Correlating electronegativity in bimetallic oxygen carriers for chemical looping combustion

Metallic tailoring of oxygen carrier plays a crucial role within chemical looping combustion (CLC) applications, which can be correlated to the redox reaction enhancement and sustainability. Such attributes arise from the electric valence of the material constituents, which can bring about superior oxygen vacancy and structural stability. In the concurrent study, the role of electronegativity of the bimetallic carriers upon CLC performance was scrutinized based on various bimetallic metal oxides composition. Two metallic systems were examined in the current study: Iron based oxides and copper-based oxides, where the secondary metallic element within each of the examined oxide carrier is composed of one of the 5 metallic elements, predefined for the purpose of electronegativity variation. The secondary metallic element include: Calcium, Lanthanum, Magnesium, Manganese, and Chromium. Several gas byproducts were monitored during the course of the CLC reaction, via mass spectrometer, in order to quantify the variations incurred as a result of different metallic composition inclusion. Additionally, electron microscopic techniques, such as the SEM, were utilized in the study, so as to visualize the structural alteration of sintered materials. The experimental results indicate a higher reactivity with the fuel at a higher electronegativity difference within the bimetallic structure, in the case of iron-based oxide system. Also, copper-based oxide system was associated with higher carbon dioxide production with higher selectivity, relative to iron-based oxide systems.

Automated summary

Metallic tailoring plays a crucial role in chemical looping combustion (CLC) applications. The role of electronegativity of bimetallic carriers upon CLC performance was investigated in this study. Results revealed that a higher electronegativity difference within the bimetallic structure leads to higher reactivity in the iron-based oxide system.