Effect of Mn-doped CaO on NO reduction by CO in carbonation stage of calcium looping: A density functional theory study. Issue 1 (February 2022)

• Record Type: Journal Article
• Authors: Chai, Shoubing; Li, Yingjie; Zhang, Wan; Wang, Yuzhuo; Yang, Liguo; Fan, Xiaoxu; Chu, Leizhe
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 1(2022)
• Publication Date: 2022-02
• Subjects: Calcium looping -- Mn-doped CaO -- NO reduction by CO -- Carbonation stage -- Density functional theory; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.106987
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Calcium looping uses CaO carbonation/calcination cycles to capture CO2, which is a promising carbon capture technology for coal-fired power plants. However, after CaO absorbs CO2 to generate CaCO3, the catalytic performance of CaO for NOx reduction by CO decreases drastically. In this work, Mn-doped CaO was used to improve NO reduction by CO in carbonation of calcium looping and the mechanism of Mn-doped CaO on NO reduction by CO was determined by the density functional theory. The experimental results show that Mn doping not only improves the CO2 capture capacity of CaO, but also increases NO reduction by CO. Density functional theory calculation results show that the Mn atom provides new adsorption sites for CO and NO on CaO surface, respectively. After addition of Mn, the values of co-adsorption energy for CO and NO on CaO surface increases by 1.5 and 6.9 times in the carbonation stage, respectively. In addition, the total energy barrier for the reaction of NO reduction by CO under the catalysis of CaO in carbonation stage decreases from 11.08 to 8.66 eV due to the addition of Mn. The negative effect of the carbonation of CaO on NO removal by CO is greatly mitigated by Mn. Therefore, NO removal by CO in the presence of Mn-doped CaO is significantly improved in the carbonation stage of the calcium looping. Graphical Abstract: ga1 Highlights: Effect of Mn-doped CaO on NO-CO reaction in calcium looping was studied by DFT. Mn significantly catalyzes NO removal by CO in carbonation stage of calcium looping. Mn changes reaction paths and the adsorption sites of NO and CO in presence of CaO. Mn decreases energy barriers of NO reduction reaction by CO from 11.08 to 8.66 eV.