Synergistic enhancement of chemical looping-based CO2 splitting with biomass cascade utilization using cyclic stabilized Ca2Fe2O5 aerogel

Abstract

Thermochemical splitting of carbon dioxide to carbon-containing fuels or value-added chemicals is a promising method to reduce greenhouse effects. In this study, we propose a novel process for synchronous promotion of chemical looping-based CO₂ splitting with biomass cascade utilization. The superiority of the process is reflected in (1) a biomass fast pyrolysis process is carried out for syngas, phenolic-rich bio-oil, and biochar co-production with oxygen carrier reduction; (2) the reduced oxygen carrier and the biomass-derived biochar were both applied for CO₂ splitting during the oxygen carrier oxidation stage with carbon monoxide production as well as oxygen carrier re-oxidation; (3) the redox looping of the oxygen carrier was found to synchronously promote the comprehensive utilization of biomass and CO₂ splitting to CO. Various characterizations e.g. HRTEM- and SEM-EDX mapping, H₂-TPR, CO₂-TPO, XRD, XPS, N₂ nitrogen adsorption and desorption isotherm tests, Mössbauer, etc. were employed to elucidate the aerogels' microstructures, phase compositions, redox activity, and cyclic stability. Results indicate that the Ca₂Fe₂O₅ aerogel is a promising initiator of the proposed chemical looping process from the perspectives of biomass utilization efficiency, redox activity, and cyclic durability.