Experimental and DFT research for the effects of sodium on the heterogeneous reaction between NO and semichar derived fromO₂/CO₂ pretreatments

¹ School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
² School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, China

^a arctanty@163.com
^b* sunsr@hit.edu.cn
^c 2021115@hebut.edu.cn
^d 283507571@qq.com

Abstract

The excessive emission of NO is endangering the ecological environment and the health of humans. In-depth research on the reduction mechanisms of NO is crucial to regulating NO emissions. In this research, the influence of sodium on the heterogeneous reaction of NO by semichar derived from O₂/CO₂ pretreatments were investigated through the experimental and density functional theory (DFT) method. According to the results of atomic dipole corrected Hirshfeld atomic charge (ADCH), the additional Na and oxygen-containing compound altered the semichar's charge distribution of. The additional Na weakened the positive effects of the marginal hydrogen. And the charge of the carbon, which was attached to the phenol group, changed from negative to positive due to the strong electron-trapping ability of the phenol group. The energy potential diagrams between NO and semichars derived from O₂/CO₂ pretreatments without/with sodium addition reflected that sodium was beneficial to reduce NO. Compared with pure O₂/CO₂ pretreatments, the additional sodium decreased the energy gap of the NO reduction by 144.68 kJ/mol. On the other hand, the temperature-programmed reduction (TPR) results were performed to identify the accuracy of the calculation results. The experimental results illustrated that adding sodium enhanced the NO reducibility of semichar, expressing great consistency with the theoretical results.