in the relentless global warming and its devastating consequences.