2026-10-14T05:26:05Z https://www.scidb.cn/oai

10.57760/sciencedb.j00124.00430 2026-08-07T11:04:17Z

2026-08-07 Screening of oxygen carriers for chemical looping CO2 conversion and hydrogen production based on Gibbs free energy doi:10.57760/sciencedb.j00124.00430 en Chemical looping, with its advantages of efficient product separation and low energy consumption, has emerged as a crucial technical pathway for the CO2 conversion and hydrogen production via water splitting. Oxygen carriers, functioning within the chemical looping cycle, undertaking oxygen storage and transfer and participating in the redox reactions, serve as a key component that determines the reaction rates and product selectivity. To screen high-performance oxygen carriers, this study employed the Gibbs free energy analysis method to thermodynamically investigate the chemical looping reactions involving typical metals and corresponding oxides for the CO2 conversion and hydrogen production via water splitting. Based on the Ellingham diagrams, the feasibility of the conversion reactions and the performance of various metal-based oxygen carriers were evaluated. The Gibbs free energies for the oxidation of metals (such as iron, vanadium, manganese, cobalt, copper, and cerium) and that for the reactions between these metals and water were obtained. The feasibility and critical temperatures of the reactions of various metals and their oxides with CO2 and water across different temperature ranges were clarified, which revealed the superior capability of the Fe/Mn-based oxygen carriers for CO2 reduction at high temperatures and the great hydrogen production potential of Mn/Cu/Ce-based oxygen carriers at low temperatures. The results indicate that high temperatures can promote the reduction of CO2 by iron, manganese, and their reduced oxides, with initial reaction temperatures of 708 °C for Fe and 935°C for Mn; in addition, the promoting effect becomes more pronounced at higher temperatures. Thermodynamically, manganese, copper, and cerium can spontaneously decompose water to produce hydrogen at relatively low temperatures. This study delineates the relative redox performance of various metals with CO2 and H2O at different temperatures, providing a thermodynamic theoretical basis for the screening and optimization of oxygen carriers in the chemical looping reactions. Gibbs free energy; chemical looping reactions; carbon dioxide conversion; hydrogen production by water splitting; oxygen carriers 胡强 王鹏 PUBLIC https://creativecommons.org/licenses/by-sa/4.0/ dataset Science Data Bank