Fe₂O₃@La_xSr_1−xFeO₃ Core–Shell Redox Catalyst for Methane Partial Oxidation

Abstract

Efficient and environmentally friendly conversion of methane into syngas is a topic of practical relevance for the production of hydrogen, chemicals, and synthetic fuels. At present, methane‐derived syngas is produced primarily through the steam methane reforming processes. The efficiencies of such processes are limited owing to the endothermic steam methane reforming reaction and the high steam to methane ratio required by the reforming catalysts. Chemical looping reforming represents an alternative approach for methane conversion. In the chemical looping reforming scheme, a solid oxygen carrier or “redox catalyst” is used to partially oxidize methane to syngas. The reduced redox catalyst is then regenerated with air. The cyclic redox operation reduces the steam usage while simplifying the heat integration scheme. Herein, a new Fe2O3@LaxSr1−xFeO3 (LSF) core–shell redox catalyst is synthesized and investigated. Compared with several other commonly investigated iron‐based redox catalysts, the newly developed core–shell redox catalyst is significantly more active and selective for syngas production from methane. It is also more resistant toward carbon formation and maintains high activity over cyclic redox operations.

Advanced Chemical Looping Materials for CO2 Utilization: A Review

“…This approach provides a promising strategy, not only to address the stability requirement, but also to improve the performance in terms of reactivity, redox properties and coke resistance, depending on the employed shell materials. Such core-shell structured nanomaterials have shown excellent performance in methane reforming [117,118,138,139,140] and chemical looping processes [14,40,119,120,121,122,123,124,141]. …”

Reduction kinetics of lanthanum ferrite perovskite for the production of synthesis gas by chemical-looping methane reforming

“…The challenge of NiO based redox catalysts, however, is their high tendency for coke formation, high cost, and health concerns (Adanez et al, 2012;Neal et al, 2014). Fe-based oxides have the advantages of being cheaper, low agglomeration, high melting point and more environmentally benign (Cabello et al, 2014a;Adanez et al, 2012;Neal et al, 2014Neal et al, , 2015Shafiefarhood et al, 2014;Galinsky et al, 2015). However, iron oxide based redox catalysts are not particularly active for methane oxidation (Cabello et al, 2014a;Shafiefarhood et al, 2014), and tend to have low selectivity toward methane partial oxidation.…”

“…Fe-based oxides have the advantages of being cheaper, low agglomeration, high melting point and more environmentally benign (Cabello et al, 2014a;Adanez et al, 2012;Neal et al, 2014Neal et al, , 2015Shafiefarhood et al, 2014;Galinsky et al, 2015). However, iron oxide based redox catalysts are not particularly active for methane oxidation (Cabello et al, 2014a;Shafiefarhood et al, 2014), and tend to have low selectivity toward methane partial oxidation. Notably, the reactivity and selectivity in CLMR process can be improved by combining different materials to bring synergetic effect or form solid solution (spinel, perovskite, et al) (Cabello et al, 2014a;Neal et al, 2014Neal et al, , 2015Bhavsar and Veser, 2013;Zhu et al, 2014;Chen et al, 2014).…”

Ca1−A MnO3 (A = Sr and Ba) perovskite based oxygen carriers for chemical looping with oxygen uncoupling (CLOU)

“…Typical perovskite takes the form of ABO 3Àd , where A is a large cation of either the alkali earth or rare earth metal and B is a smaller transition metal cation [55]. As a support, mixed ionic and electronic conductive (MIEC) perovskites such as La 1Àx Sr x FeO 3 (LSF) have shown to enhance the redox activity of iron oxides by nearly two orders of magnitude [51][52][53][54]. Perovskite and perovskite supported iron oxide have also been explored as redox catalysts for syngas generation and water-splitting [42,56].…”