文献类型：期刊文献

英文题名：LaNixFe1_xO3 as flexible oxygen or carbon carriers for tunable syngas production and CO2 utilization

作者：Iftikhar, Sherafghan[1];Martin, William[1];Gao, Yunfei[1,2];Yu, Xinbin[3,4];Wang, Iwei[1];Wu, Zili[3,4];Li, Fanxing[1]

机构：[1]North Carolina State Univ, Dept Chem & Biomol Engn, Raleigh, NC 27695 USA;[2]East China Univ Sci & Technol, Shanghai Engn Res Ctr Coal Gasificat, Key Lab Coal Gasificat & Energy Chem Engn, Minist Educ, Shanghai 200237, Peoples R China;[3]Oak Ridge Natl Lab, Chem Sci Div, Oak Ridge, TN USA;[4]Ctr Nanophase Mat Sci, Oak Ridge, TN USA

年份：2023

卷号：416

外文期刊名：CATALYSIS TODAY

收录：;EI(收录号：20223312577593);WOS:【SCI-EXPANDED(收录号:WOS:000999887500001)】；

基金：This work was supported by the U.S. Department of Energy (Award DE-FE0031703) , the National Science Foundation (CBET-1923468) , and the North Carolina State University Kenan Institute for Engineering,Technology and Science (USA) . The authors acknowledge the use of the Analytical Instrumentation Facility (AIF) at North Carolina State University, which is supported by the State of North Carolina and the National Science Foundation. The Raman study was conducted as part of a user project at the Center for Nanophase Materials Sciences (CNMS) , which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory.

语种：英文

外文关键词：CO2 utilization; Syngas; Methane; Chemical looping; Redox catalyst; Hydrogen

摘要：The current study reports LaFe1_ xNixO3_delta redox catalysts as flexible oxygen or carbon carriers for CO2 utilization and tunable production of syngas at relatively low temperatures (-700 degrees C), in the context of a hybrid redox process. Specifically, perovskite-structured LaFe1_xNixO3_delta with seven different compositions (x = 0.4-1) were prepared and investigated. Cyclic experiments under alternating methane and CO2 flows indicated that all the samples exhibited favorable reactive performance: CH4 and CO2 conversions varied between 85% and 98% and 70-88%, respectively. While H2/CO ratio from Fe-rich redox catalysts was-2.3:1 in the methane conversion step, Ni-rich catalysts produced a concentrated (-93.7 vol%) hydrogen stream via methane cracking. The flexibility of LaFe1_xNixO3_delta to produce syngas (or hydrogen) with tunable compositions was found to be governed by the iron/nickel (Fe/Ni) ratio. Redox catalysts with higher Fe contents act as a lattice oxygen carrier via chemical looping partial oxidation (CLPOx) of methane whereas those with higher Ni contents function as a carbon carrier via chemical looping methane cracking (CLMC) scheme. XRD analysis and temperature -programmed reactions revealed that both types of catalysts involve the formation of La2O3 and Ni0 /Ni-Fe phases under the methane environment. The ability to re-incorporate La2O3 and Ni/Fe into a perovskite structure gives rise to oxygen-carrying capacity whereas stable Ni0 or Ni/Fe phases would catalyze methane cracking without lattice oxygen exchange in the reaction cycles. Temperature programmed oxidation and Raman spec-troscopy indicated the presence of graphitic and amorphous carbon species, which were effectively gasified by CO2 to produce concentrated CO. Stability tests over LaFe0.5Ni0.5O3 and LaNiO3 revealed that the redox per-formance was stable over a span of 50 cycles.