Theoretical Study of NO Adsorption by Hydroxyl-Containing Char with the Participation of Na/K

Long Chen; Jiancheng Yang; Mingkai Zhang; Mengkai Gao; Jiachun Su; Yuan Huang; Zhikun Zhang; Zhuozhi Wang; Lianfei Xu; Boxiong Shen

doi:10.1021/acs.langmuir.2c01244

Theoretical Study of NO Adsorption by Hydroxyl-Containing Char with the Participation of Na/K

Langmuir. 2022 Aug 16;38(32):9940-9954. doi: 10.1021/acs.langmuir.2c01244. Epub 2022 Aug 2.

Authors

Long Chen¹, Jiancheng Yang^{1

2}, Mingkai Zhang¹, Mengkai Gao¹, Jiachun Su¹, Yuan Huang¹, Zhikun Zhang^{1

2}, Zhuozhi Wang³, Lianfei Xu¹, Boxiong Shen^{1

2

3}

Affiliations

¹ Tianjin Key Laboratory of Clean Energy and Pollutant Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China.
² Hebei Engineering Research Center of Pollution Control in Power System, Tianjin 300401, China.
³ National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization, School of Chemical Engineering, Hebei University of Technology, Tianjin 300401, China.

PMID: 35917436
DOI: 10.1021/acs.langmuir.2c01244

Abstract

The study of the effects of Na and K on the heterogeneous adsorption of hydroxyl-containing char with NO is important for the clean utilization of high alkali coal. In this paper, the effects of Na/K atoms on the adsorption of NO on the char surface were investigated at the GGA-PBE level by choosing zigzag type, armchair type, and saturated hydroxyl-containing char structures based on DFT. It was found that the adsorption stability of NO on structures with active sites was greater for sites close to the hydroxyl group than that for sites far from the hydroxyl group. The stability of char doped by Na/K is related to the char structure and the position of functional groups. The most stable Na/K doped structures are Z-OH-2 (E_ads= -350.50 kJ/mol) and A-OH-1-2 (E_ads= -339.17 kJ/mol), respectively. The participation of Na/K can increase the adsorption energy of the three structures with NO, and especially the adsorption energy of saturated char with NO is increased by as much as 5 times. The reason for that is the promotion of the hybridization of the C and NO p orbitals. The comprehensive analysis of electrostatic potential, charge transfer, and front orbitals indicates that the effects of decorated sodium and potassium atoms on the char surface are very similar. This study lays a theoretical foundation for the study of the heterogeneous reduction process.